diff options
Diffstat (limited to 'doc/html')
54 files changed, 17939 insertions, 0 deletions
diff --git a/doc/html/NON-AUTOTOOLS-BUILD.txt b/doc/html/NON-AUTOTOOLS-BUILD.txt new file mode 100644 index 0000000..cddf3e0 --- /dev/null +++ b/doc/html/NON-AUTOTOOLS-BUILD.txt @@ -0,0 +1,764 @@ +Building PCRE without using autotools +------------------------------------- + +This document contains the following sections: + + General + Generic instructions for the PCRE C library + The C++ wrapper functions + Building for virtual Pascal + Stack size in Windows environments + Linking programs in Windows environments + Calling conventions in Windows environments + Comments about Win32 builds + Building PCRE on Windows with CMake + Use of relative paths with CMake on Windows + Testing with RunTest.bat + Building under Windows CE with Visual Studio 200x + Building under Windows with BCC5.5 + Building using Borland C++ Builder 2007 (CB2007) and higher + Building PCRE on OpenVMS + Building PCRE on Stratus OpenVOS + Building PCRE on native z/OS and z/VM + + +GENERAL + +I (Philip Hazel) have no experience of Windows or VMS sytems and how their +libraries work. The items in the PCRE distribution and Makefile that relate to +anything other than Linux systems are untested by me. + +There are some other comments and files (including some documentation in CHM +format) in the Contrib directory on the FTP site: + + ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib + +The basic PCRE library consists entirely of code written in Standard C, and so +should compile successfully on any system that has a Standard C compiler and +library. The C++ wrapper functions are a separate issue (see below). + +The PCRE distribution includes a "configure" file for use by the configure/make +(autotools) build system, as found in many Unix-like environments. The README +file contains information about the options for "configure". + +There is also support for CMake, which some users prefer, especially in Windows +environments, though it can also be run in Unix-like environments. See the +section entitled "Building PCRE on Windows with CMake" below. + +Versions of config.h and pcre.h are distributed in the PCRE tarballs under the +names config.h.generic and pcre.h.generic. These are provided for those who +build PCRE without using "configure" or CMake. If you use "configure" or CMake, +the .generic versions are not used. + + +GENERIC INSTRUCTIONS FOR THE PCRE C LIBRARY + +The following are generic instructions for building the PCRE C library "by +hand". If you are going to use CMake, this section does not apply to you; you +can skip ahead to the CMake section. + + (1) Copy or rename the file config.h.generic as config.h, and edit the macro + settings that it contains to whatever is appropriate for your environment. + + In particular, you can alter the definition of the NEWLINE macro to + specify what character(s) you want to be interpreted as line terminators. + In an EBCDIC environment, you MUST change NEWLINE, because its default + value is 10, an ASCII LF. The usual EBCDIC newline character is 21 (0x15, + NL), though in some cases it may be 37 (0x25). + + When you compile any of the PCRE modules, you must specify -DHAVE_CONFIG_H + to your compiler so that config.h is included in the sources. + + An alternative approach is not to edit config.h, but to use -D on the + compiler command line to make any changes that you need to the + configuration options. In this case -DHAVE_CONFIG_H must not be set. + + NOTE: There have been occasions when the way in which certain parameters + in config.h are used has changed between releases. (In the configure/make + world, this is handled automatically.) When upgrading to a new release, + you are strongly advised to review config.h.generic before re-using what + you had previously. + + (2) Copy or rename the file pcre.h.generic as pcre.h. + + (3) EITHER: + Copy or rename file pcre_chartables.c.dist as pcre_chartables.c. + + OR: + Compile dftables.c as a stand-alone program (using -DHAVE_CONFIG_H if + you have set up config.h), and then run it with the single argument + "pcre_chartables.c". This generates a set of standard character tables + and writes them to that file. The tables are generated using the default + C locale for your system. If you want to use a locale that is specified + by LC_xxx environment variables, add the -L option to the dftables + command. You must use this method if you are building on a system that + uses EBCDIC code. + + The tables in pcre_chartables.c are defaults. The caller of PCRE can + specify alternative tables at run time. + + (4) Ensure that you have the following header files: + + pcre_internal.h + ucp.h + + (5) For an 8-bit library, compile the following source files, setting + -DHAVE_CONFIG_H as a compiler option if you have set up config.h with your + configuration, or else use other -D settings to change the configuration + as required. + + pcre_byte_order.c + pcre_chartables.c + pcre_compile.c + pcre_config.c + pcre_dfa_exec.c + pcre_exec.c + pcre_fullinfo.c + pcre_get.c + pcre_globals.c + pcre_jit_compile.c + pcre_maketables.c + pcre_newline.c + pcre_ord2utf8.c + pcre_refcount.c + pcre_string_utils.c + pcre_study.c + pcre_tables.c + pcre_ucd.c + pcre_valid_utf8.c + pcre_version.c + pcre_xclass.c + + Make sure that you include -I. in the compiler command (or equivalent for + an unusual compiler) so that all included PCRE header files are first + sought in the current directory. Otherwise you run the risk of picking up + a previously-installed file from somewhere else. + + Note that you must still compile pcre_jit_compile.c, even if you have not + defined SUPPORT_JIT in config.h, because when JIT support is not + configured, dummy functions are compiled. When JIT support IS configured, + pcre_jit_compile.c #includes sources from the sljit subdirectory, where + there should be 16 files, all of whose names begin with "sljit". + + (6) Now link all the compiled code into an object library in whichever form + your system keeps such libraries. This is the basic PCRE C 8-bit library. + If your system has static and shared libraries, you may have to do this + once for each type. + + (7) If you want to build a 16-bit library (as well as, or instead of the 8-bit + or 32-bit libraries) repeat steps 5-6 with the following files: + + pcre16_byte_order.c + pcre16_chartables.c + pcre16_compile.c + pcre16_config.c + pcre16_dfa_exec.c + pcre16_exec.c + pcre16_fullinfo.c + pcre16_get.c + pcre16_globals.c + pcre16_jit_compile.c + pcre16_maketables.c + pcre16_newline.c + pcre16_ord2utf16.c + pcre16_refcount.c + pcre16_string_utils.c + pcre16_study.c + pcre16_tables.c + pcre16_ucd.c + pcre16_utf16_utils.c + pcre16_valid_utf16.c + pcre16_version.c + pcre16_xclass.c + + (8) If you want to build a 32-bit library (as well as, or instead of the 8-bit + or 16-bit libraries) repeat steps 5-6 with the following files: + + pcre32_byte_order.c + pcre32_chartables.c + pcre32_compile.c + pcre32_config.c + pcre32_dfa_exec.c + pcre32_exec.c + pcre32_fullinfo.c + pcre32_get.c + pcre32_globals.c + pcre32_jit_compile.c + pcre32_maketables.c + pcre32_newline.c + pcre32_ord2utf32.c + pcre32_refcount.c + pcre32_string_utils.c + pcre32_study.c + pcre32_tables.c + pcre32_ucd.c + pcre32_utf32_utils.c + pcre32_valid_utf32.c + pcre32_version.c + pcre32_xclass.c + + (9) If you want to build the POSIX wrapper functions (which apply only to the + 8-bit library), ensure that you have the pcreposix.h file and then compile + pcreposix.c (remembering -DHAVE_CONFIG_H if necessary). Link the result + (on its own) as the pcreposix library. + +(10) The pcretest program can be linked with any combination of the 8-bit, + 16-bit and 32-bit libraries (depending on what you selected in config.h). + Compile pcretest.c and pcre_printint.c (again, don't forget + -DHAVE_CONFIG_H) and link them together with the appropriate library/ies. + If you compiled an 8-bit library, pcretest also needs the pcreposix + wrapper library unless you compiled it with -DNOPOSIX. + +(11) Run pcretest on the testinput files in the testdata directory, and check + that the output matches the corresponding testoutput files. There are + comments about what each test does in the section entitled "Testing PCRE" + in the README file. If you compiled more than one of the 8-bit, 16-bit and + 32-bit libraries, you need to run pcretest with the -16 option to do + 16-bit tests and with the -32 option to do 32-bit tests. + + Some tests are relevant only when certain build-time options are selected. + For example, test 4 is for UTF-8/UTF-16/UTF-32 support, and will not run + if you have built PCRE without it. See the comments at the start of each + testinput file. If you have a suitable Unix-like shell, the RunTest script + will run the appropriate tests for you. The command "RunTest list" will + output a list of all the tests. + + Note that the supplied files are in Unix format, with just LF characters + as line terminators. You may need to edit them to change this if your + system uses a different convention. If you are using Windows, you probably + should use the wintestinput3 file instead of testinput3 (and the + corresponding output file). This is a locale test; wintestinput3 sets the + locale to "french" rather than "fr_FR", and there some minor output + differences. + +(12) If you have built PCRE with SUPPORT_JIT, the JIT features will be tested + by the testdata files. However, you might also like to build and run + the freestanding JIT test program, pcre_jit_test.c. + +(13) If you want to use the pcregrep command, compile and link pcregrep.c; it + uses only the basic 8-bit PCRE library (it does not need the pcreposix + library). + + +THE C++ WRAPPER FUNCTIONS + +The PCRE distribution also contains some C++ wrapper functions and tests, +applicable to the 8-bit library, which were contributed by Google Inc. On a +system that can use "configure" and "make", the functions are automatically +built into a library called pcrecpp. It should be straightforward to compile +the .cc files manually on other systems. The files called xxx_unittest.cc are +test programs for each of the corresponding xxx.cc files. + + +BUILDING FOR VIRTUAL PASCAL + +A script for building PCRE using Borland's C++ compiler for use with VPASCAL +was contributed by Alexander Tokarev. Stefan Weber updated the script and added +additional files. The following files in the distribution are for building PCRE +for use with VP/Borland: makevp_c.txt, makevp_l.txt, makevp.bat, pcregexp.pas. + + +STACK SIZE IN WINDOWS ENVIRONMENTS + +The default processor stack size of 1Mb in some Windows environments is too +small for matching patterns that need much recursion. In particular, test 2 may +fail because of this. Normally, running out of stack causes a crash, but there +have been cases where the test program has just died silently. See your linker +documentation for how to increase stack size if you experience problems. The +Linux default of 8Mb is a reasonable choice for the stack, though even that can +be too small for some pattern/subject combinations. + +PCRE has a compile configuration option to disable the use of stack for +recursion so that heap is used instead. However, pattern matching is +significantly slower when this is done. There is more about stack usage in the +"pcrestack" documentation. + + +LINKING PROGRAMS IN WINDOWS ENVIRONMENTS + +If you want to statically link a program against a PCRE library in the form of +a non-dll .a file, you must define PCRE_STATIC before including pcre.h or +pcrecpp.h, otherwise the pcre_malloc() and pcre_free() exported functions will +be declared __declspec(dllimport), with unwanted results. + + +CALLING CONVENTIONS IN WINDOWS ENVIRONMENTS + +It is possible to compile programs to use different calling conventions using +MSVC. Search the web for "calling conventions" for more information. To make it +easier to change the calling convention for the exported functions in the +PCRE library, the macro PCRE_CALL_CONVENTION is present in all the external +definitions. It can be set externally when compiling (e.g. in CFLAGS). If it is +not set, it defaults to empty; the default calling convention is then used +(which is what is wanted most of the time). + + +COMMENTS ABOUT WIN32 BUILDS (see also "BUILDING PCRE ON WINDOWS WITH CMAKE") + +There are two ways of building PCRE using the "configure, make, make install" +paradigm on Windows systems: using MinGW or using Cygwin. These are not at all +the same thing; they are completely different from each other. There is also +support for building using CMake, which some users find a more straightforward +way of building PCRE under Windows. + +The MinGW home page (http://www.mingw.org/) says this: + + MinGW: A collection of freely available and freely distributable Windows + specific header files and import libraries combined with GNU toolsets that + allow one to produce native Windows programs that do not rely on any + 3rd-party C runtime DLLs. + +The Cygwin home page (http://www.cygwin.com/) says this: + + Cygwin is a Linux-like environment for Windows. It consists of two parts: + + . A DLL (cygwin1.dll) which acts as a Linux API emulation layer providing + substantial Linux API functionality + + . A collection of tools which provide Linux look and feel. + + The Cygwin DLL currently works with all recent, commercially released x86 32 + bit and 64 bit versions of Windows, with the exception of Windows CE. + +On both MinGW and Cygwin, PCRE should build correctly using: + + ./configure && make && make install + +This should create two libraries called libpcre and libpcreposix, and, if you +have enabled building the C++ wrapper, a third one called libpcrecpp. These are +independent libraries: when you link with libpcreposix or libpcrecpp you must +also link with libpcre, which contains the basic functions. (Some earlier +releases of PCRE included the basic libpcre functions in libpcreposix. This no +longer happens.) + +A user submitted a special-purpose patch that makes it easy to create +"pcre.dll" under mingw32 using the "msys" environment. It provides "pcre.dll" +as a special target. If you use this target, no other files are built, and in +particular, the pcretest and pcregrep programs are not built. An example of how +this might be used is: + + ./configure --enable-utf --disable-cpp CFLAGS="-03 -s"; make pcre.dll + +Using Cygwin's compiler generates libraries and executables that depend on +cygwin1.dll. If a library that is generated this way is distributed, +cygwin1.dll has to be distributed as well. Since cygwin1.dll is under the GPL +licence, this forces not only PCRE to be under the GPL, but also the entire +application. A distributor who wants to keep their own code proprietary must +purchase an appropriate Cygwin licence. + +MinGW has no such restrictions. The MinGW compiler generates a library or +executable that can run standalone on Windows without any third party dll or +licensing issues. + +But there is more complication: + +If a Cygwin user uses the -mno-cygwin Cygwin gcc flag, what that really does is +to tell Cygwin's gcc to use the MinGW gcc. Cygwin's gcc is only acting as a +front end to MinGW's gcc (if you install Cygwin's gcc, you get both Cygwin's +gcc and MinGW's gcc). So, a user can: + +. Build native binaries by using MinGW or by getting Cygwin and using + -mno-cygwin. + +. Build binaries that depend on cygwin1.dll by using Cygwin with the normal + compiler flags. + +The test files that are supplied with PCRE are in UNIX format, with LF +characters as line terminators. Unless your PCRE library uses a default newline +option that includes LF as a valid newline, it may be necessary to change the +line terminators in the test files to get some of the tests to work. + + +BUILDING PCRE ON WINDOWS WITH CMAKE + +CMake is an alternative configuration facility that can be used instead of +"configure". CMake creates project files (make files, solution files, etc.) +tailored to numerous development environments, including Visual Studio, +Borland, Msys, MinGW, NMake, and Unix. If possible, use short paths with no +spaces in the names for your CMake installation and your PCRE source and build +directories. + +The following instructions were contributed by a PCRE user. If they are not +followed exactly, errors may occur. In the event that errors do occur, it is +recommended that you delete the CMake cache before attempting to repeat the +CMake build process. In the CMake GUI, the cache can be deleted by selecting +"File > Delete Cache". + +1. Install the latest CMake version available from http://www.cmake.org/, and + ensure that cmake\bin is on your path. + +2. Unzip (retaining folder structure) the PCRE source tree into a source + directory such as C:\pcre. You should ensure your local date and time + is not earlier than the file dates in your source dir if the release is + very new. + +3. Create a new, empty build directory, preferably a subdirectory of the + source dir. For example, C:\pcre\pcre-xx\build. + +4. Run cmake-gui from the Shell envirornment of your build tool, for example, + Msys for Msys/MinGW or Visual Studio Command Prompt for VC/VC++. Do not try + to start Cmake from the Windows Start menu, as this can lead to errors. + +5. Enter C:\pcre\pcre-xx and C:\pcre\pcre-xx\build for the source and build + directories, respectively. + +6. Hit the "Configure" button. + +7. Select the particular IDE / build tool that you are using (Visual + Studio, MSYS makefiles, MinGW makefiles, etc.) + +8. The GUI will then list several configuration options. This is where + you can enable UTF-8 support or other PCRE optional features. + +9. Hit "Configure" again. The adjacent "Generate" button should now be + active. + +10. Hit "Generate". + +11. The build directory should now contain a usable build system, be it a + solution file for Visual Studio, makefiles for MinGW, etc. Exit from + cmake-gui and use the generated build system with your compiler or IDE. + E.g., for MinGW you can run "make", or for Visual Studio, open the PCRE + solution, select the desired configuration (Debug, or Release, etc.) and + build the ALL_BUILD project. + +12. If during configuration with cmake-gui you've elected to build the test + programs, you can execute them by building the test project. E.g., for + MinGW: "make test"; for Visual Studio build the RUN_TESTS project. The + most recent build configuration is targeted by the tests. A summary of + test results is presented. Complete test output is subsequently + available for review in Testing\Temporary under your build dir. + + +USE OF RELATIVE PATHS WITH CMAKE ON WINDOWS + +A PCRE user comments as follows: I thought that others may want to know the +current state of CMAKE_USE_RELATIVE_PATHS support on Windows. Here it is: + +-- AdditionalIncludeDirectories is only partially modified (only the + first path - see below) +-- Only some of the contained file paths are modified - shown below for + pcre.vcproj +-- It properly modifies + +I am sure CMake people can fix that if they want to. Until then one will +need to replace existing absolute paths in project files with relative +paths manually (e.g. from VS) - relative to project file location. I did +just that before being told to try CMAKE_USE_RELATIVE_PATHS. Not a big +deal. + +AdditionalIncludeDirectories="E:\builds\pcre\build;E:\builds\pcre\pcre-7.5;" +AdditionalIncludeDirectories=".;E:\builds\pcre\pcre-7.5;" + +RelativePath="pcre.h" +RelativePath="pcre_chartables.c" +RelativePath="pcre_chartables.c.rule" + + +TESTING WITH RUNTEST.BAT + +If configured with CMake, building the test project ("make test" or building +ALL_TESTS in Visual Studio) creates (and runs) pcre_test.bat (and depending +on your configuration options, possibly other test programs) in the build +directory. Pcre_test.bat runs RunTest.Bat with correct source and exe paths. + +For manual testing with RunTest.bat, provided the build dir is a subdirectory +of the source directory: Open command shell window. Chdir to the location +of your pcretest.exe and pcregrep.exe programs. Call RunTest.bat with +"..\RunTest.Bat" or "..\..\RunTest.bat" as appropriate. + +To run only a particular test with RunTest.Bat provide a test number argument. + +Otherwise: + +1. Copy RunTest.bat into the directory where pcretest.exe and pcregrep.exe + have been created. + +2. Edit RunTest.bat to indentify the full or relative location of + the pcre source (wherein which the testdata folder resides), e.g.: + + set srcdir=C:\pcre\pcre-8.20 + +3. In a Windows command environment, chdir to the location of your bat and + exe programs. + +4. Run RunTest.bat. Test outputs will automatically be compared to expected + results, and discrepancies will be identified in the console output. + +To independently test the just-in-time compiler, run pcre_jit_test.exe. +To test pcrecpp, run pcrecpp_unittest.exe, pcre_stringpiece_unittest.exe and +pcre_scanner_unittest.exe. + + +BUILDING UNDER WINDOWS CE WITH VISUAL STUDIO 200x + +Vincent Richomme sent a zip archive of files to help with this process. They +can be found in the file "pcre-vsbuild.zip" in the Contrib directory of the FTP +site. + + +BUILDING UNDER WINDOWS WITH BCC5.5 + +Michael Roy sent these comments about building PCRE under Windows with BCC5.5: + +Some of the core BCC libraries have a version of PCRE from 1998 built in, which +can lead to pcre_exec() giving an erroneous PCRE_ERROR_NULL from a version +mismatch. I'm including an easy workaround below, if you'd like to include it +in the non-unix instructions: + +When linking a project with BCC5.5, pcre.lib must be included before any of the +libraries cw32.lib, cw32i.lib, cw32mt.lib, and cw32mti.lib on the command line. + + +BUILDING USING BORLAND C++ BUILDER 2007 (CB2007) AND HIGHER + +A PCRE user sent these comments about this environment (see also the comment +from another user that follows them): + +The XE versions of C++ Builder come with a RegularExpressionsCore class which +contain a version of TPerlRegEx. However, direct use of the C PCRE library may +be desirable. + +The default makevp.bat, however, supplied with PCRE builds a version of PCRE +that is not usable with any version of C++ Builder because the compiler ships +with an embedded version of PCRE, version 2.01 from 1998! [See also the note +about BCC5.5 above.] If you want to use PCRE you'll need to rename the +functions (pcre_compile to pcre_compile_bcc, etc) or do as I have done and just +use the 16 bit versions. I'm using std::wstring everywhere anyway. Since the +embedded version of PCRE does not have the 16 bit function names, there is no +conflict. + +Building PCRE using a C++ Builder static library project file (recommended): + +1. Rename or remove pcre.h, pcreposi.h, and pcreposix.h from your C++ Builder +original include path. + +2. Download PCRE from pcre.org and extract to a directory. + +3. Rename pcre_chartables.c.dist to pcre_chartables.c, pcre.h.generic to +pcre.h, and config.h.generic to config.h. + +4. Edit pcre.h and pcre_config.c so that they include config.h. + +5. Edit config.h like so: + +Comment out the following lines: +#define PACKAGE "pcre" +#define PACKAGE_BUGREPORT "" +#define PACKAGE_NAME "PCRE" +#define PACKAGE_STRING "PCRE 8.32" +#define PACKAGE_TARNAME "pcre" +#define PACKAGE_URL "" +#define PACKAGE_VERSION "8.32" + +Add the following lines: +#ifndef SUPPORT_UTF +#define SUPPORT_UTF 100 // any value is fine +#endif + +#ifndef SUPPORT_UCP +#define SUPPORT_UCP 101 // any value is fine +#endif + +#ifndef SUPPORT_UCP +#define SUPPORT_PCRE16 102 // any value is fine +#endif + +#ifndef SUPPORT_UTF8 +#define SUPPORT_UTF8 103 // any value is fine +#endif + +6. Build a C++ Builder project using the IDE. Go to File / New / Other and +choose Static Library. You can name it pcre.cbproj or whatever. Now set your +paths by going to Project / Options. Set the Include path. Do this from the +"Base" option to apply to both Release and Debug builds. Now add the following +files to the project: + +pcre.h +pcre16_byte_order.c +pcre16_chartables.c +pcre16_compile.c +pcre16_config.c +pcre16_dfa_exec.c +pcre16_exec.c +pcre16_fullinfo.c +pcre16_get.c +pcre16_globals.c +pcre16_maketables.c +pcre16_newline.c +pcre16_ord2utf16.c +pcre16_printint.c +pcre16_refcount.c +pcre16_string_utils.c +pcre16_study.c +pcre16_tables.c +pcre16_ucd.c +pcre16_utf16_utils.c +pcre16_valid_utf16.c +pcre16_version.c +pcre16_xclass.c + +//Optional +pcre_version.c + +7. After compiling the .lib file, copy the .lib and header files to a project +you want to use PCRE with. Enjoy. + +Optional ... Building PCRE using the makevp.bat file: + +1. Edit makevp_c.txt and makevp_l.txt and change all the names to the 16 bit +versions. + +2. Edit makevp.bat and set the path to C++ Builder. Run makevp.bat. + +Another PCRE user added this comment: + +Another approach I successfully used for some years with BCB 5 and 6 was to +make sure that include and library paths of PCRE are configured before the +default paths of the IDE in the dialogs where one can manage those paths. +Afterwards one can open the project files using a text editor and manually add +the self created library for pcre itself, pcrecpp doesn't ship with the IDE, in +the library nodes where the IDE manages its own libraries to link against in +front of the IDE-own libraries. This way one can use the default PCRE function +names without getting access violations on runtime. + + <ALLLIB value="libpcre.lib $(LIBFILES) $(LIBRARIES) import32.lib cp32mt.lib"/> + + +BUILDING PCRE ON OPENVMS + +Stephen Hoffman sent the following, in December 2012: + +"Here <http://labs.hoffmanlabs.com/node/1847> is a very short write-up on the +OpenVMS port and here + +<http://labs.hoffmanlabs.com/labsnotes/pcre-vms-8_32.zip> + +is a zip with the OpenVMS files, and with one modified testing-related PCRE +file." This is a port of PCRE 8.32. + +Earlier, Dan Mooney sent the following comments about building PCRE on OpenVMS. +They relate to an older version of PCRE that used fewer source files, so the +exact commands will need changing. See the current list of source files above. + +"It was quite easy to compile and link the library. I don't have a formal +make file but the attached file [reproduced below] contains the OpenVMS DCL +commands I used to build the library. I had to add #define +POSIX_MALLOC_THRESHOLD 10 to pcre.h since it was not defined anywhere. + +The library was built on: +O/S: HP OpenVMS v7.3-1 +Compiler: Compaq C v6.5-001-48BCD +Linker: vA13-01 + +The test results did not match 100% due to the issues you mention in your +documentation regarding isprint(), iscntrl(), isgraph() and ispunct(). I +modified some of the character tables temporarily and was able to get the +results to match. Tests using the fr locale did not match since I don't have +that locale loaded. The study size was always reported to be 3 less than the +value in the standard test output files." + +========================= +$! This DCL procedure builds PCRE on OpenVMS +$! +$! I followed the instructions in the non-unix-use file in the distribution. +$! +$ COMPILE == "CC/LIST/NOMEMBER_ALIGNMENT/PREFIX_LIBRARY_ENTRIES=ALL_ENTRIES +$ COMPILE DFTABLES.C +$ LINK/EXE=DFTABLES.EXE DFTABLES.OBJ +$ RUN DFTABLES.EXE/OUTPUT=CHARTABLES.C +$ COMPILE MAKETABLES.C +$ COMPILE GET.C +$ COMPILE STUDY.C +$! I had to set POSIX_MALLOC_THRESHOLD to 10 in PCRE.H since the symbol +$! did not seem to be defined anywhere. +$! I edited pcre.h and added #DEFINE SUPPORT_UTF8 to enable UTF8 support. +$ COMPILE PCRE.C +$ LIB/CREATE PCRE MAKETABLES.OBJ, GET.OBJ, STUDY.OBJ, PCRE.OBJ +$! I had to set POSIX_MALLOC_THRESHOLD to 10 in PCRE.H since the symbol +$! did not seem to be defined anywhere. +$ COMPILE PCREPOSIX.C +$ LIB/CREATE PCREPOSIX PCREPOSIX.OBJ +$ COMPILE PCRETEST.C +$ LINK/EXE=PCRETEST.EXE PCRETEST.OBJ, PCRE/LIB, PCREPOSIX/LIB +$! C programs that want access to command line arguments must be +$! defined as a symbol +$ PCRETEST :== "$ SYS$ROADSUSERS:[DMOONEY.REGEXP]PCRETEST.EXE" +$! Arguments must be enclosed in quotes. +$ PCRETEST "-C" +$! Test results: +$! +$! The test results did not match 100%. The functions isprint(), iscntrl(), +$! isgraph() and ispunct() on OpenVMS must not produce the same results +$! as the system that built the test output files provided with the +$! distribution. +$! +$! The study size did not match and was always 3 less on OpenVMS. +$! +$! Locale could not be set to fr +$! +========================= + + +BUILDING PCRE ON STRATUS OPENVOS + +These notes on the port of PCRE to VOS (lightly edited) were supplied by +Ashutosh Warikoo, whose email address has the local part awarikoo and the +domain nse.co.in. The port was for version 7.9 in August 2009. + +1. Building PCRE + +I built pcre on OpenVOS Release 17.0.1at using GNU Tools 3.4a without any +problems. I used the following packages to build PCRE: + + ftp://ftp.stratus.com/pub/vos/posix/ga/posix.save.evf.gz + +Please read and follow the instructions that come with these packages. To start +the build of pcre, from the root of the package type: + + ./build.sh + +2. Installing PCRE + +Once you have successfully built PCRE, login to the SysAdmin group, switch to +the root user, and type + + [ !create_dir (master_disk)>usr --if needed ] + [ !create_dir (master_disk)>usr>local --if needed ] + !gmake install + +This installs PCRE and its man pages into /usr/local. You can add +(master_disk)>usr>local>bin to your command search paths, or if you are in +BASH, add /usr/local/bin to the PATH environment variable. + +4. Restrictions + +This port requires readline library optionally. However during the build I +faced some yet unexplored errors while linking with readline. As it was an +optional component I chose to disable it. + +5. Known Problems + +I ran the test suite, but you will have to be your own judge of whether this +command, and this port, suits your purposes. If you find any problems that +appear to be related to the port itself, please let me know. Please see the +build.log file in the root of the package also. + + +BUILDING PCRE ON NATIVE Z/OS AND Z/VM + +z/OS and z/VM are operating systems for mainframe computers, produced by IBM. +The character code used is EBCDIC, not ASCII or Unicode. In z/OS, UNIX APIs and +applications can be supported through UNIX System Services, and in such an +environment PCRE can be built in the same way as in other systems. However, in +native z/OS (without UNIX System Services) and in z/VM, special ports are +required. For details, please see this web site: + + http://www.zaconsultants.net + +There is also a mirror here: + + http://www.vsoft-software.com/downloads.html + +========================== +Last Updated: 14 May 2013 diff --git a/doc/html/README.txt b/doc/html/README.txt new file mode 100644 index 0000000..88f2dfd --- /dev/null +++ b/doc/html/README.txt @@ -0,0 +1,991 @@ +README file for PCRE (Perl-compatible regular expression library) +----------------------------------------------------------------- + +The latest release of PCRE is always available in three alternative formats +from: + + ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.gz + ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.tar.bz2 + ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-xxx.zip + +There is a mailing list for discussion about the development of PCRE at +pcre-dev@exim.org. You can access the archives and subscribe or manage your +subscription here: + + https://lists.exim.org/mailman/listinfo/pcre-dev + +Please read the NEWS file if you are upgrading from a previous release. +The contents of this README file are: + + The PCRE APIs + Documentation for PCRE + Contributions by users of PCRE + Building PCRE on non-Unix-like systems + Building PCRE without using autotools + Building PCRE using autotools + Retrieving configuration information + Shared libraries + Cross-compiling using autotools + Using HP's ANSI C++ compiler (aCC) + Compiling in Tru64 using native compilers + Using Sun's compilers for Solaris + Using PCRE from MySQL + Making new tarballs + Testing PCRE + Character tables + File manifest + + +The PCRE APIs +------------- + +PCRE is written in C, and it has its own API. There are three sets of +functions, one for the 8-bit library, which processes strings of bytes, one for +the 16-bit library, which processes strings of 16-bit values, and one for the +32-bit library, which processes strings of 32-bit values. The distribution also +includes a set of C++ wrapper functions (see the pcrecpp man page for details), +courtesy of Google Inc., which can be used to call the 8-bit PCRE library from +C++. + +In addition, there is a set of C wrapper functions (again, just for the 8-bit +library) that are based on the POSIX regular expression API (see the pcreposix +man page). These end up in the library called libpcreposix. Note that this just +provides a POSIX calling interface to PCRE; the regular expressions themselves +still follow Perl syntax and semantics. The POSIX API is restricted, and does +not give full access to all of PCRE's facilities. + +The header file for the POSIX-style functions is called pcreposix.h. The +official POSIX name is regex.h, but I did not want to risk possible problems +with existing files of that name by distributing it that way. To use PCRE with +an existing program that uses the POSIX API, pcreposix.h will have to be +renamed or pointed at by a link. + +If you are using the POSIX interface to PCRE and there is already a POSIX regex +library installed on your system, as well as worrying about the regex.h header +file (as mentioned above), you must also take care when linking programs to +ensure that they link with PCRE's libpcreposix library. Otherwise they may pick +up the POSIX functions of the same name from the other library. + +One way of avoiding this confusion is to compile PCRE with the addition of +-Dregcomp=PCREregcomp (and similarly for the other POSIX functions) to the +compiler flags (CFLAGS if you are using "configure" -- see below). This has the +effect of renaming the functions so that the names no longer clash. Of course, +you have to do the same thing for your applications, or write them using the +new names. + + +Documentation for PCRE +---------------------- + +If you install PCRE in the normal way on a Unix-like system, you will end up +with a set of man pages whose names all start with "pcre". The one that is just +called "pcre" lists all the others. In addition to these man pages, the PCRE +documentation is supplied in two other forms: + + 1. There are files called doc/pcre.txt, doc/pcregrep.txt, and + doc/pcretest.txt in the source distribution. The first of these is a + concatenation of the text forms of all the section 3 man pages except + the listing of pcredemo.c and those that summarize individual functions. + The other two are the text forms of the section 1 man pages for the + pcregrep and pcretest commands. These text forms are provided for ease of + scanning with text editors or similar tools. They are installed in + <prefix>/share/doc/pcre, where <prefix> is the installation prefix + (defaulting to /usr/local). + + 2. A set of files containing all the documentation in HTML form, hyperlinked + in various ways, and rooted in a file called index.html, is distributed in + doc/html and installed in <prefix>/share/doc/pcre/html. + +Users of PCRE have contributed files containing the documentation for various +releases in CHM format. These can be found in the Contrib directory of the FTP +site (see next section). + + +Contributions by users of PCRE +------------------------------ + +You can find contributions from PCRE users in the directory + + ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Contrib + +There is a README file giving brief descriptions of what they are. Some are +complete in themselves; others are pointers to URLs containing relevant files. +Some of this material is likely to be well out-of-date. Several of the earlier +contributions provided support for compiling PCRE on various flavours of +Windows (I myself do not use Windows). Nowadays there is more Windows support +in the standard distribution, so these contibutions have been archived. + +A PCRE user maintains downloadable Windows binaries of the pcregrep and +pcretest programs here: + + http://www.rexegg.com/pcregrep-pcretest.html + + +Building PCRE on non-Unix-like systems +-------------------------------------- + +For a non-Unix-like system, please read the comments in the file +NON-AUTOTOOLS-BUILD, though if your system supports the use of "configure" and +"make" you may be able to build PCRE using autotools in the same way as for +many Unix-like systems. + +PCRE can also be configured using the GUI facility provided by CMake's +cmake-gui command. This creates Makefiles, solution files, etc. The file +NON-AUTOTOOLS-BUILD has information about CMake. + +PCRE has been compiled on many different operating systems. It should be +straightforward to build PCRE on any system that has a Standard C compiler and +library, because it uses only Standard C functions. + + +Building PCRE without using autotools +------------------------------------- + +The use of autotools (in particular, libtool) is problematic in some +environments, even some that are Unix or Unix-like. See the NON-AUTOTOOLS-BUILD +file for ways of building PCRE without using autotools. + + +Building PCRE using autotools +----------------------------- + +If you are using HP's ANSI C++ compiler (aCC), please see the special note +in the section entitled "Using HP's ANSI C++ compiler (aCC)" below. + +The following instructions assume the use of the widely used "configure; make; +make install" (autotools) process. + +To build PCRE on system that supports autotools, first run the "configure" +command from the PCRE distribution directory, with your current directory set +to the directory where you want the files to be created. This command is a +standard GNU "autoconf" configuration script, for which generic instructions +are supplied in the file INSTALL. + +Most commonly, people build PCRE within its own distribution directory, and in +this case, on many systems, just running "./configure" is sufficient. However, +the usual methods of changing standard defaults are available. For example: + +CFLAGS='-O2 -Wall' ./configure --prefix=/opt/local + +This command specifies that the C compiler should be run with the flags '-O2 +-Wall' instead of the default, and that "make install" should install PCRE +under /opt/local instead of the default /usr/local. + +If you want to build in a different directory, just run "configure" with that +directory as current. For example, suppose you have unpacked the PCRE source +into /source/pcre/pcre-xxx, but you want to build it in /build/pcre/pcre-xxx: + +cd /build/pcre/pcre-xxx +/source/pcre/pcre-xxx/configure + +PCRE is written in C and is normally compiled as a C library. However, it is +possible to build it as a C++ library, though the provided building apparatus +does not have any features to support this. + +There are some optional features that can be included or omitted from the PCRE +library. They are also documented in the pcrebuild man page. + +. By default, both shared and static libraries are built. You can change this + by adding one of these options to the "configure" command: + + --disable-shared + --disable-static + + (See also "Shared libraries on Unix-like systems" below.) + +. By default, only the 8-bit library is built. If you add --enable-pcre16 to + the "configure" command, the 16-bit library is also built. If you add + --enable-pcre32 to the "configure" command, the 32-bit library is also built. + If you want only the 16-bit or 32-bit library, use --disable-pcre8 to disable + building the 8-bit library. + +. If you are building the 8-bit library and want to suppress the building of + the C++ wrapper library, you can add --disable-cpp to the "configure" + command. Otherwise, when "configure" is run without --disable-pcre8, it will + try to find a C++ compiler and C++ header files, and if it succeeds, it will + try to build the C++ wrapper. + +. If you want to include support for just-in-time compiling, which can give + large performance improvements on certain platforms, add --enable-jit to the + "configure" command. This support is available only for certain hardware + architectures. If you try to enable it on an unsupported architecture, there + will be a compile time error. + +. When JIT support is enabled, pcregrep automatically makes use of it, unless + you add --disable-pcregrep-jit to the "configure" command. + +. If you want to make use of the support for UTF-8 Unicode character strings in + the 8-bit library, or UTF-16 Unicode character strings in the 16-bit library, + or UTF-32 Unicode character strings in the 32-bit library, you must add + --enable-utf to the "configure" command. Without it, the code for handling + UTF-8, UTF-16 and UTF-8 is not included in the relevant library. Even + when --enable-utf is included, the use of a UTF encoding still has to be + enabled by an option at run time. When PCRE is compiled with this option, its + input can only either be ASCII or UTF-8/16/32, even when running on EBCDIC + platforms. It is not possible to use both --enable-utf and --enable-ebcdic at + the same time. + +. There are no separate options for enabling UTF-8, UTF-16 and UTF-32 + independently because that would allow ridiculous settings such as requesting + UTF-16 support while building only the 8-bit library. However, the option + --enable-utf8 is retained for backwards compatibility with earlier releases + that did not support 16-bit or 32-bit character strings. It is synonymous with + --enable-utf. It is not possible to configure one library with UTF support + and the other without in the same configuration. + +. If, in addition to support for UTF-8/16/32 character strings, you want to + include support for the \P, \p, and \X sequences that recognize Unicode + character properties, you must add --enable-unicode-properties to the + "configure" command. This adds about 30K to the size of the library (in the + form of a property table); only the basic two-letter properties such as Lu + are supported. + +. You can build PCRE to recognize either CR or LF or the sequence CRLF or any + of the preceding, or any of the Unicode newline sequences as indicating the + end of a line. Whatever you specify at build time is the default; the caller + of PCRE can change the selection at run time. The default newline indicator + is a single LF character (the Unix standard). You can specify the default + newline indicator by adding --enable-newline-is-cr or --enable-newline-is-lf + or --enable-newline-is-crlf or --enable-newline-is-anycrlf or + --enable-newline-is-any to the "configure" command, respectively. + + If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of + the standard tests will fail, because the lines in the test files end with + LF. Even if the files are edited to change the line endings, there are likely + to be some failures. With --enable-newline-is-anycrlf or + --enable-newline-is-any, many tests should succeed, but there may be some + failures. + +. By default, the sequence \R in a pattern matches any Unicode line ending + sequence. This is independent of the option specifying what PCRE considers to + be the end of a line (see above). However, the caller of PCRE can restrict \R + to match only CR, LF, or CRLF. You can make this the default by adding + --enable-bsr-anycrlf to the "configure" command (bsr = "backslash R"). + +. When called via the POSIX interface, PCRE uses malloc() to get additional + storage for processing capturing parentheses if there are more than 10 of + them in a pattern. You can increase this threshold by setting, for example, + + --with-posix-malloc-threshold=20 + + on the "configure" command. + +. PCRE has a counter that limits the depth of nesting of parentheses in a + pattern. This limits the amount of system stack that a pattern uses when it + is compiled. The default is 250, but you can change it by setting, for + example, + + --with-parens-nest-limit=500 + +. PCRE has a counter that can be set to limit the amount of resources it uses + when matching a pattern. If the limit is exceeded during a match, the match + fails. The default is ten million. You can change the default by setting, for + example, + + --with-match-limit=500000 + + on the "configure" command. This is just the default; individual calls to + pcre_exec() can supply their own value. There is more discussion on the + pcreapi man page. + +. There is a separate counter that limits the depth of recursive function calls + during a matching process. This also has a default of ten million, which is + essentially "unlimited". You can change the default by setting, for example, + + --with-match-limit-recursion=500000 + + Recursive function calls use up the runtime stack; running out of stack can + cause programs to crash in strange ways. There is a discussion about stack + sizes in the pcrestack man page. + +. The default maximum compiled pattern size is around 64K. You can increase + this by adding --with-link-size=3 to the "configure" command. In the 8-bit + library, PCRE then uses three bytes instead of two for offsets to different + parts of the compiled pattern. In the 16-bit library, --with-link-size=3 is + the same as --with-link-size=4, which (in both libraries) uses four-byte + offsets. Increasing the internal link size reduces performance. In the 32-bit + library, the only supported link size is 4. + +. You can build PCRE so that its internal match() function that is called from + pcre_exec() does not call itself recursively. Instead, it uses memory blocks + obtained from the heap via the special functions pcre_stack_malloc() and + pcre_stack_free() to save data that would otherwise be saved on the stack. To + build PCRE like this, use + + --disable-stack-for-recursion + + on the "configure" command. PCRE runs more slowly in this mode, but it may be + necessary in environments with limited stack sizes. This applies only to the + normal execution of the pcre_exec() function; if JIT support is being + successfully used, it is not relevant. Equally, it does not apply to + pcre_dfa_exec(), which does not use deeply nested recursion. There is a + discussion about stack sizes in the pcrestack man page. + +. For speed, PCRE uses four tables for manipulating and identifying characters + whose code point values are less than 256. By default, it uses a set of + tables for ASCII encoding that is part of the distribution. If you specify + + --enable-rebuild-chartables + + a program called dftables is compiled and run in the default C locale when + you obey "make". It builds a source file called pcre_chartables.c. If you do + not specify this option, pcre_chartables.c is created as a copy of + pcre_chartables.c.dist. See "Character tables" below for further information. + +. It is possible to compile PCRE for use on systems that use EBCDIC as their + character code (as opposed to ASCII/Unicode) by specifying + + --enable-ebcdic + + This automatically implies --enable-rebuild-chartables (see above). However, + when PCRE is built this way, it always operates in EBCDIC. It cannot support + both EBCDIC and UTF-8/16/32. There is a second option, --enable-ebcdic-nl25, + which specifies that the code value for the EBCDIC NL character is 0x25 + instead of the default 0x15. + +. In environments where valgrind is installed, if you specify + + --enable-valgrind + + PCRE will use valgrind annotations to mark certain memory regions as + unaddressable. This allows it to detect invalid memory accesses, and is + mostly useful for debugging PCRE itself. + +. In environments where the gcc compiler is used and lcov version 1.6 or above + is installed, if you specify + + --enable-coverage + + the build process implements a code coverage report for the test suite. The + report is generated by running "make coverage". If ccache is installed on + your system, it must be disabled when building PCRE for coverage reporting. + You can do this by setting the environment variable CCACHE_DISABLE=1 before + running "make" to build PCRE. There is more information about coverage + reporting in the "pcrebuild" documentation. + +. The pcregrep program currently supports only 8-bit data files, and so + requires the 8-bit PCRE library. It is possible to compile pcregrep to use + libz and/or libbz2, in order to read .gz and .bz2 files (respectively), by + specifying one or both of + + --enable-pcregrep-libz + --enable-pcregrep-libbz2 + + Of course, the relevant libraries must be installed on your system. + +. The default size (in bytes) of the internal buffer used by pcregrep can be + set by, for example: + + --with-pcregrep-bufsize=51200 + + The value must be a plain integer. The default is 20480. + +. It is possible to compile pcretest so that it links with the libreadline + or libedit libraries, by specifying, respectively, + + --enable-pcretest-libreadline or --enable-pcretest-libedit + + If this is done, when pcretest's input is from a terminal, it reads it using + the readline() function. This provides line-editing and history facilities. + Note that libreadline is GPL-licenced, so if you distribute a binary of + pcretest linked in this way, there may be licensing issues. These can be + avoided by linking with libedit (which has a BSD licence) instead. + + Enabling libreadline causes the -lreadline option to be added to the pcretest + build. In many operating environments with a sytem-installed readline + library this is sufficient. However, in some environments (e.g. if an + unmodified distribution version of readline is in use), it may be necessary + to specify something like LIBS="-lncurses" as well. This is because, to quote + the readline INSTALL, "Readline uses the termcap functions, but does not link + with the termcap or curses library itself, allowing applications which link + with readline the to choose an appropriate library." If you get error + messages about missing functions tgetstr, tgetent, tputs, tgetflag, or tgoto, + this is the problem, and linking with the ncurses library should fix it. + +The "configure" script builds the following files for the basic C library: + +. Makefile the makefile that builds the library +. config.h build-time configuration options for the library +. pcre.h the public PCRE header file +. pcre-config script that shows the building settings such as CFLAGS + that were set for "configure" +. libpcre.pc ) data for the pkg-config command +. libpcre16.pc ) +. libpcre32.pc ) +. libpcreposix.pc ) +. libtool script that builds shared and/or static libraries + +Versions of config.h and pcre.h are distributed in the PCRE tarballs under the +names config.h.generic and pcre.h.generic. These are provided for those who +have to built PCRE without using "configure" or CMake. If you use "configure" +or CMake, the .generic versions are not used. + +When building the 8-bit library, if a C++ compiler is found, the following +files are also built: + +. libpcrecpp.pc data for the pkg-config command +. pcrecpparg.h header file for calling PCRE via the C++ wrapper +. pcre_stringpiece.h header for the C++ "stringpiece" functions + +The "configure" script also creates config.status, which is an executable +script that can be run to recreate the configuration, and config.log, which +contains compiler output from tests that "configure" runs. + +Once "configure" has run, you can run "make". This builds the the libraries +libpcre, libpcre16 and/or libpcre32, and a test program called pcretest. If you +enabled JIT support with --enable-jit, a test program called pcre_jit_test is +built as well. + +If the 8-bit library is built, libpcreposix and the pcregrep command are also +built, and if a C++ compiler was found on your system, and you did not disable +it with --disable-cpp, "make" builds the C++ wrapper library, which is called +libpcrecpp, as well as some test programs called pcrecpp_unittest, +pcre_scanner_unittest, and pcre_stringpiece_unittest. + +The command "make check" runs all the appropriate tests. Details of the PCRE +tests are given below in a separate section of this document. + +You can use "make install" to install PCRE into live directories on your +system. The following are installed (file names are all relative to the +<prefix> that is set when "configure" is run): + + Commands (bin): + pcretest + pcregrep (if 8-bit support is enabled) + pcre-config + + Libraries (lib): + libpcre16 (if 16-bit support is enabled) + libpcre32 (if 32-bit support is enabled) + libpcre (if 8-bit support is enabled) + libpcreposix (if 8-bit support is enabled) + libpcrecpp (if 8-bit and C++ support is enabled) + + Configuration information (lib/pkgconfig): + libpcre16.pc + libpcre32.pc + libpcre.pc + libpcreposix.pc + libpcrecpp.pc (if C++ support is enabled) + + Header files (include): + pcre.h + pcreposix.h + pcre_scanner.h ) + pcre_stringpiece.h ) if C++ support is enabled + pcrecpp.h ) + pcrecpparg.h ) + + Man pages (share/man/man{1,3}): + pcregrep.1 + pcretest.1 + pcre-config.1 + pcre.3 + pcre*.3 (lots more pages, all starting "pcre") + + HTML documentation (share/doc/pcre/html): + index.html + *.html (lots more pages, hyperlinked from index.html) + + Text file documentation (share/doc/pcre): + AUTHORS + COPYING + ChangeLog + LICENCE + NEWS + README + pcre.txt (a concatenation of the man(3) pages) + pcretest.txt the pcretest man page + pcregrep.txt the pcregrep man page + pcre-config.txt the pcre-config man page + +If you want to remove PCRE from your system, you can run "make uninstall". +This removes all the files that "make install" installed. However, it does not +remove any directories, because these are often shared with other programs. + + +Retrieving configuration information +------------------------------------ + +Running "make install" installs the command pcre-config, which can be used to +recall information about the PCRE configuration and installation. For example: + + pcre-config --version + +prints the version number, and + + pcre-config --libs + +outputs information about where the library is installed. This command can be +included in makefiles for programs that use PCRE, saving the programmer from +having to remember too many details. + +The pkg-config command is another system for saving and retrieving information +about installed libraries. Instead of separate commands for each library, a +single command is used. For example: + + pkg-config --cflags pcre + +The data is held in *.pc files that are installed in a directory called +<prefix>/lib/pkgconfig. + + +Shared libraries +---------------- + +The default distribution builds PCRE as shared libraries and static libraries, +as long as the operating system supports shared libraries. Shared library +support relies on the "libtool" script which is built as part of the +"configure" process. + +The libtool script is used to compile and link both shared and static +libraries. They are placed in a subdirectory called .libs when they are newly +built. The programs pcretest and pcregrep are built to use these uninstalled +libraries (by means of wrapper scripts in the case of shared libraries). When +you use "make install" to install shared libraries, pcregrep and pcretest are +automatically re-built to use the newly installed shared libraries before being +installed themselves. However, the versions left in the build directory still +use the uninstalled libraries. + +To build PCRE using static libraries only you must use --disable-shared when +configuring it. For example: + +./configure --prefix=/usr/gnu --disable-shared + +Then run "make" in the usual way. Similarly, you can use --disable-static to +build only shared libraries. + + +Cross-compiling using autotools +------------------------------- + +You can specify CC and CFLAGS in the normal way to the "configure" command, in +order to cross-compile PCRE for some other host. However, you should NOT +specify --enable-rebuild-chartables, because if you do, the dftables.c source +file is compiled and run on the local host, in order to generate the inbuilt +character tables (the pcre_chartables.c file). This will probably not work, +because dftables.c needs to be compiled with the local compiler, not the cross +compiler. + +When --enable-rebuild-chartables is not specified, pcre_chartables.c is created +by making a copy of pcre_chartables.c.dist, which is a default set of tables +that assumes ASCII code. Cross-compiling with the default tables should not be +a problem. + +If you need to modify the character tables when cross-compiling, you should +move pcre_chartables.c.dist out of the way, then compile dftables.c by hand and +run it on the local host to make a new version of pcre_chartables.c.dist. +Then when you cross-compile PCRE this new version of the tables will be used. + + +Using HP's ANSI C++ compiler (aCC) +---------------------------------- + +Unless C++ support is disabled by specifying the "--disable-cpp" option of the +"configure" script, you must include the "-AA" option in the CXXFLAGS +environment variable in order for the C++ components to compile correctly. + +Also, note that the aCC compiler on PA-RISC platforms may have a defect whereby +needed libraries fail to get included when specifying the "-AA" compiler +option. If you experience unresolved symbols when linking the C++ programs, +use the workaround of specifying the following environment variable prior to +running the "configure" script: + + CXXLDFLAGS="-lstd_v2 -lCsup_v2" + + +Compiling in Tru64 using native compilers +----------------------------------------- + +The following error may occur when compiling with native compilers in the Tru64 +operating system: + + CXX libpcrecpp_la-pcrecpp.lo +cxx: Error: /usr/lib/cmplrs/cxx/V7.1-006/include/cxx/iosfwd, line 58: #error + directive: "cannot include iosfwd -- define __USE_STD_IOSTREAM to + override default - see section 7.1.2 of the C++ Using Guide" +#error "cannot include iosfwd -- define __USE_STD_IOSTREAM to override default +- see section 7.1.2 of the C++ Using Guide" + +This may be followed by other errors, complaining that 'namespace "std" has no +member'. The solution to this is to add the line + +#define __USE_STD_IOSTREAM 1 + +to the config.h file. + + +Using Sun's compilers for Solaris +--------------------------------- + +A user reports that the following configurations work on Solaris 9 sparcv9 and +Solaris 9 x86 (32-bit): + + Solaris 9 sparcv9: ./configure --disable-cpp CC=/bin/cc CFLAGS="-m64 -g" + Solaris 9 x86: ./configure --disable-cpp CC=/bin/cc CFLAGS="-g" + + +Using PCRE from MySQL +--------------------- + +On systems where both PCRE and MySQL are installed, it is possible to make use +of PCRE from within MySQL, as an alternative to the built-in pattern matching. +There is a web page that tells you how to do this: + + http://www.mysqludf.org/lib_mysqludf_preg/index.php + + +Making new tarballs +------------------- + +The command "make dist" creates three PCRE tarballs, in tar.gz, tar.bz2, and +zip formats. The command "make distcheck" does the same, but then does a trial +build of the new distribution to ensure that it works. + +If you have modified any of the man page sources in the doc directory, you +should first run the PrepareRelease script before making a distribution. This +script creates the .txt and HTML forms of the documentation from the man pages. + + +Testing PCRE +------------ + +To test the basic PCRE library on a Unix-like system, run the RunTest script. +There is another script called RunGrepTest that tests the options of the +pcregrep command. If the C++ wrapper library is built, three test programs +called pcrecpp_unittest, pcre_scanner_unittest, and pcre_stringpiece_unittest +are also built. When JIT support is enabled, another test program called +pcre_jit_test is built. + +Both the scripts and all the program tests are run if you obey "make check" or +"make test". For other environments, see the instructions in +NON-AUTOTOOLS-BUILD. + +The RunTest script runs the pcretest test program (which is documented in its +own man page) on each of the relevant testinput files in the testdata +directory, and compares the output with the contents of the corresponding +testoutput files. RunTest uses a file called testtry to hold the main output +from pcretest. Other files whose names begin with "test" are used as working +files in some tests. + +Some tests are relevant only when certain build-time options were selected. For +example, the tests for UTF-8/16/32 support are run only if --enable-utf was +used. RunTest outputs a comment when it skips a test. + +Many of the tests that are not skipped are run up to three times. The second +run forces pcre_study() to be called for all patterns except for a few in some +tests that are marked "never study" (see the pcretest program for how this is +done). If JIT support is available, the non-DFA tests are run a third time, +this time with a forced pcre_study() with the PCRE_STUDY_JIT_COMPILE option. +This testing can be suppressed by putting "nojit" on the RunTest command line. + +The entire set of tests is run once for each of the 8-bit, 16-bit and 32-bit +libraries that are enabled. If you want to run just one set of tests, call +RunTest with either the -8, -16 or -32 option. + +If valgrind is installed, you can run the tests under it by putting "valgrind" +on the RunTest command line. To run pcretest on just one or more specific test +files, give their numbers as arguments to RunTest, for example: + + RunTest 2 7 11 + +You can also specify ranges of tests such as 3-6 or 3- (meaning 3 to the +end), or a number preceded by ~ to exclude a test. For example: + + Runtest 3-15 ~10 + +This runs tests 3 to 15, excluding test 10, and just ~13 runs all the tests +except test 13. Whatever order the arguments are in, the tests are always run +in numerical order. + +You can also call RunTest with the single argument "list" to cause it to output +a list of tests. + +The first test file can be fed directly into the perltest.pl script to check +that Perl gives the same results. The only difference you should see is in the +first few lines, where the Perl version is given instead of the PCRE version. + +The second set of tests check pcre_fullinfo(), pcre_study(), +pcre_copy_substring(), pcre_get_substring(), pcre_get_substring_list(), error +detection, and run-time flags that are specific to PCRE, as well as the POSIX +wrapper API. It also uses the debugging flags to check some of the internals of +pcre_compile(). + +If you build PCRE with a locale setting that is not the standard C locale, the +character tables may be different (see next paragraph). In some cases, this may +cause failures in the second set of tests. For example, in a locale where the +isprint() function yields TRUE for characters in the range 128-255, the use of +[:isascii:] inside a character class defines a different set of characters, and +this shows up in this test as a difference in the compiled code, which is being +listed for checking. Where the comparison test output contains [\x00-\x7f] the +test will contain [\x00-\xff], and similarly in some other cases. This is not a +bug in PCRE. + +The third set of tests checks pcre_maketables(), the facility for building a +set of character tables for a specific locale and using them instead of the +default tables. The tests make use of the "fr_FR" (French) locale. Before +running the test, the script checks for the presence of this locale by running +the "locale" command. If that command fails, or if it doesn't include "fr_FR" +in the list of available locales, the third test cannot be run, and a comment +is output to say why. If running this test produces instances of the error + + ** Failed to set locale "fr_FR" + +in the comparison output, it means that locale is not available on your system, +despite being listed by "locale". This does not mean that PCRE is broken. + +[If you are trying to run this test on Windows, you may be able to get it to +work by changing "fr_FR" to "french" everywhere it occurs. Alternatively, use +RunTest.bat. The version of RunTest.bat included with PCRE 7.4 and above uses +Windows versions of test 2. More info on using RunTest.bat is included in the +document entitled NON-UNIX-USE.] + +The fourth and fifth tests check the UTF-8/16/32 support and error handling and +internal UTF features of PCRE that are not relevant to Perl, respectively. The +sixth and seventh tests do the same for Unicode character properties support. + +The eighth, ninth, and tenth tests check the pcre_dfa_exec() alternative +matching function, in non-UTF-8/16/32 mode, UTF-8/16/32 mode, and UTF-8/16/32 +mode with Unicode property support, respectively. + +The eleventh test checks some internal offsets and code size features; it is +run only when the default "link size" of 2 is set (in other cases the sizes +change) and when Unicode property support is enabled. + +The twelfth test is run only when JIT support is available, and the thirteenth +test is run only when JIT support is not available. They test some JIT-specific +features such as information output from pcretest about JIT compilation. + +The fourteenth, fifteenth, and sixteenth tests are run only in 8-bit mode, and +the seventeenth, eighteenth, and nineteenth tests are run only in 16/32-bit +mode. These are tests that generate different output in the two modes. They are +for general cases, UTF-8/16/32 support, and Unicode property support, +respectively. + +The twentieth test is run only in 16/32-bit mode. It tests some specific +16/32-bit features of the DFA matching engine. + +The twenty-first and twenty-second tests are run only in 16/32-bit mode, when +the link size is set to 2 for the 16-bit library. They test reloading +pre-compiled patterns. + +The twenty-third and twenty-fourth tests are run only in 16-bit mode. They are +for general cases, and UTF-16 support, respectively. + +The twenty-fifth and twenty-sixth tests are run only in 32-bit mode. They are +for general cases, and UTF-32 support, respectively. + + +Character tables +---------------- + +For speed, PCRE uses four tables for manipulating and identifying characters +whose code point values are less than 256. The final argument of the +pcre_compile() function is a pointer to a block of memory containing the +concatenated tables. A call to pcre_maketables() can be used to generate a set +of tables in the current locale. If the final argument for pcre_compile() is +passed as NULL, a set of default tables that is built into the binary is used. + +The source file called pcre_chartables.c contains the default set of tables. By +default, this is created as a copy of pcre_chartables.c.dist, which contains +tables for ASCII coding. However, if --enable-rebuild-chartables is specified +for ./configure, a different version of pcre_chartables.c is built by the +program dftables (compiled from dftables.c), which uses the ANSI C character +handling functions such as isalnum(), isalpha(), isupper(), islower(), etc. to +build the table sources. This means that the default C locale which is set for +your system will control the contents of these default tables. You can change +the default tables by editing pcre_chartables.c and then re-building PCRE. If +you do this, you should take care to ensure that the file does not get +automatically re-generated. The best way to do this is to move +pcre_chartables.c.dist out of the way and replace it with your customized +tables. + +When the dftables program is run as a result of --enable-rebuild-chartables, +it uses the default C locale that is set on your system. It does not pay +attention to the LC_xxx environment variables. In other words, it uses the +system's default locale rather than whatever the compiling user happens to have +set. If you really do want to build a source set of character tables in a +locale that is specified by the LC_xxx variables, you can run the dftables +program by hand with the -L option. For example: + + ./dftables -L pcre_chartables.c.special + +The first two 256-byte tables provide lower casing and case flipping functions, +respectively. The next table consists of three 32-byte bit maps which identify +digits, "word" characters, and white space, respectively. These are used when +building 32-byte bit maps that represent character classes for code points less +than 256. + +The final 256-byte table has bits indicating various character types, as +follows: + + 1 white space character + 2 letter + 4 decimal digit + 8 hexadecimal digit + 16 alphanumeric or '_' + 128 regular expression metacharacter or binary zero + +You should not alter the set of characters that contain the 128 bit, as that +will cause PCRE to malfunction. + + +File manifest +------------- + +The distribution should contain the files listed below. Where a file name is +given as pcre[16|32]_xxx it means that there are three files, one with the name +pcre_xxx, one with the name pcre16_xx, and a third with the name pcre32_xxx. + +(A) Source files of the PCRE library functions and their headers: + + dftables.c auxiliary program for building pcre_chartables.c + when --enable-rebuild-chartables is specified + + pcre_chartables.c.dist a default set of character tables that assume ASCII + coding; used, unless --enable-rebuild-chartables is + specified, by copying to pcre[16]_chartables.c + + pcreposix.c ) + pcre[16|32]_byte_order.c ) + pcre[16|32]_compile.c ) + pcre[16|32]_config.c ) + pcre[16|32]_dfa_exec.c ) + pcre[16|32]_exec.c ) + pcre[16|32]_fullinfo.c ) + pcre[16|32]_get.c ) sources for the functions in the library, + pcre[16|32]_globals.c ) and some internal functions that they use + pcre[16|32]_jit_compile.c ) + pcre[16|32]_maketables.c ) + pcre[16|32]_newline.c ) + pcre[16|32]_refcount.c ) + pcre[16|32]_string_utils.c ) + pcre[16|32]_study.c ) + pcre[16|32]_tables.c ) + pcre[16|32]_ucd.c ) + pcre[16|32]_version.c ) + pcre[16|32]_xclass.c ) + pcre_ord2utf8.c ) + pcre_valid_utf8.c ) + pcre16_ord2utf16.c ) + pcre16_utf16_utils.c ) + pcre16_valid_utf16.c ) + pcre32_utf32_utils.c ) + pcre32_valid_utf32.c ) + + pcre[16|32]_printint.c ) debugging function that is used by pcretest, + ) and can also be #included in pcre_compile() + + pcre.h.in template for pcre.h when built by "configure" + pcreposix.h header for the external POSIX wrapper API + pcre_internal.h header for internal use + sljit/* 16 files that make up the JIT compiler + ucp.h header for Unicode property handling + + config.h.in template for config.h, which is built by "configure" + + pcrecpp.h public header file for the C++ wrapper + pcrecpparg.h.in template for another C++ header file + pcre_scanner.h public header file for C++ scanner functions + pcrecpp.cc ) + pcre_scanner.cc ) source for the C++ wrapper library + + pcre_stringpiece.h.in template for pcre_stringpiece.h, the header for the + C++ stringpiece functions + pcre_stringpiece.cc source for the C++ stringpiece functions + +(B) Source files for programs that use PCRE: + + pcredemo.c simple demonstration of coding calls to PCRE + pcregrep.c source of a grep utility that uses PCRE + pcretest.c comprehensive test program + +(C) Auxiliary files: + + 132html script to turn "man" pages into HTML + AUTHORS information about the author of PCRE + ChangeLog log of changes to the code + CleanTxt script to clean nroff output for txt man pages + Detrail script to remove trailing spaces + HACKING some notes about the internals of PCRE + INSTALL generic installation instructions + LICENCE conditions for the use of PCRE + COPYING the same, using GNU's standard name + Makefile.in ) template for Unix Makefile, which is built by + ) "configure" + Makefile.am ) the automake input that was used to create + ) Makefile.in + NEWS important changes in this release + NON-UNIX-USE the previous name for NON-AUTOTOOLS-BUILD + NON-AUTOTOOLS-BUILD notes on building PCRE without using autotools + PrepareRelease script to make preparations for "make dist" + README this file + RunTest a Unix shell script for running tests + RunGrepTest a Unix shell script for pcregrep tests + aclocal.m4 m4 macros (generated by "aclocal") + config.guess ) files used by libtool, + config.sub ) used only when building a shared library + configure a configuring shell script (built by autoconf) + configure.ac ) the autoconf input that was used to build + ) "configure" and config.h + depcomp ) script to find program dependencies, generated by + ) automake + doc/*.3 man page sources for PCRE + doc/*.1 man page sources for pcregrep and pcretest + doc/index.html.src the base HTML page + doc/html/* HTML documentation + doc/pcre.txt plain text version of the man pages + doc/pcretest.txt plain text documentation of test program + doc/perltest.txt plain text documentation of Perl test program + install-sh a shell script for installing files + libpcre16.pc.in template for libpcre16.pc for pkg-config + libpcre32.pc.in template for libpcre32.pc for pkg-config + libpcre.pc.in template for libpcre.pc for pkg-config + libpcreposix.pc.in template for libpcreposix.pc for pkg-config + libpcrecpp.pc.in template for libpcrecpp.pc for pkg-config + ltmain.sh file used to build a libtool script + missing ) common stub for a few missing GNU programs while + ) installing, generated by automake + mkinstalldirs script for making install directories + perltest.pl Perl test program + pcre-config.in source of script which retains PCRE information + pcre_jit_test.c test program for the JIT compiler + pcrecpp_unittest.cc ) + pcre_scanner_unittest.cc ) test programs for the C++ wrapper + pcre_stringpiece_unittest.cc ) + testdata/testinput* test data for main library tests + testdata/testoutput* expected test results + testdata/grep* input and output for pcregrep tests + testdata/* other supporting test files + +(D) Auxiliary files for cmake support + + cmake/COPYING-CMAKE-SCRIPTS + cmake/FindPackageHandleStandardArgs.cmake + cmake/FindEditline.cmake + cmake/FindReadline.cmake + CMakeLists.txt + config-cmake.h.in + +(E) Auxiliary files for VPASCAL + + makevp.bat + makevp_c.txt + makevp_l.txt + pcregexp.pas + +(F) Auxiliary files for building PCRE "by hand" + + pcre.h.generic ) a version of the public PCRE header file + ) for use in non-"configure" environments + config.h.generic ) a version of config.h for use in non-"configure" + ) environments + +(F) Miscellaneous + + RunTest.bat a script for running tests under Windows + +Philip Hazel +Email local part: ph10 +Email domain: cam.ac.uk +Last updated: 17 January 2014 diff --git a/doc/html/index.html b/doc/html/index.html new file mode 100644 index 0000000..352c55d --- /dev/null +++ b/doc/html/index.html @@ -0,0 +1,185 @@ +<html> +<!-- This is a manually maintained file that is the root of the HTML version of + the PCRE documentation. When the HTML documents are built from the man + page versions, the entire doc/html directory is emptied, this file is then + copied into doc/html/index.html, and the remaining files therein are + created by the 132html script. +--> +<head> +<title>PCRE specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>Perl-compatible Regular Expressions (PCRE)</h1> +<p> +The HTML documentation for PCRE consists of a number of pages that are listed +below in alphabetical order. If you are new to PCRE, please read the first one +first. +</p> + +<table> +<tr><td><a href="pcre.html">pcre</a></td> + <td> Introductory page</td></tr> + +<tr><td><a href="pcre-config.html">pcre-config</a></td> + <td> Information about the installation configuration</td></tr> + +<tr><td><a href="pcre16.html">pcre16</a></td> + <td> Discussion of the 16-bit PCRE library</td></tr> + +<tr><td><a href="pcre32.html">pcre32</a></td> + <td> Discussion of the 32-bit PCRE library</td></tr> + +<tr><td><a href="pcreapi.html">pcreapi</a></td> + <td> PCRE's native API</td></tr> + +<tr><td><a href="pcrebuild.html">pcrebuild</a></td> + <td> Building PCRE</td></tr> + +<tr><td><a href="pcrecallout.html">pcrecallout</a></td> + <td> The <i>callout</i> facility</td></tr> + +<tr><td><a href="pcrecompat.html">pcrecompat</a></td> + <td> Compability with Perl</td></tr> + +<tr><td><a href="pcrecpp.html">pcrecpp</a></td> + <td> The C++ wrapper for the PCRE library</td></tr> + +<tr><td><a href="pcredemo.html">pcredemo</a></td> + <td> A demonstration C program that uses the PCRE library</td></tr> + +<tr><td><a href="pcregrep.html">pcregrep</a></td> + <td> The <b>pcregrep</b> command</td></tr> + +<tr><td><a href="pcrejit.html">pcrejit</a></td> + <td> Discussion of the just-in-time optimization support</td></tr> + +<tr><td><a href="pcrelimits.html">pcrelimits</a></td> + <td> Details of size and other limits</td></tr> + +<tr><td><a href="pcrematching.html">pcrematching</a></td> + <td> Discussion of the two matching algorithms</td></tr> + +<tr><td><a href="pcrepartial.html">pcrepartial</a></td> + <td> Using PCRE for partial matching</td></tr> + +<tr><td><a href="pcrepattern.html">pcrepattern</a></td> + <td> Specification of the regular expressions supported by PCRE</td></tr> + +<tr><td><a href="pcreperform.html">pcreperform</a></td> + <td> Some comments on performance</td></tr> + +<tr><td><a href="pcreposix.html">pcreposix</a></td> + <td> The POSIX API to the PCRE 8-bit library</td></tr> + +<tr><td><a href="pcreprecompile.html">pcreprecompile</a></td> + <td> How to save and re-use compiled patterns</td></tr> + +<tr><td><a href="pcresample.html">pcresample</a></td> + <td> Discussion of the pcredemo program</td></tr> + +<tr><td><a href="pcrestack.html">pcrestack</a></td> + <td> Discussion of PCRE's stack usage</td></tr> + +<tr><td><a href="pcresyntax.html">pcresyntax</a></td> + <td> Syntax quick-reference summary</td></tr> + +<tr><td><a href="pcretest.html">pcretest</a></td> + <td> The <b>pcretest</b> command for testing PCRE</td></tr> + +<tr><td><a href="pcreunicode.html">pcreunicode</a></td> + <td> Discussion of Unicode and UTF-8/UTF-16/UTF-32 support</td></tr> +</table> + +<p> +There are also individual pages that summarize the interface for each function +in the library. There is a single page for each triple of 8-bit/16-bit/32-bit +functions. +</p> + +<table> + +<tr><td><a href="pcre_assign_jit_stack.html">pcre_assign_jit_stack</a></td> + <td> Assign stack for JIT matching</td></tr> + +<tr><td><a href="pcre_compile.html">pcre_compile</a></td> + <td> Compile a regular expression</td></tr> + +<tr><td><a href="pcre_compile2.html">pcre_compile2</a></td> + <td> Compile a regular expression (alternate interface)</td></tr> + +<tr><td><a href="pcre_config.html">pcre_config</a></td> + <td> Show build-time configuration options</td></tr> + +<tr><td><a href="pcre_copy_named_substring.html">pcre_copy_named_substring</a></td> + <td> Extract named substring into given buffer</td></tr> + +<tr><td><a href="pcre_copy_substring.html">pcre_copy_substring</a></td> + <td> Extract numbered substring into given buffer</td></tr> + +<tr><td><a href="pcre_dfa_exec.html">pcre_dfa_exec</a></td> + <td> Match a compiled pattern to a subject string + (DFA algorithm; <i>not</i> Perl compatible)</td></tr> + +<tr><td><a href="pcre_exec.html">pcre_exec</a></td> + <td> Match a compiled pattern to a subject string + (Perl compatible)</td></tr> + +<tr><td><a href="pcre_free_study.html">pcre_free_study</a></td> + <td> Free study data</td></tr> + +<tr><td><a href="pcre_free_substring.html">pcre_free_substring</a></td> + <td> Free extracted substring</td></tr> + +<tr><td><a href="pcre_free_substring_list.html">pcre_free_substring_list</a></td> + <td> Free list of extracted substrings</td></tr> + +<tr><td><a href="pcre_fullinfo.html">pcre_fullinfo</a></td> + <td> Extract information about a pattern</td></tr> + +<tr><td><a href="pcre_get_named_substring.html">pcre_get_named_substring</a></td> + <td> Extract named substring into new memory</td></tr> + +<tr><td><a href="pcre_get_stringnumber.html">pcre_get_stringnumber</a></td> + <td> Convert captured string name to number</td></tr> + +<tr><td><a href="pcre_get_stringtable_entries.html">pcre_get_stringtable_entries</a></td> + <td> Find table entries for given string name</td></tr> + +<tr><td><a href="pcre_get_substring.html">pcre_get_substring</a></td> + <td> Extract numbered substring into new memory</td></tr> + +<tr><td><a href="pcre_get_substring_list.html">pcre_get_substring_list</a></td> + <td> Extract all substrings into new memory</td></tr> + +<tr><td><a href="pcre_jit_exec.html">pcre_jit_exec</a></td> + <td> Fast path interface to JIT matching</td></tr> + +<tr><td><a href="pcre_jit_stack_alloc.html">pcre_jit_stack_alloc</a></td> + <td> Create a stack for JIT matching</td></tr> + +<tr><td><a href="pcre_jit_stack_free.html">pcre_jit_stack_free</a></td> + <td> Free a JIT matching stack</td></tr> + +<tr><td><a href="pcre_maketables.html">pcre_maketables</a></td> + <td> Build character tables in current locale</td></tr> + +<tr><td><a href="pcre_pattern_to_host_byte_order.html">pcre_pattern_to_host_byte_order</a></td> + <td> Convert compiled pattern to host byte order if necessary</td></tr> + +<tr><td><a href="pcre_refcount.html">pcre_refcount</a></td> + <td> Maintain reference count in compiled pattern</td></tr> + +<tr><td><a href="pcre_study.html">pcre_study</a></td> + <td> Study a compiled pattern</td></tr> + +<tr><td><a href="pcre_utf16_to_host_byte_order.html">pcre_utf16_to_host_byte_order</a></td> + <td> Convert UTF-16 string to host byte order if necessary</td></tr> + +<tr><td><a href="pcre_utf32_to_host_byte_order.html">pcre_utf32_to_host_byte_order</a></td> + <td> Convert UTF-32 string to host byte order if necessary</td></tr> + +<tr><td><a href="pcre_version.html">pcre_version</a></td> + <td> Return PCRE version and release date</td></tr> +</table> + +</html> diff --git a/doc/html/pcre-config.html b/doc/html/pcre-config.html new file mode 100644 index 0000000..56a8060 --- /dev/null +++ b/doc/html/pcre-config.html @@ -0,0 +1,109 @@ +<html> +<head> +<title>pcre-config specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre-config man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> +<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> +<li><a name="TOC3" href="#SEC3">OPTIONS</a> +<li><a name="TOC4" href="#SEC4">SEE ALSO</a> +<li><a name="TOC5" href="#SEC5">AUTHOR</a> +<li><a name="TOC6" href="#SEC6">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> +<P> +<b>pcre-config [--prefix] [--exec-prefix] [--version] [--libs]</b> +<b> [--libs16] [--libs32] [--libs-cpp] [--libs-posix]</b> +<b> [--cflags] [--cflags-posix]</b> +</P> +<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> +<P> +<b>pcre-config</b> returns the configuration of the installed PCRE +libraries and the options required to compile a program to use them. Some of +the options apply only to the 8-bit, or 16-bit, or 32-bit libraries, +respectively, and are +not available if only one of those libraries has been built. If an unavailable +option is encountered, the "usage" information is output. +</P> +<br><a name="SEC3" href="#TOC1">OPTIONS</a><br> +<P> +<b>--prefix</b> +Writes the directory prefix used in the PCRE installation for architecture +independent files (<i>/usr</i> on many systems, <i>/usr/local</i> on some +systems) to the standard output. +</P> +<P> +<b>--exec-prefix</b> +Writes the directory prefix used in the PCRE installation for architecture +dependent files (normally the same as <b>--prefix</b>) to the standard output. +</P> +<P> +<b>--version</b> +Writes the version number of the installed PCRE libraries to the standard +output. +</P> +<P> +<b>--libs</b> +Writes to the standard output the command line options required to link +with the 8-bit PCRE library (<b>-lpcre</b> on many systems). +</P> +<P> +<b>--libs16</b> +Writes to the standard output the command line options required to link +with the 16-bit PCRE library (<b>-lpcre16</b> on many systems). +</P> +<P> +<b>--libs32</b> +Writes to the standard output the command line options required to link +with the 32-bit PCRE library (<b>-lpcre32</b> on many systems). +</P> +<P> +<b>--libs-cpp</b> +Writes to the standard output the command line options required to link with +PCRE's C++ wrapper library (<b>-lpcrecpp</b> <b>-lpcre</b> on many +systems). +</P> +<P> +<b>--libs-posix</b> +Writes to the standard output the command line options required to link with +PCRE's POSIX API wrapper library (<b>-lpcreposix</b> <b>-lpcre</b> on many +systems). +</P> +<P> +<b>--cflags</b> +Writes to the standard output the command line options required to compile +files that use PCRE (this may include some <b>-I</b> options, but is blank on +many systems). +</P> +<P> +<b>--cflags-posix</b> +Writes to the standard output the command line options required to compile +files that use PCRE's POSIX API wrapper library (this may include some <b>-I</b> +options, but is blank on many systems). +</P> +<br><a name="SEC4" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcre(3)</b> +</P> +<br><a name="SEC5" href="#TOC1">AUTHOR</a><br> +<P> +This manual page was originally written by Mark Baker for the Debian GNU/Linux +system. It has been subsequently revised as a generic PCRE man page. +</P> +<br><a name="SEC6" href="#TOC1">REVISION</a><br> +<P> +Last updated: 24 June 2012 +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre.html b/doc/html/pcre.html new file mode 100644 index 0000000..c2b29aa --- /dev/null +++ b/doc/html/pcre.html @@ -0,0 +1,213 @@ +<html> +<head> +<title>pcre specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">INTRODUCTION</a> +<li><a name="TOC2" href="#SEC2">SECURITY CONSIDERATIONS</a> +<li><a name="TOC3" href="#SEC3">USER DOCUMENTATION</a> +<li><a name="TOC4" href="#SEC4">AUTHOR</a> +<li><a name="TOC5" href="#SEC5">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br> +<P> +The PCRE library is a set of functions that implement regular expression +pattern matching using the same syntax and semantics as Perl, with just a few +differences. Some features that appeared in Python and PCRE before they +appeared in Perl are also available using the Python syntax, there is some +support for one or two .NET and Oniguruma syntax items, and there is an option +for requesting some minor changes that give better JavaScript compatibility. +</P> +<P> +Starting with release 8.30, it is possible to compile two separate PCRE +libraries: the original, which supports 8-bit character strings (including +UTF-8 strings), and a second library that supports 16-bit character strings +(including UTF-16 strings). The build process allows either one or both to be +built. The majority of the work to make this possible was done by Zoltan +Herczeg. +</P> +<P> +Starting with release 8.32 it is possible to compile a third separate PCRE +library that supports 32-bit character strings (including UTF-32 strings). The +build process allows any combination of the 8-, 16- and 32-bit libraries. The +work to make this possible was done by Christian Persch. +</P> +<P> +The three libraries contain identical sets of functions, except that the names +in the 16-bit library start with <b>pcre16_</b> instead of <b>pcre_</b>, and the +names in the 32-bit library start with <b>pcre32_</b> instead of <b>pcre_</b>. To +avoid over-complication and reduce the documentation maintenance load, most of +the documentation describes the 8-bit library, with the differences for the +16-bit and 32-bit libraries described separately in the +<a href="pcre16.html"><b>pcre16</b></a> +and +<a href="pcre32.html"><b>pcre32</b></a> +pages. References to functions or structures of the form <i>pcre[16|32]_xxx</i> +should be read as meaning "<i>pcre_xxx</i> when using the 8-bit library, +<i>pcre16_xxx</i> when using the 16-bit library, or <i>pcre32_xxx</i> when using +the 32-bit library". +</P> +<P> +The current implementation of PCRE corresponds approximately with Perl 5.12, +including support for UTF-8/16/32 encoded strings and Unicode general category +properties. However, UTF-8/16/32 and Unicode support has to be explicitly +enabled; it is not the default. The Unicode tables correspond to Unicode +release 6.3.0. +</P> +<P> +In addition to the Perl-compatible matching function, PCRE contains an +alternative function that matches the same compiled patterns in a different +way. In certain circumstances, the alternative function has some advantages. +For a discussion of the two matching algorithms, see the +<a href="pcrematching.html"><b>pcrematching</b></a> +page. +</P> +<P> +PCRE is written in C and released as a C library. A number of people have +written wrappers and interfaces of various kinds. In particular, Google Inc. +have provided a comprehensive C++ wrapper for the 8-bit library. This is now +included as part of the PCRE distribution. The +<a href="pcrecpp.html"><b>pcrecpp</b></a> +page has details of this interface. Other people's contributions can be found +in the <i>Contrib</i> directory at the primary FTP site, which is: +<a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre</a> +</P> +<P> +Details of exactly which Perl regular expression features are and are not +supported by PCRE are given in separate documents. See the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +and +<a href="pcrecompat.html"><b>pcrecompat</b></a> +pages. There is a syntax summary in the +<a href="pcresyntax.html"><b>pcresyntax</b></a> +page. +</P> +<P> +Some features of PCRE can be included, excluded, or changed when the library is +built. The +<a href="pcre_config.html"><b>pcre_config()</b></a> +function makes it possible for a client to discover which features are +available. The features themselves are described in the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +page. Documentation about building PCRE for various operating systems can be +found in the +<a href="README.txt"><b>README</b></a> +and +<a href="NON-AUTOTOOLS-BUILD.txt"><b>NON-AUTOTOOLS_BUILD</b></a> +files in the source distribution. +</P> +<P> +The libraries contains a number of undocumented internal functions and data +tables that are used by more than one of the exported external functions, but +which are not intended for use by external callers. Their names all begin with +"_pcre_" or "_pcre16_" or "_pcre32_", which hopefully will not provoke any name +clashes. In some environments, it is possible to control which external symbols +are exported when a shared library is built, and in these cases the +undocumented symbols are not exported. +</P> +<br><a name="SEC2" href="#TOC1">SECURITY CONSIDERATIONS</a><br> +<P> +If you are using PCRE in a non-UTF application that permits users to supply +arbitrary patterns for compilation, you should be aware of a feature that +allows users to turn on UTF support from within a pattern, provided that PCRE +was built with UTF support. For example, an 8-bit pattern that begins with +"(*UTF8)" or "(*UTF)" turns on UTF-8 mode, which interprets patterns and +subjects as strings of UTF-8 characters instead of individual 8-bit characters. +This causes both the pattern and any data against which it is matched to be +checked for UTF-8 validity. If the data string is very long, such a check might +use sufficiently many resources as to cause your application to lose +performance. +</P> +<P> +One way of guarding against this possibility is to use the +<b>pcre_fullinfo()</b> function to check the compiled pattern's options for UTF. +Alternatively, from release 8.33, you can set the PCRE_NEVER_UTF option at +compile time. This causes an compile time error if a pattern contains a +UTF-setting sequence. +</P> +<P> +If your application is one that supports UTF, be aware that validity checking +can take time. If the same data string is to be matched many times, you can use +the PCRE_NO_UTF[8|16|32]_CHECK option for the second and subsequent matches to +save redundant checks. +</P> +<P> +Another way that performance can be hit is by running a pattern that has a very +large search tree against a string that will never match. Nested unlimited +repeats in a pattern are a common example. PCRE provides some protection +against this: see the PCRE_EXTRA_MATCH_LIMIT feature in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page. +</P> +<br><a name="SEC3" href="#TOC1">USER DOCUMENTATION</a><br> +<P> +The user documentation for PCRE comprises a number of different sections. In +the "man" format, each of these is a separate "man page". In the HTML format, +each is a separate page, linked from the index page. In the plain text format, +the descriptions of the <b>pcregrep</b> and <b>pcretest</b> programs are in files +called <b>pcregrep.txt</b> and <b>pcretest.txt</b>, respectively. The remaining +sections, except for the <b>pcredemo</b> section (which is a program listing), +are concatenated in <b>pcre.txt</b>, for ease of searching. The sections are as +follows: +<pre> + pcre this document + pcre-config show PCRE installation configuration information + pcre16 details of the 16-bit library + pcre32 details of the 32-bit library + pcreapi details of PCRE's native C API + pcrebuild building PCRE + pcrecallout details of the callout feature + pcrecompat discussion of Perl compatibility + pcrecpp details of the C++ wrapper for the 8-bit library + pcredemo a demonstration C program that uses PCRE + pcregrep description of the <b>pcregrep</b> command (8-bit only) + pcrejit discussion of the just-in-time optimization support + pcrelimits details of size and other limits + pcrematching discussion of the two matching algorithms + pcrepartial details of the partial matching facility + pcrepattern syntax and semantics of supported regular expressions + pcreperform discussion of performance issues + pcreposix the POSIX-compatible C API for the 8-bit library + pcreprecompile details of saving and re-using precompiled patterns + pcresample discussion of the pcredemo program + pcrestack discussion of stack usage + pcresyntax quick syntax reference + pcretest description of the <b>pcretest</b> testing command + pcreunicode discussion of Unicode and UTF-8/16/32 support +</pre> +In the "man" and HTML formats, there is also a short page for each C library +function, listing its arguments and results. +</P> +<br><a name="SEC4" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<P> +Putting an actual email address here seems to have been a spam magnet, so I've +taken it away. If you want to email me, use my two initials, followed by the +two digits 10, at the domain cam.ac.uk. +</P> +<br><a name="SEC5" href="#TOC1">REVISION</a><br> +<P> +Last updated: 08 January 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre16.html b/doc/html/pcre16.html new file mode 100644 index 0000000..f00859f --- /dev/null +++ b/doc/html/pcre16.html @@ -0,0 +1,384 @@ +<html> +<head> +<title>pcre16 specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre16 man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE 16-BIT API BASIC FUNCTIONS</a> +<li><a name="TOC2" href="#SEC2">PCRE 16-BIT API STRING EXTRACTION FUNCTIONS</a> +<li><a name="TOC3" href="#SEC3">PCRE 16-BIT API AUXILIARY FUNCTIONS</a> +<li><a name="TOC4" href="#SEC4">PCRE 16-BIT API INDIRECTED FUNCTIONS</a> +<li><a name="TOC5" href="#SEC5">PCRE 16-BIT API 16-BIT-ONLY FUNCTION</a> +<li><a name="TOC6" href="#SEC6">THE PCRE 16-BIT LIBRARY</a> +<li><a name="TOC7" href="#SEC7">THE HEADER FILE</a> +<li><a name="TOC8" href="#SEC8">THE LIBRARY NAME</a> +<li><a name="TOC9" href="#SEC9">STRING TYPES</a> +<li><a name="TOC10" href="#SEC10">STRUCTURE TYPES</a> +<li><a name="TOC11" href="#SEC11">16-BIT FUNCTIONS</a> +<li><a name="TOC12" href="#SEC12">SUBJECT STRING OFFSETS</a> +<li><a name="TOC13" href="#SEC13">NAMED SUBPATTERNS</a> +<li><a name="TOC14" href="#SEC14">OPTION NAMES</a> +<li><a name="TOC15" href="#SEC15">CHARACTER CODES</a> +<li><a name="TOC16" href="#SEC16">ERROR NAMES</a> +<li><a name="TOC17" href="#SEC17">ERROR TEXTS</a> +<li><a name="TOC18" href="#SEC18">CALLOUTS</a> +<li><a name="TOC19" href="#SEC19">TESTING</a> +<li><a name="TOC20" href="#SEC20">NOT SUPPORTED IN 16-BIT MODE</a> +<li><a name="TOC21" href="#SEC21">AUTHOR</a> +<li><a name="TOC22" href="#SEC22">REVISION</a> +</ul> +<P> +<b>#include <pcre.h></b> +</P> +<br><a name="SEC1" href="#TOC1">PCRE 16-BIT API BASIC FUNCTIONS</a><br> +<P> +<b>pcre16 *pcre16_compile(PCRE_SPTR16 <i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre16 *pcre16_compile2(PCRE_SPTR16 <i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre16_extra *pcre16_study(const pcre16 *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +<br> +<br> +<b>void pcre16_free_study(pcre16_extra *<i>extra</i>);</b> +<br> +<br> +<b>int pcre16_exec(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +<br> +<br> +<b>int pcre16_dfa_exec(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +</P> +<br><a name="SEC2" href="#TOC1">PCRE 16-BIT API STRING EXTRACTION FUNCTIONS</a><br> +<P> +<b>int pcre16_copy_named_substring(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR16 <i>stringname</i>,</b> +<b> PCRE_UCHAR16 *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre16_copy_substring(PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, PCRE_UCHAR16 *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre16_get_named_substring(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR16 <i>stringname</i>,</b> +<b> PCRE_SPTR16 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre16_get_stringnumber(const pcre16 *<i>code</i>,</b> +<b>" PCRE_SPTR16 <i>name</i>);</b> +<br> +<br> +<b>int pcre16_get_stringtable_entries(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>name</i>, PCRE_UCHAR16 **<i>first</i>, PCRE_UCHAR16 **<i>last</i>);</b> +<br> +<br> +<b>int pcre16_get_substring(PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> PCRE_SPTR16 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre16_get_substring_list(PCRE_SPTR16 <i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, PCRE_SPTR16 **<i>listptr</i>);</b> +<br> +<br> +<b>void pcre16_free_substring(PCRE_SPTR16 <i>stringptr</i>);</b> +<br> +<br> +<b>void pcre16_free_substring_list(PCRE_SPTR16 *<i>stringptr</i>);</b> +</P> +<br><a name="SEC3" href="#TOC1">PCRE 16-BIT API AUXILIARY FUNCTIONS</a><br> +<P> +<b>pcre16_jit_stack *pcre16_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b> +<br> +<br> +<b>void pcre16_jit_stack_free(pcre16_jit_stack *<i>stack</i>);</b> +<br> +<br> +<b>void pcre16_assign_jit_stack(pcre16_extra *<i>extra</i>,</b> +<b> pcre16_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> +<b>const unsigned char *pcre16_maketables(void);</b> +<br> +<br> +<b>int pcre16_fullinfo(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>int pcre16_refcount(pcre16 *<i>code</i>, int <i>adjust</i>);</b> +<br> +<br> +<b>int pcre16_config(int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>const char *pcre16_version(void);</b> +<br> +<br> +<b>int pcre16_pattern_to_host_byte_order(pcre16 *<i>code</i>,</b> +<b> pcre16_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +</P> +<br><a name="SEC4" href="#TOC1">PCRE 16-BIT API INDIRECTED FUNCTIONS</a><br> +<P> +<b>void *(*pcre16_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre16_free)(void *);</b> +<br> +<br> +<b>void *(*pcre16_stack_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre16_stack_free)(void *);</b> +<br> +<br> +<b>int (*pcre16_callout)(pcre16_callout_block *);</b> +</P> +<br><a name="SEC5" href="#TOC1">PCRE 16-BIT API 16-BIT-ONLY FUNCTION</a><br> +<P> +<b>int pcre16_utf16_to_host_byte_order(PCRE_UCHAR16 *<i>output</i>,</b> +<b> PCRE_SPTR16 <i>input</i>, int <i>length</i>, int *<i>byte_order</i>,</b> +<b> int <i>keep_boms</i>);</b> +</P> +<br><a name="SEC6" href="#TOC1">THE PCRE 16-BIT LIBRARY</a><br> +<P> +Starting with release 8.30, it is possible to compile a PCRE library that +supports 16-bit character strings, including UTF-16 strings, as well as or +instead of the original 8-bit library. The majority of the work to make this +possible was done by Zoltan Herczeg. The two libraries contain identical sets +of functions, used in exactly the same way. Only the names of the functions and +the data types of their arguments and results are different. To avoid +over-complication and reduce the documentation maintenance load, most of the +PCRE documentation describes the 8-bit library, with only occasional references +to the 16-bit library. This page describes what is different when you use the +16-bit library. +</P> +<P> +WARNING: A single application can be linked with both libraries, but you must +take care when processing any particular pattern to use functions from just one +library. For example, if you want to study a pattern that was compiled with +<b>pcre16_compile()</b>, you must do so with <b>pcre16_study()</b>, not +<b>pcre_study()</b>, and you must free the study data with +<b>pcre16_free_study()</b>. +</P> +<br><a name="SEC7" href="#TOC1">THE HEADER FILE</a><br> +<P> +There is only one header file, <b>pcre.h</b>. It contains prototypes for all the +functions in all libraries, as well as definitions of flags, structures, error +codes, etc. +</P> +<br><a name="SEC8" href="#TOC1">THE LIBRARY NAME</a><br> +<P> +In Unix-like systems, the 16-bit library is called <b>libpcre16</b>, and can +normally be accesss by adding <b>-lpcre16</b> to the command for linking an +application that uses PCRE. +</P> +<br><a name="SEC9" href="#TOC1">STRING TYPES</a><br> +<P> +In the 8-bit library, strings are passed to PCRE library functions as vectors +of bytes with the C type "char *". In the 16-bit library, strings are passed as +vectors of unsigned 16-bit quantities. The macro PCRE_UCHAR16 specifies an +appropriate data type, and PCRE_SPTR16 is defined as "const PCRE_UCHAR16 *". In +very many environments, "short int" is a 16-bit data type. When PCRE is built, +it defines PCRE_UCHAR16 as "unsigned short int", but checks that it really is a +16-bit data type. If it is not, the build fails with an error message telling +the maintainer to modify the definition appropriately. +</P> +<br><a name="SEC10" href="#TOC1">STRUCTURE TYPES</a><br> +<P> +The types of the opaque structures that are used for compiled 16-bit patterns +and JIT stacks are <b>pcre16</b> and <b>pcre16_jit_stack</b> respectively. The +type of the user-accessible structure that is returned by <b>pcre16_study()</b> +is <b>pcre16_extra</b>, and the type of the structure that is used for passing +data to a callout function is <b>pcre16_callout_block</b>. These structures +contain the same fields, with the same names, as their 8-bit counterparts. The +only difference is that pointers to character strings are 16-bit instead of +8-bit types. +</P> +<br><a name="SEC11" href="#TOC1">16-BIT FUNCTIONS</a><br> +<P> +For every function in the 8-bit library there is a corresponding function in +the 16-bit library with a name that starts with <b>pcre16_</b> instead of +<b>pcre_</b>. The prototypes are listed above. In addition, there is one extra +function, <b>pcre16_utf16_to_host_byte_order()</b>. This is a utility function +that converts a UTF-16 character string to host byte order if necessary. The +other 16-bit functions expect the strings they are passed to be in host byte +order. +</P> +<P> +The <i>input</i> and <i>output</i> arguments of +<b>pcre16_utf16_to_host_byte_order()</b> may point to the same address, that is, +conversion in place is supported. The output buffer must be at least as long as +the input. +</P> +<P> +The <i>length</i> argument specifies the number of 16-bit data units in the +input string; a negative value specifies a zero-terminated string. +</P> +<P> +If <i>byte_order</i> is NULL, it is assumed that the string starts off in host +byte order. This may be changed by byte-order marks (BOMs) anywhere in the +string (commonly as the first character). +</P> +<P> +If <i>byte_order</i> is not NULL, a non-zero value of the integer to which it +points means that the input starts off in host byte order, otherwise the +opposite order is assumed. Again, BOMs in the string can change this. The final +byte order is passed back at the end of processing. +</P> +<P> +If <i>keep_boms</i> is not zero, byte-order mark characters (0xfeff) are copied +into the output string. Otherwise they are discarded. +</P> +<P> +The result of the function is the number of 16-bit units placed into the output +buffer, including the zero terminator if the string was zero-terminated. +</P> +<br><a name="SEC12" href="#TOC1">SUBJECT STRING OFFSETS</a><br> +<P> +The lengths and starting offsets of subject strings must be specified in 16-bit +data units, and the offsets within subject strings that are returned by the +matching functions are in also 16-bit units rather than bytes. +</P> +<br><a name="SEC13" href="#TOC1">NAMED SUBPATTERNS</a><br> +<P> +The name-to-number translation table that is maintained for named subpatterns +uses 16-bit characters. The <b>pcre16_get_stringtable_entries()</b> function +returns the length of each entry in the table as the number of 16-bit data +units. +</P> +<br><a name="SEC14" href="#TOC1">OPTION NAMES</a><br> +<P> +There are two new general option names, PCRE_UTF16 and PCRE_NO_UTF16_CHECK, +which correspond to PCRE_UTF8 and PCRE_NO_UTF8_CHECK in the 8-bit library. In +fact, these new options define the same bits in the options word. There is a +discussion about the +<a href="pcreunicode.html#utf16strings">validity of UTF-16 strings</a> +in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. +</P> +<P> +For the <b>pcre16_config()</b> function there is an option PCRE_CONFIG_UTF16 +that returns 1 if UTF-16 support is configured, otherwise 0. If this option is +given to <b>pcre_config()</b> or <b>pcre32_config()</b>, or if the +PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF32 option is given to <b>pcre16_config()</b>, +the result is the PCRE_ERROR_BADOPTION error. +</P> +<br><a name="SEC15" href="#TOC1">CHARACTER CODES</a><br> +<P> +In 16-bit mode, when PCRE_UTF16 is not set, character values are treated in the +same way as in 8-bit, non UTF-8 mode, except, of course, that they can range +from 0 to 0xffff instead of 0 to 0xff. Character types for characters less than +0xff can therefore be influenced by the locale in the same way as before. +Characters greater than 0xff have only one case, and no "type" (such as letter +or digit). +</P> +<P> +In UTF-16 mode, the character code is Unicode, in the range 0 to 0x10ffff, with +the exception of values in the range 0xd800 to 0xdfff because those are +"surrogate" values that are used in pairs to encode values greater than 0xffff. +</P> +<P> +A UTF-16 string can indicate its endianness by special code knows as a +byte-order mark (BOM). The PCRE functions do not handle this, expecting strings +to be in host byte order. A utility function called +<b>pcre16_utf16_to_host_byte_order()</b> is provided to help with this (see +above). +</P> +<br><a name="SEC16" href="#TOC1">ERROR NAMES</a><br> +<P> +The errors PCRE_ERROR_BADUTF16_OFFSET and PCRE_ERROR_SHORTUTF16 correspond to +their 8-bit counterparts. The error PCRE_ERROR_BADMODE is given when a compiled +pattern is passed to a function that processes patterns in the other +mode, for example, if a pattern compiled with <b>pcre_compile()</b> is passed to +<b>pcre16_exec()</b>. +</P> +<P> +There are new error codes whose names begin with PCRE_UTF16_ERR for invalid +UTF-16 strings, corresponding to the PCRE_UTF8_ERR codes for UTF-8 strings that +are described in the section entitled +<a href="pcreapi.html#badutf8reasons">"Reason codes for invalid UTF-8 strings"</a> +in the main +<a href="pcreapi.html"><b>pcreapi</b></a> +page. The UTF-16 errors are: +<pre> + PCRE_UTF16_ERR1 Missing low surrogate at end of string + PCRE_UTF16_ERR2 Invalid low surrogate follows high surrogate + PCRE_UTF16_ERR3 Isolated low surrogate + PCRE_UTF16_ERR4 Non-character +</PRE> +</P> +<br><a name="SEC17" href="#TOC1">ERROR TEXTS</a><br> +<P> +If there is an error while compiling a pattern, the error text that is passed +back by <b>pcre16_compile()</b> or <b>pcre16_compile2()</b> is still an 8-bit +character string, zero-terminated. +</P> +<br><a name="SEC18" href="#TOC1">CALLOUTS</a><br> +<P> +The <i>subject</i> and <i>mark</i> fields in the callout block that is passed to +a callout function point to 16-bit vectors. +</P> +<br><a name="SEC19" href="#TOC1">TESTING</a><br> +<P> +The <b>pcretest</b> program continues to operate with 8-bit input and output +files, but it can be used for testing the 16-bit library. If it is run with the +command line option <b>-16</b>, patterns and subject strings are converted from +8-bit to 16-bit before being passed to PCRE, and the 16-bit library functions +are used instead of the 8-bit ones. Returned 16-bit strings are converted to +8-bit for output. If both the 8-bit and the 32-bit libraries were not compiled, +<b>pcretest</b> defaults to 16-bit and the <b>-16</b> option is ignored. +</P> +<P> +When PCRE is being built, the <b>RunTest</b> script that is called by "make +check" uses the <b>pcretest</b> <b>-C</b> option to discover which of the 8-bit, +16-bit and 32-bit libraries has been built, and runs the tests appropriately. +</P> +<br><a name="SEC20" href="#TOC1">NOT SUPPORTED IN 16-BIT MODE</a><br> +<P> +Not all the features of the 8-bit library are available with the 16-bit +library. The C++ and POSIX wrapper functions support only the 8-bit library, +and the <b>pcregrep</b> program is at present 8-bit only. +</P> +<br><a name="SEC21" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC22" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 May 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre32.html b/doc/html/pcre32.html new file mode 100644 index 0000000..f96876e --- /dev/null +++ b/doc/html/pcre32.html @@ -0,0 +1,382 @@ +<html> +<head> +<title>pcre32 specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre32 man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE 32-BIT API BASIC FUNCTIONS</a> +<li><a name="TOC2" href="#SEC2">PCRE 32-BIT API STRING EXTRACTION FUNCTIONS</a> +<li><a name="TOC3" href="#SEC3">PCRE 32-BIT API AUXILIARY FUNCTIONS</a> +<li><a name="TOC4" href="#SEC4">PCRE 32-BIT API INDIRECTED FUNCTIONS</a> +<li><a name="TOC5" href="#SEC5">PCRE 32-BIT API 32-BIT-ONLY FUNCTION</a> +<li><a name="TOC6" href="#SEC6">THE PCRE 32-BIT LIBRARY</a> +<li><a name="TOC7" href="#SEC7">THE HEADER FILE</a> +<li><a name="TOC8" href="#SEC8">THE LIBRARY NAME</a> +<li><a name="TOC9" href="#SEC9">STRING TYPES</a> +<li><a name="TOC10" href="#SEC10">STRUCTURE TYPES</a> +<li><a name="TOC11" href="#SEC11">32-BIT FUNCTIONS</a> +<li><a name="TOC12" href="#SEC12">SUBJECT STRING OFFSETS</a> +<li><a name="TOC13" href="#SEC13">NAMED SUBPATTERNS</a> +<li><a name="TOC14" href="#SEC14">OPTION NAMES</a> +<li><a name="TOC15" href="#SEC15">CHARACTER CODES</a> +<li><a name="TOC16" href="#SEC16">ERROR NAMES</a> +<li><a name="TOC17" href="#SEC17">ERROR TEXTS</a> +<li><a name="TOC18" href="#SEC18">CALLOUTS</a> +<li><a name="TOC19" href="#SEC19">TESTING</a> +<li><a name="TOC20" href="#SEC20">NOT SUPPORTED IN 32-BIT MODE</a> +<li><a name="TOC21" href="#SEC21">AUTHOR</a> +<li><a name="TOC22" href="#SEC22">REVISION</a> +</ul> +<P> +<b>#include <pcre.h></b> +</P> +<br><a name="SEC1" href="#TOC1">PCRE 32-BIT API BASIC FUNCTIONS</a><br> +<P> +<b>pcre32 *pcre32_compile(PCRE_SPTR32 <i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre32 *pcre32_compile2(PCRE_SPTR32 <i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre32_extra *pcre32_study(const pcre32 *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +<br> +<br> +<b>void pcre32_free_study(pcre32_extra *<i>extra</i>);</b> +<br> +<br> +<b>int pcre32_exec(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +<br> +<br> +<b>int pcre32_dfa_exec(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +</P> +<br><a name="SEC2" href="#TOC1">PCRE 32-BIT API STRING EXTRACTION FUNCTIONS</a><br> +<P> +<b>int pcre32_copy_named_substring(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR32 <i>stringname</i>,</b> +<b> PCRE_UCHAR32 *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre32_copy_substring(PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, PCRE_UCHAR32 *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre32_get_named_substring(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR32 <i>stringname</i>,</b> +<b> PCRE_SPTR32 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre32_get_stringnumber(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>name</i>);</b> +<br> +<br> +<b>int pcre32_get_stringtable_entries(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>name</i>, PCRE_UCHAR32 **<i>first</i>, PCRE_UCHAR32 **<i>last</i>);</b> +<br> +<br> +<b>int pcre32_get_substring(PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> PCRE_SPTR32 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre32_get_substring_list(PCRE_SPTR32 <i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, PCRE_SPTR32 **<i>listptr</i>);</b> +<br> +<br> +<b>void pcre32_free_substring(PCRE_SPTR32 <i>stringptr</i>);</b> +<br> +<br> +<b>void pcre32_free_substring_list(PCRE_SPTR32 *<i>stringptr</i>);</b> +</P> +<br><a name="SEC3" href="#TOC1">PCRE 32-BIT API AUXILIARY FUNCTIONS</a><br> +<P> +<b>pcre32_jit_stack *pcre32_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b> +<br> +<br> +<b>void pcre32_jit_stack_free(pcre32_jit_stack *<i>stack</i>);</b> +<br> +<br> +<b>void pcre32_assign_jit_stack(pcre32_extra *<i>extra</i>,</b> +<b> pcre32_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> +<b>const unsigned char *pcre32_maketables(void);</b> +<br> +<br> +<b>int pcre32_fullinfo(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>int pcre32_refcount(pcre32 *<i>code</i>, int <i>adjust</i>);</b> +<br> +<br> +<b>int pcre32_config(int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>const char *pcre32_version(void);</b> +<br> +<br> +<b>int pcre32_pattern_to_host_byte_order(pcre32 *<i>code</i>,</b> +<b> pcre32_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +</P> +<br><a name="SEC4" href="#TOC1">PCRE 32-BIT API INDIRECTED FUNCTIONS</a><br> +<P> +<b>void *(*pcre32_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre32_free)(void *);</b> +<br> +<br> +<b>void *(*pcre32_stack_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre32_stack_free)(void *);</b> +<br> +<br> +<b>int (*pcre32_callout)(pcre32_callout_block *);</b> +</P> +<br><a name="SEC5" href="#TOC1">PCRE 32-BIT API 32-BIT-ONLY FUNCTION</a><br> +<P> +<b>int pcre32_utf32_to_host_byte_order(PCRE_UCHAR32 *<i>output</i>,</b> +<b> PCRE_SPTR32 <i>input</i>, int <i>length</i>, int *<i>byte_order</i>,</b> +<b> int <i>keep_boms</i>);</b> +</P> +<br><a name="SEC6" href="#TOC1">THE PCRE 32-BIT LIBRARY</a><br> +<P> +Starting with release 8.32, it is possible to compile a PCRE library that +supports 32-bit character strings, including UTF-32 strings, as well as or +instead of the original 8-bit library. This work was done by Christian Persch, +based on the work done by Zoltan Herczeg for the 16-bit library. All three +libraries contain identical sets of functions, used in exactly the same way. +Only the names of the functions and the data types of their arguments and +results are different. To avoid over-complication and reduce the documentation +maintenance load, most of the PCRE documentation describes the 8-bit library, +with only occasional references to the 16-bit and 32-bit libraries. This page +describes what is different when you use the 32-bit library. +</P> +<P> +WARNING: A single application can be linked with all or any of the three +libraries, but you must take care when processing any particular pattern +to use functions from just one library. For example, if you want to study +a pattern that was compiled with <b>pcre32_compile()</b>, you must do so +with <b>pcre32_study()</b>, not <b>pcre_study()</b>, and you must free the +study data with <b>pcre32_free_study()</b>. +</P> +<br><a name="SEC7" href="#TOC1">THE HEADER FILE</a><br> +<P> +There is only one header file, <b>pcre.h</b>. It contains prototypes for all the +functions in all libraries, as well as definitions of flags, structures, error +codes, etc. +</P> +<br><a name="SEC8" href="#TOC1">THE LIBRARY NAME</a><br> +<P> +In Unix-like systems, the 32-bit library is called <b>libpcre32</b>, and can +normally be accesss by adding <b>-lpcre32</b> to the command for linking an +application that uses PCRE. +</P> +<br><a name="SEC9" href="#TOC1">STRING TYPES</a><br> +<P> +In the 8-bit library, strings are passed to PCRE library functions as vectors +of bytes with the C type "char *". In the 32-bit library, strings are passed as +vectors of unsigned 32-bit quantities. The macro PCRE_UCHAR32 specifies an +appropriate data type, and PCRE_SPTR32 is defined as "const PCRE_UCHAR32 *". In +very many environments, "unsigned int" is a 32-bit data type. When PCRE is +built, it defines PCRE_UCHAR32 as "unsigned int", but checks that it really is +a 32-bit data type. If it is not, the build fails with an error message telling +the maintainer to modify the definition appropriately. +</P> +<br><a name="SEC10" href="#TOC1">STRUCTURE TYPES</a><br> +<P> +The types of the opaque structures that are used for compiled 32-bit patterns +and JIT stacks are <b>pcre32</b> and <b>pcre32_jit_stack</b> respectively. The +type of the user-accessible structure that is returned by <b>pcre32_study()</b> +is <b>pcre32_extra</b>, and the type of the structure that is used for passing +data to a callout function is <b>pcre32_callout_block</b>. These structures +contain the same fields, with the same names, as their 8-bit counterparts. The +only difference is that pointers to character strings are 32-bit instead of +8-bit types. +</P> +<br><a name="SEC11" href="#TOC1">32-BIT FUNCTIONS</a><br> +<P> +For every function in the 8-bit library there is a corresponding function in +the 32-bit library with a name that starts with <b>pcre32_</b> instead of +<b>pcre_</b>. The prototypes are listed above. In addition, there is one extra +function, <b>pcre32_utf32_to_host_byte_order()</b>. This is a utility function +that converts a UTF-32 character string to host byte order if necessary. The +other 32-bit functions expect the strings they are passed to be in host byte +order. +</P> +<P> +The <i>input</i> and <i>output</i> arguments of +<b>pcre32_utf32_to_host_byte_order()</b> may point to the same address, that is, +conversion in place is supported. The output buffer must be at least as long as +the input. +</P> +<P> +The <i>length</i> argument specifies the number of 32-bit data units in the +input string; a negative value specifies a zero-terminated string. +</P> +<P> +If <i>byte_order</i> is NULL, it is assumed that the string starts off in host +byte order. This may be changed by byte-order marks (BOMs) anywhere in the +string (commonly as the first character). +</P> +<P> +If <i>byte_order</i> is not NULL, a non-zero value of the integer to which it +points means that the input starts off in host byte order, otherwise the +opposite order is assumed. Again, BOMs in the string can change this. The final +byte order is passed back at the end of processing. +</P> +<P> +If <i>keep_boms</i> is not zero, byte-order mark characters (0xfeff) are copied +into the output string. Otherwise they are discarded. +</P> +<P> +The result of the function is the number of 32-bit units placed into the output +buffer, including the zero terminator if the string was zero-terminated. +</P> +<br><a name="SEC12" href="#TOC1">SUBJECT STRING OFFSETS</a><br> +<P> +The lengths and starting offsets of subject strings must be specified in 32-bit +data units, and the offsets within subject strings that are returned by the +matching functions are in also 32-bit units rather than bytes. +</P> +<br><a name="SEC13" href="#TOC1">NAMED SUBPATTERNS</a><br> +<P> +The name-to-number translation table that is maintained for named subpatterns +uses 32-bit characters. The <b>pcre32_get_stringtable_entries()</b> function +returns the length of each entry in the table as the number of 32-bit data +units. +</P> +<br><a name="SEC14" href="#TOC1">OPTION NAMES</a><br> +<P> +There are two new general option names, PCRE_UTF32 and PCRE_NO_UTF32_CHECK, +which correspond to PCRE_UTF8 and PCRE_NO_UTF8_CHECK in the 8-bit library. In +fact, these new options define the same bits in the options word. There is a +discussion about the +<a href="pcreunicode.html#utf32strings">validity of UTF-32 strings</a> +in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. +</P> +<P> +For the <b>pcre32_config()</b> function there is an option PCRE_CONFIG_UTF32 +that returns 1 if UTF-32 support is configured, otherwise 0. If this option is +given to <b>pcre_config()</b> or <b>pcre16_config()</b>, or if the +PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF16 option is given to <b>pcre32_config()</b>, +the result is the PCRE_ERROR_BADOPTION error. +</P> +<br><a name="SEC15" href="#TOC1">CHARACTER CODES</a><br> +<P> +In 32-bit mode, when PCRE_UTF32 is not set, character values are treated in the +same way as in 8-bit, non UTF-8 mode, except, of course, that they can range +from 0 to 0x7fffffff instead of 0 to 0xff. Character types for characters less +than 0xff can therefore be influenced by the locale in the same way as before. +Characters greater than 0xff have only one case, and no "type" (such as letter +or digit). +</P> +<P> +In UTF-32 mode, the character code is Unicode, in the range 0 to 0x10ffff, with +the exception of values in the range 0xd800 to 0xdfff because those are +"surrogate" values that are ill-formed in UTF-32. +</P> +<P> +A UTF-32 string can indicate its endianness by special code knows as a +byte-order mark (BOM). The PCRE functions do not handle this, expecting strings +to be in host byte order. A utility function called +<b>pcre32_utf32_to_host_byte_order()</b> is provided to help with this (see +above). +</P> +<br><a name="SEC16" href="#TOC1">ERROR NAMES</a><br> +<P> +The error PCRE_ERROR_BADUTF32 corresponds to its 8-bit counterpart. +The error PCRE_ERROR_BADMODE is given when a compiled +pattern is passed to a function that processes patterns in the other +mode, for example, if a pattern compiled with <b>pcre_compile()</b> is passed to +<b>pcre32_exec()</b>. +</P> +<P> +There are new error codes whose names begin with PCRE_UTF32_ERR for invalid +UTF-32 strings, corresponding to the PCRE_UTF8_ERR codes for UTF-8 strings that +are described in the section entitled +<a href="pcreapi.html#badutf8reasons">"Reason codes for invalid UTF-8 strings"</a> +in the main +<a href="pcreapi.html"><b>pcreapi</b></a> +page. The UTF-32 errors are: +<pre> + PCRE_UTF32_ERR1 Surrogate character (range from 0xd800 to 0xdfff) + PCRE_UTF32_ERR2 Non-character + PCRE_UTF32_ERR3 Character > 0x10ffff +</PRE> +</P> +<br><a name="SEC17" href="#TOC1">ERROR TEXTS</a><br> +<P> +If there is an error while compiling a pattern, the error text that is passed +back by <b>pcre32_compile()</b> or <b>pcre32_compile2()</b> is still an 8-bit +character string, zero-terminated. +</P> +<br><a name="SEC18" href="#TOC1">CALLOUTS</a><br> +<P> +The <i>subject</i> and <i>mark</i> fields in the callout block that is passed to +a callout function point to 32-bit vectors. +</P> +<br><a name="SEC19" href="#TOC1">TESTING</a><br> +<P> +The <b>pcretest</b> program continues to operate with 8-bit input and output +files, but it can be used for testing the 32-bit library. If it is run with the +command line option <b>-32</b>, patterns and subject strings are converted from +8-bit to 32-bit before being passed to PCRE, and the 32-bit library functions +are used instead of the 8-bit ones. Returned 32-bit strings are converted to +8-bit for output. If both the 8-bit and the 16-bit libraries were not compiled, +<b>pcretest</b> defaults to 32-bit and the <b>-32</b> option is ignored. +</P> +<P> +When PCRE is being built, the <b>RunTest</b> script that is called by "make +check" uses the <b>pcretest</b> <b>-C</b> option to discover which of the 8-bit, +16-bit and 32-bit libraries has been built, and runs the tests appropriately. +</P> +<br><a name="SEC20" href="#TOC1">NOT SUPPORTED IN 32-BIT MODE</a><br> +<P> +Not all the features of the 8-bit library are available with the 32-bit +library. The C++ and POSIX wrapper functions support only the 8-bit library, +and the <b>pcregrep</b> program is at present 8-bit only. +</P> +<br><a name="SEC21" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC22" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 May 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_assign_jit_stack.html b/doc/html/pcre_assign_jit_stack.html new file mode 100644 index 0000000..b2eef70 --- /dev/null +++ b/doc/html/pcre_assign_jit_stack.html @@ -0,0 +1,76 @@ +<html> +<head> +<title>pcre_assign_jit_stack specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_assign_jit_stack man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b> +<b> pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> +<b>void pcre16_assign_jit_stack(pcre16_extra *<i>extra</i>,</b> +<b> pcre16_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> +<b>void pcre32_assign_jit_stack(pcre32_extra *<i>extra</i>,</b> +<b> pcre32_jit_callback <i>callback</i>, void *<i>data</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function provides control over the memory used as a stack at run-time by a +call to <b>pcre[16|32]_exec()</b> with a pattern that has been successfully +compiled with JIT optimization. The arguments are: +<pre> + extra the data pointer returned by <b>pcre[16|32]_study()</b> + callback a callback function + data a JIT stack or a value to be passed to the callback + function +</PRE> +</P> +<P> +If <i>callback</i> is NULL and <i>data</i> is NULL, an internal 32K block on +the machine stack is used. +</P> +<P> +If <i>callback</i> is NULL and <i>data</i> is not NULL, <i>data</i> must +be a valid JIT stack, the result of calling <b>pcre[16|32]_jit_stack_alloc()</b>. +</P> +<P> +If <i>callback</i> not NULL, it is called with <i>data</i> as an argument at +the start of matching, in order to set up a JIT stack. If the result is NULL, +the internal 32K stack is used; otherwise the return value must be a valid JIT +stack, the result of calling <b>pcre[16|32]_jit_stack_alloc()</b>. +</P> +<P> +You may safely assign the same JIT stack to multiple patterns, as long as they +are all matched in the same thread. In a multithread application, each thread +must use its own JIT stack. For more details, see the +<a href="pcrejit.html"><b>pcrejit</b></a> +page. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_compile.html b/doc/html/pcre_compile.html new file mode 100644 index 0000000..95b4bec --- /dev/null +++ b/doc/html/pcre_compile.html @@ -0,0 +1,111 @@ +<html> +<head> +<title>pcre_compile specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_compile man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre16 *pcre16_compile(PCRE_SPTR16 <i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre32 *pcre32_compile(PCRE_SPTR32 <i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function compiles a regular expression into an internal form. It is the +same as <b>pcre[16|32]_compile2()</b>, except for the absence of the +<i>errorcodeptr</i> argument. Its arguments are: +<pre> + <i>pattern</i> A zero-terminated string containing the + regular expression to be compiled + <i>options</i> Zero or more option bits + <i>errptr</i> Where to put an error message + <i>erroffset</i> Offset in pattern where error was found + <i>tableptr</i> Pointer to character tables, or NULL to + use the built-in default +</pre> +The option bits are: +<pre> + PCRE_ANCHORED Force pattern anchoring + PCRE_AUTO_CALLOUT Compile automatic callouts + PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF + PCRE_BSR_UNICODE \R matches all Unicode line endings + PCRE_CASELESS Do caseless matching + PCRE_DOLLAR_ENDONLY $ not to match newline at end + PCRE_DOTALL . matches anything including NL + PCRE_DUPNAMES Allow duplicate names for subpatterns + PCRE_EXTENDED Ignore white space and # comments + PCRE_EXTRA PCRE extra features + (not much use currently) + PCRE_FIRSTLINE Force matching to be before newline + PCRE_JAVASCRIPT_COMPAT JavaScript compatibility + PCRE_MULTILINE ^ and $ match newlines within data + PCRE_NEVER_UTF Lock out UTF, e.g. via (*UTF) + PCRE_NEWLINE_ANY Recognize any Unicode newline sequence + PCRE_NEWLINE_ANYCRLF Recognize CR, LF, and CRLF as newline + sequences + PCRE_NEWLINE_CR Set CR as the newline sequence + PCRE_NEWLINE_CRLF Set CRLF as the newline sequence + PCRE_NEWLINE_LF Set LF as the newline sequence + PCRE_NO_AUTO_CAPTURE Disable numbered capturing paren- + theses (named ones available) + PCRE_NO_AUTO_POSSESS Disable auto-possessification + PCRE_NO_START_OPTIMIZE Disable match-time start optimizations + PCRE_NO_UTF16_CHECK Do not check the pattern for UTF-16 + validity (only relevant if + PCRE_UTF16 is set) + PCRE_NO_UTF32_CHECK Do not check the pattern for UTF-32 + validity (only relevant if + PCRE_UTF32 is set) + PCRE_NO_UTF8_CHECK Do not check the pattern for UTF-8 + validity (only relevant if + PCRE_UTF8 is set) + PCRE_UCP Use Unicode properties for \d, \w, etc. + PCRE_UNGREEDY Invert greediness of quantifiers + PCRE_UTF16 Run in <b>pcre16_compile()</b> UTF-16 mode + PCRE_UTF32 Run in <b>pcre32_compile()</b> UTF-32 mode + PCRE_UTF8 Run in <b>pcre_compile()</b> UTF-8 mode +</pre> +PCRE must be built with UTF support in order to use PCRE_UTF8/16/32 and +PCRE_NO_UTF8/16/32_CHECK, and with UCP support if PCRE_UCP is used. +</P> +<P> +The yield of the function is a pointer to a private data structure that +contains the compiled pattern, or NULL if an error was detected. Note that +compiling regular expressions with one version of PCRE for use with a different +version is not guaranteed to work and may cause crashes. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_compile2.html b/doc/html/pcre_compile2.html new file mode 100644 index 0000000..9cd56a2 --- /dev/null +++ b/doc/html/pcre_compile2.html @@ -0,0 +1,115 @@ +<html> +<head> +<title>pcre_compile2 specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_compile2 man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>pcre *pcre_compile2(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre16 *pcre16_compile2(PCRE_SPTR16 <i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre32 *pcre32_compile2(PCRE_SPTR32 <i>pattern</i>, int <i>options</i>,</b> +<b>" int *<i>errorcodeptr</i>,£</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function compiles a regular expression into an internal form. It is the +same as <b>pcre[16|32]_compile()</b>, except for the addition of the +<i>errorcodeptr</i> argument. The arguments are: +<pre> + <i>pattern</i> A zero-terminated string containing the + regular expression to be compiled + <i>options</i> Zero or more option bits + <i>errorcodeptr</i> Where to put an error code + <i>errptr</i> Where to put an error message + <i>erroffset</i> Offset in pattern where error was found + <i>tableptr</i> Pointer to character tables, or NULL to + use the built-in default +</pre> +The option bits are: +<pre> + PCRE_ANCHORED Force pattern anchoring + PCRE_AUTO_CALLOUT Compile automatic callouts + PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF + PCRE_BSR_UNICODE \R matches all Unicode line endings + PCRE_CASELESS Do caseless matching + PCRE_DOLLAR_ENDONLY $ not to match newline at end + PCRE_DOTALL . matches anything including NL + PCRE_DUPNAMES Allow duplicate names for subpatterns + PCRE_EXTENDED Ignore white space and # comments + PCRE_EXTRA PCRE extra features + (not much use currently) + PCRE_FIRSTLINE Force matching to be before newline + PCRE_JAVASCRIPT_COMPAT JavaScript compatibility + PCRE_MULTILINE ^ and $ match newlines within data + PCRE_NEVER_UTF Lock out UTF, e.g. via (*UTF) + PCRE_NEWLINE_ANY Recognize any Unicode newline sequence + PCRE_NEWLINE_ANYCRLF Recognize CR, LF, and CRLF as newline + sequences + PCRE_NEWLINE_CR Set CR as the newline sequence + PCRE_NEWLINE_CRLF Set CRLF as the newline sequence + PCRE_NEWLINE_LF Set LF as the newline sequence + PCRE_NO_AUTO_CAPTURE Disable numbered capturing paren- + theses (named ones available) + PCRE_NO_AUTO_POSSESS Disable auto-possessification + PCRE_NO_START_OPTIMIZE Disable match-time start optimizations + PCRE_NO_UTF16_CHECK Do not check the pattern for UTF-16 + validity (only relevant if + PCRE_UTF16 is set) + PCRE_NO_UTF32_CHECK Do not check the pattern for UTF-32 + validity (only relevant if + PCRE_UTF32 is set) + PCRE_NO_UTF8_CHECK Do not check the pattern for UTF-8 + validity (only relevant if + PCRE_UTF8 is set) + PCRE_UCP Use Unicode properties for \d, \w, etc. + PCRE_UNGREEDY Invert greediness of quantifiers + PCRE_UTF16 Run <b>pcre16_compile()</b> in UTF-16 mode + PCRE_UTF32 Run <b>pcre32_compile()</b> in UTF-32 mode + PCRE_UTF8 Run <b>pcre_compile()</b> in UTF-8 mode +</pre> +PCRE must be built with UTF support in order to use PCRE_UTF8/16/32 and +PCRE_NO_UTF8/16/32_CHECK, and with UCP support if PCRE_UCP is used. +</P> +<P> +The yield of the function is a pointer to a private data structure that +contains the compiled pattern, or NULL if an error was detected. Note that +compiling regular expressions with one version of PCRE for use with a different +version is not guaranteed to work and may cause crashes. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_config.html b/doc/html/pcre_config.html new file mode 100644 index 0000000..bcdcdde --- /dev/null +++ b/doc/html/pcre_config.html @@ -0,0 +1,92 @@ +<html> +<head> +<title>pcre_config specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_config man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> +</P> +<P> +<b>int pcre16_config(int <i>what</i>, void *<i>where</i>);</b> +</P> +<P> +<b>int pcre32_config(int <i>what</i>, void *<i>where</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function makes it possible for a client program to find out which optional +features are available in the version of the PCRE library it is using. The +arguments are as follows: +<pre> + <i>what</i> A code specifying what information is required + <i>where</i> Points to where to put the data +</pre> +The <i>where</i> argument must point to an integer variable, except for +PCRE_CONFIG_MATCH_LIMIT and PCRE_CONFIG_MATCH_LIMIT_RECURSION, when it must +point to an unsigned long integer. The available codes are: +<pre> + PCRE_CONFIG_JIT Availability of just-in-time compiler + support (1=yes 0=no) + PCRE_CONFIG_JITTARGET String containing information about the + target architecture for the JIT compiler, + or NULL if there is no JIT support + PCRE_CONFIG_LINK_SIZE Internal link size: 2, 3, or 4 + PCRE_CONFIG_PARENS_LIMIT Parentheses nesting limit + PCRE_CONFIG_MATCH_LIMIT Internal resource limit + PCRE_CONFIG_MATCH_LIMIT_RECURSION + Internal recursion depth limit + PCRE_CONFIG_NEWLINE Value of the default newline sequence: + 13 (0x000d) for CR + 10 (0x000a) for LF + 3338 (0x0d0a) for CRLF + -2 for ANYCRLF + -1 for ANY + PCRE_CONFIG_BSR Indicates what \R matches by default: + 0 all Unicode line endings + 1 CR, LF, or CRLF only + PCRE_CONFIG_POSIX_MALLOC_THRESHOLD + Threshold of return slots, above which + <b>malloc()</b> is used by the POSIX API + PCRE_CONFIG_STACKRECURSE Recursion implementation (1=stack 0=heap) + PCRE_CONFIG_UTF16 Availability of UTF-16 support (1=yes + 0=no); option for <b>pcre16_config()</b> + PCRE_CONFIG_UTF32 Availability of UTF-32 support (1=yes + 0=no); option for <b>pcre32_config()</b> + PCRE_CONFIG_UTF8 Availability of UTF-8 support (1=yes 0=no); + option for <b>pcre_config()</b> + PCRE_CONFIG_UNICODE_PROPERTIES + Availability of Unicode property support + (1=yes 0=no) +</pre> +The function yields 0 on success or PCRE_ERROR_BADOPTION otherwise. That error +is also given if PCRE_CONFIG_UTF16 or PCRE_CONFIG_UTF32 is passed to +<b>pcre_config()</b>, if PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF32 is passed to +<b>pcre16_config()</b>, or if PCRE_CONFIG_UTF8 or PCRE_CONFIG_UTF16 is passed to +<b>pcre32_config()</b>. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_copy_named_substring.html b/doc/html/pcre_copy_named_substring.html new file mode 100644 index 0000000..77b4804 --- /dev/null +++ b/doc/html/pcre_copy_named_substring.html @@ -0,0 +1,65 @@ +<html> +<head> +<title>pcre_copy_named_substring specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_copy_named_substring man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> char *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre16_copy_named_substring(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR16 <i>stringname</i>,</b> +<b> PCRE_UCHAR16 *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre32_copy_named_substring(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR32 <i>stringname</i>,</b> +<b> PCRE_UCHAR32 *<i>buffer</i>, int <i>buffersize</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for extracting a captured substring, identified +by name, into a given buffer. The arguments are: +<pre> + <i>code</i> Pattern that was successfully matched + <i>subject</i> Subject that has been successfully matched + <i>ovector</i> Offset vector that <b>pcre[16|32]_exec()</b> used + <i>stringcount</i> Value returned by <b>pcre[16|32]_exec()</b> + <i>stringname</i> Name of the required substring + <i>buffer</i> Buffer to receive the string + <i>buffersize</i> Size of buffer +</pre> +The yield is the length of the substring, PCRE_ERROR_NOMEMORY if the buffer was +too small, or PCRE_ERROR_NOSUBSTRING if the string name is invalid. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_copy_substring.html b/doc/html/pcre_copy_substring.html new file mode 100644 index 0000000..ecaebe8 --- /dev/null +++ b/doc/html/pcre_copy_substring.html @@ -0,0 +1,61 @@ +<html> +<head> +<title>pcre_copy_substring specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_copy_substring man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre16_copy_substring(PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, PCRE_UCHAR16 *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre32_copy_substring(PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, PCRE_UCHAR32 *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for extracting a captured substring into a given +buffer. The arguments are: +<pre> + <i>subject</i> Subject that has been successfully matched + <i>ovector</i> Offset vector that <b>pcre[16|32]_exec()</b> used + <i>stringcount</i> Value returned by <b>pcre[16|32]_exec()</b> + <i>stringnumber</i> Number of the required substring + <i>buffer</i> Buffer to receive the string + <i>buffersize</i> Size of buffer +</pre> +The yield is the length of the string, PCRE_ERROR_NOMEMORY if the buffer was +too small, or PCRE_ERROR_NOSUBSTRING if the string number is invalid. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_dfa_exec.html b/doc/html/pcre_dfa_exec.html new file mode 100644 index 0000000..5fff6a7 --- /dev/null +++ b/doc/html/pcre_dfa_exec.html @@ -0,0 +1,129 @@ +<html> +<head> +<title>pcre_dfa_exec specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_dfa_exec man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_dfa_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +<br> +<br> +<b>int pcre16_dfa_exec(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +<br> +<br> +<b>int pcre32_dfa_exec(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function matches a compiled regular expression against a given subject +string, using an alternative matching algorithm that scans the subject string +just once (<i>not</i> Perl-compatible). Note that the main, Perl-compatible, +matching function is <b>pcre[16|32]_exec()</b>. The arguments for this function +are: +<pre> + <i>code</i> Points to the compiled pattern + <i>extra</i> Points to an associated <b>pcre[16|32]_extra</b> structure, + or is NULL + <i>subject</i> Points to the subject string + <i>length</i> Length of the subject string + <i>startoffset</i> Offset in the subject at which to start matching + <i>options</i> Option bits + <i>ovector</i> Points to a vector of ints for result offsets + <i>ovecsize</i> Number of elements in the vector + <i>workspace</i> Points to a vector of ints used as working space + <i>wscount</i> Number of elements in the vector +</pre> +The units for <i>length</i> and <i>startoffset</i> are bytes for +<b>pcre_exec()</b>, 16-bit data items for <b>pcre16_exec()</b>, and 32-bit items +for <b>pcre32_exec()</b>. The options are: +<pre> + PCRE_ANCHORED Match only at the first position + PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF + PCRE_BSR_UNICODE \R matches all Unicode line endings + PCRE_NEWLINE_ANY Recognize any Unicode newline sequence + PCRE_NEWLINE_ANYCRLF Recognize CR, LF, & CRLF as newline sequences + PCRE_NEWLINE_CR Recognize CR as the only newline sequence + PCRE_NEWLINE_CRLF Recognize CRLF as the only newline sequence + PCRE_NEWLINE_LF Recognize LF as the only newline sequence + PCRE_NOTBOL Subject is not the beginning of a line + PCRE_NOTEOL Subject is not the end of a line + PCRE_NOTEMPTY An empty string is not a valid match + PCRE_NOTEMPTY_ATSTART An empty string at the start of the subject + is not a valid match + PCRE_NO_START_OPTIMIZE Do not do "start-match" optimizations + PCRE_NO_UTF16_CHECK Do not check the subject for UTF-16 + validity (only relevant if PCRE_UTF16 + was set at compile time) + PCRE_NO_UTF32_CHECK Do not check the subject for UTF-32 + validity (only relevant if PCRE_UTF32 + was set at compile time) + PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8 + validity (only relevant if PCRE_UTF8 + was set at compile time) + PCRE_PARTIAL ) Return PCRE_ERROR_PARTIAL for a partial + PCRE_PARTIAL_SOFT ) match if no full matches are found + PCRE_PARTIAL_HARD Return PCRE_ERROR_PARTIAL for a partial match + even if there is a full match as well + PCRE_DFA_SHORTEST Return only the shortest match + PCRE_DFA_RESTART Restart after a partial match +</pre> +There are restrictions on what may appear in a pattern when using this matching +function. Details are given in the +<a href="pcrematching.html"><b>pcrematching</b></a> +documentation. For details of partial matching, see the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +page. +</P> +<P> +A <b>pcre[16|32]_extra</b> structure contains the following fields: +<pre> + <i>flags</i> Bits indicating which fields are set + <i>study_data</i> Opaque data from <b>pcre[16|32]_study()</b> + <i>match_limit</i> Limit on internal resource use + <i>match_limit_recursion</i> Limit on internal recursion depth + <i>callout_data</i> Opaque data passed back to callouts + <i>tables</i> Points to character tables or is NULL + <i>mark</i> For passing back a *MARK pointer + <i>executable_jit</i> Opaque data from JIT compilation +</pre> +The flag bits are PCRE_EXTRA_STUDY_DATA, PCRE_EXTRA_MATCH_LIMIT, +PCRE_EXTRA_MATCH_LIMIT_RECURSION, PCRE_EXTRA_CALLOUT_DATA, +PCRE_EXTRA_TABLES, PCRE_EXTRA_MARK and PCRE_EXTRA_EXECUTABLE_JIT. For this +matching function, the <i>match_limit</i> and <i>match_limit_recursion</i> fields +are not used, and must not be set. The PCRE_EXTRA_EXECUTABLE_JIT flag and +the corresponding variable are ignored. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_exec.html b/doc/html/pcre_exec.html new file mode 100644 index 0000000..18e1a13 --- /dev/null +++ b/doc/html/pcre_exec.html @@ -0,0 +1,111 @@ +<html> +<head> +<title>pcre_exec specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_exec man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +<br> +<br> +<b>int pcre16_exec(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +<br> +<br> +<b>int pcre32_exec(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function matches a compiled regular expression against a given subject +string, using a matching algorithm that is similar to Perl's. It returns +offsets to captured substrings. Its arguments are: +<pre> + <i>code</i> Points to the compiled pattern + <i>extra</i> Points to an associated <b>pcre[16|32]_extra</b> structure, + or is NULL + <i>subject</i> Points to the subject string + <i>length</i> Length of the subject string + <i>startoffset</i> Offset in the subject at which to start matching + <i>options</i> Option bits + <i>ovector</i> Points to a vector of ints for result offsets + <i>ovecsize</i> Number of elements in the vector (a multiple of 3) +</pre> +The units for <i>length</i> and <i>startoffset</i> are bytes for +<b>pcre_exec()</b>, 16-bit data items for <b>pcre16_exec()</b>, and 32-bit items +for <b>pcre32_exec()</b>. The options are: +<pre> + PCRE_ANCHORED Match only at the first position + PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF + PCRE_BSR_UNICODE \R matches all Unicode line endings + PCRE_NEWLINE_ANY Recognize any Unicode newline sequence + PCRE_NEWLINE_ANYCRLF Recognize CR, LF, & CRLF as newline sequences + PCRE_NEWLINE_CR Recognize CR as the only newline sequence + PCRE_NEWLINE_CRLF Recognize CRLF as the only newline sequence + PCRE_NEWLINE_LF Recognize LF as the only newline sequence + PCRE_NOTBOL Subject string is not the beginning of a line + PCRE_NOTEOL Subject string is not the end of a line + PCRE_NOTEMPTY An empty string is not a valid match + PCRE_NOTEMPTY_ATSTART An empty string at the start of the subject + is not a valid match + PCRE_NO_START_OPTIMIZE Do not do "start-match" optimizations + PCRE_NO_UTF16_CHECK Do not check the subject for UTF-16 + validity (only relevant if PCRE_UTF16 + was set at compile time) + PCRE_NO_UTF32_CHECK Do not check the subject for UTF-32 + validity (only relevant if PCRE_UTF32 + was set at compile time) + PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8 + validity (only relevant if PCRE_UTF8 + was set at compile time) + PCRE_PARTIAL ) Return PCRE_ERROR_PARTIAL for a partial + PCRE_PARTIAL_SOFT ) match if no full matches are found + PCRE_PARTIAL_HARD Return PCRE_ERROR_PARTIAL for a partial match + if that is found before a full match +</pre> +For details of partial matching, see the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +page. A <b>pcre_extra</b> structure contains the following fields: +<pre> + <i>flags</i> Bits indicating which fields are set + <i>study_data</i> Opaque data from <b>pcre[16|32]_study()</b> + <i>match_limit</i> Limit on internal resource use + <i>match_limit_recursion</i> Limit on internal recursion depth + <i>callout_data</i> Opaque data passed back to callouts + <i>tables</i> Points to character tables or is NULL + <i>mark</i> For passing back a *MARK pointer + <i>executable_jit</i> Opaque data from JIT compilation +</pre> +The flag bits are PCRE_EXTRA_STUDY_DATA, PCRE_EXTRA_MATCH_LIMIT, +PCRE_EXTRA_MATCH_LIMIT_RECURSION, PCRE_EXTRA_CALLOUT_DATA, +PCRE_EXTRA_TABLES, PCRE_EXTRA_MARK and PCRE_EXTRA_EXECUTABLE_JIT. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_free_study.html b/doc/html/pcre_free_study.html new file mode 100644 index 0000000..7f9e10e --- /dev/null +++ b/doc/html/pcre_free_study.html @@ -0,0 +1,46 @@ +<html> +<head> +<title>pcre_free_study specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_free_study man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>void pcre_free_study(pcre_extra *<i>extra</i>);</b> +</P> +<P> +<b>void pcre16_free_study(pcre16_extra *<i>extra</i>);</b> +</P> +<P> +<b>void pcre32_free_study(pcre32_extra *<i>extra</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function is used to free the memory used for the data generated by a call +to <b>pcre[16|32]_study()</b> when it is no longer needed. The argument must be the +result of such a call. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_free_substring.html b/doc/html/pcre_free_substring.html new file mode 100644 index 0000000..1fe6610 --- /dev/null +++ b/doc/html/pcre_free_substring.html @@ -0,0 +1,46 @@ +<html> +<head> +<title>pcre_free_substring specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_free_substring man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>void pcre_free_substring(const char *<i>stringptr</i>);</b> +</P> +<P> +<b>void pcre16_free_substring(PCRE_SPTR16 <i>stringptr</i>);</b> +</P> +<P> +<b>void pcre32_free_substring(PCRE_SPTR32 <i>stringptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for freeing the store obtained by a previous +call to <b>pcre[16|32]_get_substring()</b> or <b>pcre[16|32]_get_named_substring()</b>. +Its only argument is a pointer to the string. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_free_substring_list.html b/doc/html/pcre_free_substring_list.html new file mode 100644 index 0000000..c086178 --- /dev/null +++ b/doc/html/pcre_free_substring_list.html @@ -0,0 +1,46 @@ +<html> +<head> +<title>pcre_free_substring_list specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_free_substring_list man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b> +</P> +<P> +<b>void pcre16_free_substring_list(PCRE_SPTR16 *<i>stringptr</i>);</b> +</P> +<P> +<b>void pcre32_free_substring_list(PCRE_SPTR32 *<i>stringptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for freeing the store obtained by a previous +call to <b>pcre[16|32]_get_substring_list()</b>. Its only argument is a pointer to +the list of string pointers. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_fullinfo.html b/doc/html/pcre_fullinfo.html new file mode 100644 index 0000000..b88fc11 --- /dev/null +++ b/doc/html/pcre_fullinfo.html @@ -0,0 +1,108 @@ +<html> +<head> +<title>pcre_fullinfo specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_fullinfo man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>int pcre16_fullinfo(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>int pcre32_fullinfo(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function returns information about a compiled pattern. Its arguments are: +<pre> + <i>code</i> Compiled regular expression + <i>extra</i> Result of <b>pcre[16|32]_study()</b> or NULL + <i>what</i> What information is required + <i>where</i> Where to put the information +</pre> +The following information is available: +<pre> + PCRE_INFO_BACKREFMAX Number of highest back reference + PCRE_INFO_CAPTURECOUNT Number of capturing subpatterns + PCRE_INFO_DEFAULT_TABLES Pointer to default tables + PCRE_INFO_FIRSTBYTE Fixed first data unit for a match, or + -1 for start of string + or after newline, or + -2 otherwise + PCRE_INFO_FIRSTTABLE Table of first data units (after studying) + PCRE_INFO_HASCRORLF Return 1 if explicit CR or LF matches exist + PCRE_INFO_JCHANGED Return 1 if (?J) or (?-J) was used + PCRE_INFO_JIT Return 1 after successful JIT compilation + PCRE_INFO_JITSIZE Size of JIT compiled code + PCRE_INFO_LASTLITERAL Literal last data unit required + PCRE_INFO_MINLENGTH Lower bound length of matching strings + PCRE_INFO_NAMECOUNT Number of named subpatterns + PCRE_INFO_NAMEENTRYSIZE Size of name table entry + PCRE_INFO_NAMETABLE Pointer to name table + PCRE_INFO_OKPARTIAL Return 1 if partial matching can be tried + (always returns 1 after release 8.00) + PCRE_INFO_OPTIONS Option bits used for compilation + PCRE_INFO_SIZE Size of compiled pattern + PCRE_INFO_STUDYSIZE Size of study data + PCRE_INFO_FIRSTCHARACTER Fixed first data unit for a match + PCRE_INFO_FIRSTCHARACTERFLAGS Returns + 1 if there is a first data character set, which can + then be retrieved using PCRE_INFO_FIRSTCHARACTER, + 2 if the first character is at the start of the data + string or after a newline, and + 0 otherwise + PCRE_INFO_REQUIREDCHAR Literal last data unit required + PCRE_INFO_REQUIREDCHARFLAGS Returns 1 if the last data character is set (which can then + be retrieved using PCRE_INFO_REQUIREDCHAR); 0 otherwise +</pre> +The <i>where</i> argument must point to an integer variable, except for the +following <i>what</i> values: +<pre> + PCRE_INFO_DEFAULT_TABLES const unsigned char * + PCRE_INFO_FIRSTTABLE const unsigned char * + PCRE_INFO_NAMETABLE PCRE_SPTR16 (16-bit library) + PCRE_INFO_NAMETABLE PCRE_SPTR32 (32-bit library) + PCRE_INFO_NAMETABLE const unsigned char * (8-bit library) + PCRE_INFO_OPTIONS unsigned long int + PCRE_INFO_SIZE size_t + PCRE_INFO_FIRSTCHARACTER uint32_t + PCRE_INFO_REQUIREDCHAR uint32_t +</pre> +The yield of the function is zero on success or: +<pre> + PCRE_ERROR_NULL the argument <i>code</i> was NULL + the argument <i>where</i> was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid +</PRE> +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_get_named_substring.html b/doc/html/pcre_get_named_substring.html new file mode 100644 index 0000000..72924d9 --- /dev/null +++ b/doc/html/pcre_get_named_substring.html @@ -0,0 +1,68 @@ +<html> +<head> +<title>pcre_get_named_substring specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_get_named_substring man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre16_get_named_substring(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR16 <i>stringname</i>,</b> +<b> PCRE_SPTR16 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre32_get_named_substring(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, PCRE_SPTR32 <i>stringname</i>,</b> +<b> PCRE_SPTR32 *<i>stringptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for extracting a captured substring by name. The +arguments are: +<pre> + <i>code</i> Compiled pattern + <i>subject</i> Subject that has been successfully matched + <i>ovector</i> Offset vector that <b>pcre[16|32]_exec()</b> used + <i>stringcount</i> Value returned by <b>pcre[16|32]_exec()</b> + <i>stringname</i> Name of the required substring + <i>stringptr</i> Where to put the string pointer +</pre> +The memory in which the substring is placed is obtained by calling +<b>pcre[16|32]_malloc()</b>. The convenience function +<b>pcre[16|32]_free_substring()</b> can be used to free it when it is no longer +needed. The yield of the function is the length of the extracted substring, +PCRE_ERROR_NOMEMORY if sufficient memory could not be obtained, or +PCRE_ERROR_NOSUBSTRING if the string name is invalid. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_get_stringnumber.html b/doc/html/pcre_get_stringnumber.html new file mode 100644 index 0000000..7324d78 --- /dev/null +++ b/doc/html/pcre_get_stringnumber.html @@ -0,0 +1,57 @@ +<html> +<head> +<title>pcre_get_stringnumber specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_get_stringnumber man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>);</b> +<br> +<br> +<b>int pcre16_get_stringnumber(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>name</i>);</b> +<br> +<br> +<b>int pcre32_get_stringnumber(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>name</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This convenience function finds the number of a named substring capturing +parenthesis in a compiled pattern. Its arguments are: +<pre> + <i>code</i> Compiled regular expression + <i>name</i> Name whose number is required +</pre> +The yield of the function is the number of the parenthesis if the name is +found, or PCRE_ERROR_NOSUBSTRING otherwise. When duplicate names are allowed +(PCRE_DUPNAMES is set), it is not defined which of the numbers is returned by +<b>pcre[16|32]_get_stringnumber()</b>. You can obtain the complete list by calling +<b>pcre[16|32]_get_stringtable_entries()</b>. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_get_stringtable_entries.html b/doc/html/pcre_get_stringtable_entries.html new file mode 100644 index 0000000..7990679 --- /dev/null +++ b/doc/html/pcre_get_stringtable_entries.html @@ -0,0 +1,60 @@ +<html> +<head> +<title>pcre_get_stringtable_entries specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_get_stringtable_entries man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> +<br> +<br> +<b>int pcre16_get_stringtable_entries(const pcre16 *<i>code</i>,</b> +<b> PCRE_SPTR16 <i>name</i>, PCRE_UCHAR16 **<i>first</i>, PCRE_UCHAR16 **<i>last</i>);</b> +<br> +<br> +<b>int pcre32_get_stringtable_entries(const pcre32 *<i>code</i>,</b> +<b> PCRE_SPTR32 <i>name</i>, PCRE_UCHAR32 **<i>first</i>, PCRE_UCHAR32 **<i>last</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This convenience function finds, for a compiled pattern, the first and last +entries for a given name in the table that translates capturing parenthesis +names into numbers. When names are required to be unique (PCRE_DUPNAMES is +<i>not</i> set), it is usually easier to use <b>pcre[16|32]_get_stringnumber()</b> +instead. +<pre> + <i>code</i> Compiled regular expression + <i>name</i> Name whose entries required + <i>first</i> Where to return a pointer to the first entry + <i>last</i> Where to return a pointer to the last entry +</pre> +The yield of the function is the length of each entry, or +PCRE_ERROR_NOSUBSTRING if none are found. +</P> +<P> +There is a complete description of the PCRE native API, including the format of +the table entries, in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page, and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_get_substring.html b/doc/html/pcre_get_substring.html new file mode 100644 index 0000000..1a8e4f5 --- /dev/null +++ b/doc/html/pcre_get_substring.html @@ -0,0 +1,64 @@ +<html> +<head> +<title>pcre_get_substring specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_get_substring man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre16_get_substring(PCRE_SPTR16 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> PCRE_SPTR16 *<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre32_get_substring(PCRE_SPTR32 <i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> PCRE_SPTR32 *<i>stringptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for extracting a captured substring. The +arguments are: +<pre> + <i>subject</i> Subject that has been successfully matched + <i>ovector</i> Offset vector that <b>pcre[16|32]_exec()</b> used + <i>stringcount</i> Value returned by <b>pcre[16|32]_exec()</b> + <i>stringnumber</i> Number of the required substring + <i>stringptr</i> Where to put the string pointer +</pre> +The memory in which the substring is placed is obtained by calling +<b>pcre[16|32]_malloc()</b>. The convenience function +<b>pcre[16|32]_free_substring()</b> can be used to free it when it is no longer +needed. The yield of the function is the length of the substring, +PCRE_ERROR_NOMEMORY if sufficient memory could not be obtained, or +PCRE_ERROR_NOSUBSTRING if the string number is invalid. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_get_substring_list.html b/doc/html/pcre_get_substring_list.html new file mode 100644 index 0000000..7e8c6bc --- /dev/null +++ b/doc/html/pcre_get_substring_list.html @@ -0,0 +1,61 @@ +<html> +<head> +<title>pcre_get_substring_list specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_get_substring_list man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> +<br> +<br> +<b>int pcre16_get_substring_list(PCRE_SPTR16 <i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, PCRE_SPTR16 **<i>listptr</i>);</b> +<br> +<br> +<b>int pcre32_get_substring_list(PCRE_SPTR32 <i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, PCRE_SPTR32 **<i>listptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This is a convenience function for extracting a list of all the captured +substrings. The arguments are: +<pre> + <i>subject</i> Subject that has been successfully matched + <i>ovector</i> Offset vector that <b>pcre[16|32]_exec</b> used + <i>stringcount</i> Value returned by <b>pcre[16|32]_exec</b> + <i>listptr</i> Where to put a pointer to the list +</pre> +The memory in which the substrings and the list are placed is obtained by +calling <b>pcre[16|32]_malloc()</b>. The convenience function +<b>pcre[16|32]_free_substring_list()</b> can be used to free it when it is no +longer needed. A pointer to a list of pointers is put in the variable whose +address is in <i>listptr</i>. The list is terminated by a NULL pointer. The +yield of the function is zero on success or PCRE_ERROR_NOMEMORY if sufficient +memory could not be obtained. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_jit_exec.html b/doc/html/pcre_jit_exec.html new file mode 100644 index 0000000..4ebb0cb --- /dev/null +++ b/doc/html/pcre_jit_exec.html @@ -0,0 +1,108 @@ +<html> +<head> +<title>pcre_jit_exec specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_jit_exec man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_jit_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> pcre_jit_stack *<i>jstack</i>);</b> +<br> +<br> +<b>int pcre16_jit_exec(const pcre16 *<i>code</i>, const pcre16_extra *<i>extra</i>,</b> +<b> PCRE_SPTR16 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> pcre_jit_stack *<i>jstack</i>);</b> +<br> +<br> +<b>int pcre32_jit_exec(const pcre32 *<i>code</i>, const pcre32_extra *<i>extra</i>,</b> +<b> PCRE_SPTR32 <i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> pcre_jit_stack *<i>jstack</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function matches a compiled regular expression that has been successfully +studied with one of the JIT options against a given subject string, using a +matching algorithm that is similar to Perl's. It is a "fast path" interface to +JIT, and it bypasses some of the sanity checks that <b>pcre_exec()</b> applies. +It returns offsets to captured substrings. Its arguments are: +<pre> + <i>code</i> Points to the compiled pattern + <i>extra</i> Points to an associated <b>pcre[16|32]_extra</b> structure, + or is NULL + <i>subject</i> Points to the subject string + <i>length</i> Length of the subject string, in bytes + <i>startoffset</i> Offset in bytes in the subject at which to + start matching + <i>options</i> Option bits + <i>ovector</i> Points to a vector of ints for result offsets + <i>ovecsize</i> Number of elements in the vector (a multiple of 3) + <i>jstack</i> Pointer to a JIT stack +</pre> +The allowed options are: +<pre> + PCRE_NOTBOL Subject string is not the beginning of a line + PCRE_NOTEOL Subject string is not the end of a line + PCRE_NOTEMPTY An empty string is not a valid match + PCRE_NOTEMPTY_ATSTART An empty string at the start of the subject + is not a valid match + PCRE_NO_UTF16_CHECK Do not check the subject for UTF-16 + validity (only relevant if PCRE_UTF16 + was set at compile time) + PCRE_NO_UTF32_CHECK Do not check the subject for UTF-32 + validity (only relevant if PCRE_UTF32 + was set at compile time) + PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8 + validity (only relevant if PCRE_UTF8 + was set at compile time) + PCRE_PARTIAL ) Return PCRE_ERROR_PARTIAL for a partial + PCRE_PARTIAL_SOFT ) match if no full matches are found + PCRE_PARTIAL_HARD Return PCRE_ERROR_PARTIAL for a partial match + if that is found before a full match +</pre> +However, the PCRE_NO_UTF[8|16|32]_CHECK options have no effect, as this check +is never applied. For details of partial matching, see the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +page. A <b>pcre_extra</b> structure contains the following fields: +<pre> + <i>flags</i> Bits indicating which fields are set + <i>study_data</i> Opaque data from <b>pcre[16|32]_study()</b> + <i>match_limit</i> Limit on internal resource use + <i>match_limit_recursion</i> Limit on internal recursion depth + <i>callout_data</i> Opaque data passed back to callouts + <i>tables</i> Points to character tables or is NULL + <i>mark</i> For passing back a *MARK pointer + <i>executable_jit</i> Opaque data from JIT compilation +</pre> +The flag bits are PCRE_EXTRA_STUDY_DATA, PCRE_EXTRA_MATCH_LIMIT, +PCRE_EXTRA_MATCH_LIMIT_RECURSION, PCRE_EXTRA_CALLOUT_DATA, +PCRE_EXTRA_TABLES, PCRE_EXTRA_MARK and PCRE_EXTRA_EXECUTABLE_JIT. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the JIT API in the +<a href="pcrejit.html"><b>pcrejit</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_jit_stack_alloc.html b/doc/html/pcre_jit_stack_alloc.html new file mode 100644 index 0000000..23ba450 --- /dev/null +++ b/doc/html/pcre_jit_stack_alloc.html @@ -0,0 +1,55 @@ +<html> +<head> +<title>pcre_jit_stack_alloc specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_jit_stack_alloc man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>,</b> +<b> int <i>maxsize</i>);</b> +<br> +<br> +<b>pcre16_jit_stack *pcre16_jit_stack_alloc(int <i>startsize</i>,</b> +<b> int <i>maxsize</i>);</b> +<br> +<br> +<b>pcre32_jit_stack *pcre32_jit_stack_alloc(int <i>startsize</i>,</b> +<b> int <i>maxsize</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function is used to create a stack for use by the code compiled by the JIT +optimization of <b>pcre[16|32]_study()</b>. The arguments are a starting size for +the stack, and a maximum size to which it is allowed to grow. The result can be +passed to the JIT run-time code by <b>pcre[16|32]_assign_jit_stack()</b>, or that +function can set up a callback for obtaining a stack. A maximum stack size of +512K to 1M should be more than enough for any pattern. For more details, see +the +<a href="pcrejit.html"><b>pcrejit</b></a> +page. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_jit_stack_free.html b/doc/html/pcre_jit_stack_free.html new file mode 100644 index 0000000..8bd06e4 --- /dev/null +++ b/doc/html/pcre_jit_stack_free.html @@ -0,0 +1,48 @@ +<html> +<head> +<title>pcre_jit_stack_free specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_jit_stack_free man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b> +</P> +<P> +<b>void pcre16_jit_stack_free(pcre16_jit_stack *<i>stack</i>);</b> +</P> +<P> +<b>void pcre32_jit_stack_free(pcre32_jit_stack *<i>stack</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function is used to free a JIT stack that was created by +<b>pcre[16|32]_jit_stack_alloc()</b> when it is no longer needed. For more details, +see the +<a href="pcrejit.html"><b>pcrejit</b></a> +page. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_maketables.html b/doc/html/pcre_maketables.html new file mode 100644 index 0000000..3a7b5eb --- /dev/null +++ b/doc/html/pcre_maketables.html @@ -0,0 +1,48 @@ +<html> +<head> +<title>pcre_maketables specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_maketables man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>const unsigned char *pcre_maketables(void);</b> +</P> +<P> +<b>const unsigned char *pcre16_maketables(void);</b> +</P> +<P> +<b>const unsigned char *pcre32_maketables(void);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function builds a set of character tables for character values less than +256. These can be passed to <b>pcre[16|32]_compile()</b> to override PCRE's +internal, built-in tables (which were made by <b>pcre[16|32]_maketables()</b> when +PCRE was compiled). You might want to do this if you are using a non-standard +locale. The function yields a pointer to the tables. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_pattern_to_host_byte_order.html b/doc/html/pcre_pattern_to_host_byte_order.html new file mode 100644 index 0000000..1b1c803 --- /dev/null +++ b/doc/html/pcre_pattern_to_host_byte_order.html @@ -0,0 +1,58 @@ +<html> +<head> +<title>pcre_pattern_to_host_byte_order specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_pattern_to_host_byte_order man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_pattern_to_host_byte_order(pcre *<i>code</i>,</b> +<b> pcre_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +<br> +<br> +<b>int pcre16_pattern_to_host_byte_order(pcre16 *<i>code</i>,</b> +<b> pcre16_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +<br> +<br> +<b>int pcre32_pattern_to_host_byte_order(pcre32 *<i>code</i>,</b> +<b> pcre32_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function ensures that the bytes in 2-byte and 4-byte values in a compiled +pattern are in the correct order for the current host. It is useful when a +pattern that has been compiled on one host is transferred to another that might +have different endianness. The arguments are: +<pre> + <i>code</i> A compiled regular expression + <i>extra</i> Points to an associated <b>pcre[16|32]_extra</b> structure, + or is NULL + <i>tables</i> Pointer to character tables, or NULL to + set the built-in default +</pre> +The result is 0 for success, a negative PCRE_ERROR_xxx value otherwise. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_refcount.html b/doc/html/pcre_refcount.html new file mode 100644 index 0000000..bfb92e6 --- /dev/null +++ b/doc/html/pcre_refcount.html @@ -0,0 +1,51 @@ +<html> +<head> +<title>pcre_refcount specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_refcount man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b> +</P> +<P> +<b>int pcre16_refcount(pcre16 *<i>code</i>, int <i>adjust</i>);</b> +</P> +<P> +<b>int pcre32_refcount(pcre32 *<i>code</i>, int <i>adjust</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function is used to maintain a reference count inside a data block that +contains a compiled pattern. Its arguments are: +<pre> + <i>code</i> Compiled regular expression + <i>adjust</i> Adjustment to reference value +</pre> +The yield of the function is the adjusted reference value, which is constrained +to lie between 0 and 65535. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_study.html b/doc/html/pcre_study.html new file mode 100644 index 0000000..af82f11 --- /dev/null +++ b/doc/html/pcre_study.html @@ -0,0 +1,68 @@ +<html> +<head> +<title>pcre_study specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_study man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +<br> +<br> +<b>pcre16_extra *pcre16_study(const pcre16 *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +<br> +<br> +<b>pcre32_extra *pcre32_study(const pcre32 *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function studies a compiled pattern, to see if additional information can +be extracted that might speed up matching. Its arguments are: +<pre> + <i>code</i> A compiled regular expression + <i>options</i> Options for <b>pcre[16|32]_study()</b> + <i>errptr</i> Where to put an error message +</pre> +If the function succeeds, it returns a value that can be passed to +<b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> via their <i>extra</i> +arguments. +</P> +<P> +If the function returns NULL, either it could not find any additional +information, or there was an error. You can tell the difference by looking at +the error value. It is NULL in first case. +</P> +<P> +The only option is PCRE_STUDY_JIT_COMPILE. It requests just-in-time compilation +if possible. If PCRE has been compiled without JIT support, this option is +ignored. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +page for further details. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_utf16_to_host_byte_order.html b/doc/html/pcre_utf16_to_host_byte_order.html new file mode 100644 index 0000000..18e7788 --- /dev/null +++ b/doc/html/pcre_utf16_to_host_byte_order.html @@ -0,0 +1,57 @@ +<html> +<head> +<title>pcre_utf16_to_host_byte_order specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_utf16_to_host_byte_order man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre16_utf16_to_host_byte_order(PCRE_UCHAR16 *<i>output</i>,</b> +<b> PCRE_SPTR16 <i>input</i>, int <i>length</i>, int *<i>host_byte_order</i>,</b> +<b> int <i>keep_boms</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function, which exists only in the 16-bit library, converts a UTF-16 +string to the correct order for the current host, taking account of any byte +order marks (BOMs) within the string. Its arguments are: +<pre> + <i>output</i> pointer to output buffer, may be the same as <i>input</i> + <i>input</i> pointer to input buffer + <i>length</i> number of 16-bit units in the input, or negative for + a zero-terminated string + <i>host_byte_order</i> a NULL value or a non-zero value pointed to means + start in host byte order + <i>keep_boms</i> if non-zero, BOMs are copied to the output string +</pre> +The result of the function is the number of 16-bit units placed into the output +buffer, including the zero terminator if the string was zero-terminated. +</P> +<P> +If <i>host_byte_order</i> is not NULL, it is set to indicate the byte order that +is current at the end of the string. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_utf32_to_host_byte_order.html b/doc/html/pcre_utf32_to_host_byte_order.html new file mode 100644 index 0000000..772ae40 --- /dev/null +++ b/doc/html/pcre_utf32_to_host_byte_order.html @@ -0,0 +1,57 @@ +<html> +<head> +<title>pcre_utf32_to_host_byte_order specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_utf32_to_host_byte_order man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int pcre32_utf32_to_host_byte_order(PCRE_UCHAR32 *<i>output</i>,</b> +<b> PCRE_SPTR32 <i>input</i>, int <i>length</i>, int *<i>host_byte_order</i>,</b> +<b> int <i>keep_boms</i>);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function, which exists only in the 32-bit library, converts a UTF-32 +string to the correct order for the current host, taking account of any byte +order marks (BOMs) within the string. Its arguments are: +<pre> + <i>output</i> pointer to output buffer, may be the same as <i>input</i> + <i>input</i> pointer to input buffer + <i>length</i> number of 32-bit units in the input, or negative for + a zero-terminated string + <i>host_byte_order</i> a NULL value or a non-zero value pointed to means + start in host byte order + <i>keep_boms</i> if non-zero, BOMs are copied to the output string +</pre> +The result of the function is the number of 32-bit units placed into the output +buffer, including the zero terminator if the string was zero-terminated. +</P> +<P> +If <i>host_byte_order</i> is not NULL, it is set to indicate the byte order that +is current at the end of the string. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcre_version.html b/doc/html/pcre_version.html new file mode 100644 index 0000000..d33e718 --- /dev/null +++ b/doc/html/pcre_version.html @@ -0,0 +1,46 @@ +<html> +<head> +<title>pcre_version specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcre_version man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SYNOPSIS +</b><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>const char *pcre_version(void);</b> +</P> +<P> +<b>const char *pcre16_version(void);</b> +</P> +<P> +<b>const char *pcre32_version(void);</b> +</P> +<br><b> +DESCRIPTION +</b><br> +<P> +This function (even in the 16-bit and 32-bit libraries) returns a +zero-terminated, 8-bit character string that gives the version number of the +PCRE library and the date of its release. +</P> +<P> +There is a complete description of the PCRE native API in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page and a description of the POSIX API in the +<a href="pcreposix.html"><b>pcreposix</b></a> +page. +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcreapi.html b/doc/html/pcreapi.html new file mode 100644 index 0000000..b401ecc --- /dev/null +++ b/doc/html/pcreapi.html @@ -0,0 +1,2922 @@ +<html> +<head> +<title>pcreapi specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcreapi man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE NATIVE API BASIC FUNCTIONS</a> +<li><a name="TOC2" href="#SEC2">PCRE NATIVE API STRING EXTRACTION FUNCTIONS</a> +<li><a name="TOC3" href="#SEC3">PCRE NATIVE API AUXILIARY FUNCTIONS</a> +<li><a name="TOC4" href="#SEC4">PCRE NATIVE API INDIRECTED FUNCTIONS</a> +<li><a name="TOC5" href="#SEC5">PCRE 8-BIT, 16-BIT, AND 32-BIT LIBRARIES</a> +<li><a name="TOC6" href="#SEC6">PCRE API OVERVIEW</a> +<li><a name="TOC7" href="#SEC7">NEWLINES</a> +<li><a name="TOC8" href="#SEC8">MULTITHREADING</a> +<li><a name="TOC9" href="#SEC9">SAVING PRECOMPILED PATTERNS FOR LATER USE</a> +<li><a name="TOC10" href="#SEC10">CHECKING BUILD-TIME OPTIONS</a> +<li><a name="TOC11" href="#SEC11">COMPILING A PATTERN</a> +<li><a name="TOC12" href="#SEC12">COMPILATION ERROR CODES</a> +<li><a name="TOC13" href="#SEC13">STUDYING A PATTERN</a> +<li><a name="TOC14" href="#SEC14">LOCALE SUPPORT</a> +<li><a name="TOC15" href="#SEC15">INFORMATION ABOUT A PATTERN</a> +<li><a name="TOC16" href="#SEC16">REFERENCE COUNTS</a> +<li><a name="TOC17" href="#SEC17">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a> +<li><a name="TOC18" href="#SEC18">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a> +<li><a name="TOC19" href="#SEC19">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a> +<li><a name="TOC20" href="#SEC20">DUPLICATE SUBPATTERN NAMES</a> +<li><a name="TOC21" href="#SEC21">FINDING ALL POSSIBLE MATCHES</a> +<li><a name="TOC22" href="#SEC22">OBTAINING AN ESTIMATE OF STACK USAGE</a> +<li><a name="TOC23" href="#SEC23">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a> +<li><a name="TOC24" href="#SEC24">SEE ALSO</a> +<li><a name="TOC25" href="#SEC25">AUTHOR</a> +<li><a name="TOC26" href="#SEC26">REVISION</a> +</ul> +<P> +<b>#include <pcre.h></b> +</P> +<br><a name="SEC1" href="#TOC1">PCRE NATIVE API BASIC FUNCTIONS</a><br> +<P> +<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre *pcre_compile2(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +<br> +<br> +<b>void pcre_free_study(pcre_extra *<i>extra</i>);</b> +<br> +<br> +<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +<br> +<br> +<b>int pcre_dfa_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +</P> +<br><a name="SEC2" href="#TOC1">PCRE NATIVE API STRING EXTRACTION FUNCTIONS</a><br> +<P> +<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> char *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>);</b> +<br> +<br> +<b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> +<br> +<br> +<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> +<br> +<br> +<b>void pcre_free_substring(const char *<i>stringptr</i>);</b> +<br> +<br> +<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b> +</P> +<br><a name="SEC3" href="#TOC1">PCRE NATIVE API AUXILIARY FUNCTIONS</a><br> +<P> +<b>int pcre_jit_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> pcre_jit_stack *<i>jstack</i>);</b> +<br> +<br> +<b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b> +<br> +<br> +<b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b> +<br> +<br> +<b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b> +<b> pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> +<b>const unsigned char *pcre_maketables(void);</b> +<br> +<br> +<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b> +<br> +<br> +<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> +<br> +<br> +<b>const char *pcre_version(void);</b> +<br> +<br> +<b>int pcre_pattern_to_host_byte_order(pcre *<i>code</i>,</b> +<b> pcre_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +</P> +<br><a name="SEC4" href="#TOC1">PCRE NATIVE API INDIRECTED FUNCTIONS</a><br> +<P> +<b>void *(*pcre_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre_free)(void *);</b> +<br> +<br> +<b>void *(*pcre_stack_malloc)(size_t);</b> +<br> +<br> +<b>void (*pcre_stack_free)(void *);</b> +<br> +<br> +<b>int (*pcre_callout)(pcre_callout_block *);</b> +<br> +<br> +<b>int (*pcre_stack_guard)(void);</b> +</P> +<br><a name="SEC5" href="#TOC1">PCRE 8-BIT, 16-BIT, AND 32-BIT LIBRARIES</a><br> +<P> +As well as support for 8-bit character strings, PCRE also supports 16-bit +strings (from release 8.30) and 32-bit strings (from release 8.32), by means of +two additional libraries. They can be built as well as, or instead of, the +8-bit library. To avoid too much complication, this document describes the +8-bit versions of the functions, with only occasional references to the 16-bit +and 32-bit libraries. +</P> +<P> +The 16-bit and 32-bit functions operate in the same way as their 8-bit +counterparts; they just use different data types for their arguments and +results, and their names start with <b>pcre16_</b> or <b>pcre32_</b> instead of +<b>pcre_</b>. For every option that has UTF8 in its name (for example, +PCRE_UTF8), there are corresponding 16-bit and 32-bit names with UTF8 replaced +by UTF16 or UTF32, respectively. This facility is in fact just cosmetic; the +16-bit and 32-bit option names define the same bit values. +</P> +<P> +References to bytes and UTF-8 in this document should be read as references to +16-bit data units and UTF-16 when using the 16-bit library, or 32-bit data +units and UTF-32 when using the 32-bit library, unless specified otherwise. +More details of the specific differences for the 16-bit and 32-bit libraries +are given in the +<a href="pcre16.html"><b>pcre16</b></a> +and +<a href="pcre32.html"><b>pcre32</b></a> +pages. +</P> +<br><a name="SEC6" href="#TOC1">PCRE API OVERVIEW</a><br> +<P> +PCRE has its own native API, which is described in this document. There are +also some wrapper functions (for the 8-bit library only) that correspond to the +POSIX regular expression API, but they do not give access to all the +functionality. They are described in the +<a href="pcreposix.html"><b>pcreposix</b></a> +documentation. Both of these APIs define a set of C function calls. A C++ +wrapper (again for the 8-bit library only) is also distributed with PCRE. It is +documented in the +<a href="pcrecpp.html"><b>pcrecpp</b></a> +page. +</P> +<P> +The native API C function prototypes are defined in the header file +<b>pcre.h</b>, and on Unix-like systems the (8-bit) library itself is called +<b>libpcre</b>. It can normally be accessed by adding <b>-lpcre</b> to the +command for linking an application that uses PCRE. The header file defines the +macros PCRE_MAJOR and PCRE_MINOR to contain the major and minor release numbers +for the library. Applications can use these to include support for different +releases of PCRE. +</P> +<P> +In a Windows environment, if you want to statically link an application program +against a non-dll <b>pcre.a</b> file, you must define PCRE_STATIC before +including <b>pcre.h</b> or <b>pcrecpp.h</b>, because otherwise the +<b>pcre_malloc()</b> and <b>pcre_free()</b> exported functions will be declared +<b>__declspec(dllimport)</b>, with unwanted results. +</P> +<P> +The functions <b>pcre_compile()</b>, <b>pcre_compile2()</b>, <b>pcre_study()</b>, +and <b>pcre_exec()</b> are used for compiling and matching regular expressions +in a Perl-compatible manner. A sample program that demonstrates the simplest +way of using them is provided in the file called <i>pcredemo.c</i> in the PCRE +source distribution. A listing of this program is given in the +<a href="pcredemo.html"><b>pcredemo</b></a> +documentation, and the +<a href="pcresample.html"><b>pcresample</b></a> +documentation describes how to compile and run it. +</P> +<P> +Just-in-time compiler support is an optional feature of PCRE that can be built +in appropriate hardware environments. It greatly speeds up the matching +performance of many patterns. Simple programs can easily request that it be +used if available, by setting an option that is ignored when it is not +relevant. More complicated programs might need to make use of the functions +<b>pcre_jit_stack_alloc()</b>, <b>pcre_jit_stack_free()</b>, and +<b>pcre_assign_jit_stack()</b> in order to control the JIT code's memory usage. +</P> +<P> +From release 8.32 there is also a direct interface for JIT execution, which +gives improved performance. The JIT-specific functions are discussed in the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation. +</P> +<P> +A second matching function, <b>pcre_dfa_exec()</b>, which is not +Perl-compatible, is also provided. This uses a different algorithm for the +matching. The alternative algorithm finds all possible matches (at a given +point in the subject), and scans the subject just once (unless there are +lookbehind assertions). However, this algorithm does not return captured +substrings. A description of the two matching algorithms and their advantages +and disadvantages is given in the +<a href="pcrematching.html"><b>pcrematching</b></a> +documentation. +</P> +<P> +In addition to the main compiling and matching functions, there are convenience +functions for extracting captured substrings from a subject string that is +matched by <b>pcre_exec()</b>. They are: +<pre> + <b>pcre_copy_substring()</b> + <b>pcre_copy_named_substring()</b> + <b>pcre_get_substring()</b> + <b>pcre_get_named_substring()</b> + <b>pcre_get_substring_list()</b> + <b>pcre_get_stringnumber()</b> + <b>pcre_get_stringtable_entries()</b> +</pre> +<b>pcre_free_substring()</b> and <b>pcre_free_substring_list()</b> are also +provided, to free the memory used for extracted strings. +</P> +<P> +The function <b>pcre_maketables()</b> is used to build a set of character tables +in the current locale for passing to <b>pcre_compile()</b>, <b>pcre_exec()</b>, +or <b>pcre_dfa_exec()</b>. This is an optional facility that is provided for +specialist use. Most commonly, no special tables are passed, in which case +internal tables that are generated when PCRE is built are used. +</P> +<P> +The function <b>pcre_fullinfo()</b> is used to find out information about a +compiled pattern. The function <b>pcre_version()</b> returns a pointer to a +string containing the version of PCRE and its date of release. +</P> +<P> +The function <b>pcre_refcount()</b> maintains a reference count in a data block +containing a compiled pattern. This is provided for the benefit of +object-oriented applications. +</P> +<P> +The global variables <b>pcre_malloc</b> and <b>pcre_free</b> initially contain +the entry points of the standard <b>malloc()</b> and <b>free()</b> functions, +respectively. PCRE calls the memory management functions via these variables, +so a calling program can replace them if it wishes to intercept the calls. This +should be done before calling any PCRE functions. +</P> +<P> +The global variables <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> are also +indirections to memory management functions. These special functions are used +only when PCRE is compiled to use the heap for remembering data, instead of +recursive function calls, when running the <b>pcre_exec()</b> function. See the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation for details of how to do this. It is a non-standard way of +building PCRE, for use in environments that have limited stacks. Because of the +greater use of memory management, it runs more slowly. Separate functions are +provided so that special-purpose external code can be used for this case. When +used, these functions are always called in a stack-like manner (last obtained, +first freed), and always for memory blocks of the same size. There is a +discussion about PCRE's stack usage in the +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation. +</P> +<P> +The global variable <b>pcre_callout</b> initially contains NULL. It can be set +by the caller to a "callout" function, which PCRE will then call at specified +points during a matching operation. Details are given in the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +</P> +<P> +The global variable <b>pcre_stack_guard</b> initially contains NULL. It can be +set by the caller to a function that is called by PCRE whenever it starts +to compile a parenthesized part of a pattern. When parentheses are nested, PCRE +uses recursive function calls, which use up the system stack. This function is +provided so that applications with restricted stacks can force a compilation +error if the stack runs out. The function should return zero if all is well, or +non-zero to force an error. +<a name="newlines"></a></P> +<br><a name="SEC7" href="#TOC1">NEWLINES</a><br> +<P> +PCRE supports five different conventions for indicating line breaks in +strings: a single CR (carriage return) character, a single LF (linefeed) +character, the two-character sequence CRLF, any of the three preceding, or any +Unicode newline sequence. The Unicode newline sequences are the three just +mentioned, plus the single characters VT (vertical tab, U+000B), FF (form feed, +U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS +(paragraph separator, U+2029). +</P> +<P> +Each of the first three conventions is used by at least one operating system as +its standard newline sequence. When PCRE is built, a default can be specified. +The default default is LF, which is the Unix standard. When PCRE is run, the +default can be overridden, either when a pattern is compiled, or when it is +matched. +</P> +<P> +At compile time, the newline convention can be specified by the <i>options</i> +argument of <b>pcre_compile()</b>, or it can be specified by special text at the +start of the pattern itself; this overrides any other settings. See the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +page for details of the special character sequences. +</P> +<P> +In the PCRE documentation the word "newline" is used to mean "the character or +pair of characters that indicate a line break". The choice of newline +convention affects the handling of the dot, circumflex, and dollar +metacharacters, the handling of #-comments in /x mode, and, when CRLF is a +recognized line ending sequence, the match position advancement for a +non-anchored pattern. There is more detail about this in the +<a href="#execoptions">section on <b>pcre_exec()</b> options</a> +below. +</P> +<P> +The choice of newline convention does not affect the interpretation of +the \n or \r escape sequences, nor does it affect what \R matches, which is +controlled in a similar way, but by separate options. +</P> +<br><a name="SEC8" href="#TOC1">MULTITHREADING</a><br> +<P> +The PCRE functions can be used in multi-threading applications, with the +proviso that the memory management functions pointed to by <b>pcre_malloc</b>, +<b>pcre_free</b>, <b>pcre_stack_malloc</b>, and <b>pcre_stack_free</b>, and the +callout and stack-checking functions pointed to by <b>pcre_callout</b> and +<b>pcre_stack_guard</b>, are shared by all threads. +</P> +<P> +The compiled form of a regular expression is not altered during matching, so +the same compiled pattern can safely be used by several threads at once. +</P> +<P> +If the just-in-time optimization feature is being used, it needs separate +memory stack areas for each thread. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for more details. +</P> +<br><a name="SEC9" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br> +<P> +The compiled form of a regular expression can be saved and re-used at a later +time, possibly by a different program, and even on a host other than the one on +which it was compiled. Details are given in the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation, which includes a description of the +<b>pcre_pattern_to_host_byte_order()</b> function. However, compiling a regular +expression with one version of PCRE for use with a different version is not +guaranteed to work and may cause crashes. +</P> +<br><a name="SEC10" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br> +<P> +<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> +</P> +<P> +The function <b>pcre_config()</b> makes it possible for a PCRE client to +discover which optional features have been compiled into the PCRE library. The +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation has more details about these optional features. +</P> +<P> +The first argument for <b>pcre_config()</b> is an integer, specifying which +information is required; the second argument is a pointer to a variable into +which the information is placed. The returned value is zero on success, or the +negative error code PCRE_ERROR_BADOPTION if the value in the first argument is +not recognized. The following information is available: +<pre> + PCRE_CONFIG_UTF8 +</pre> +The output is an integer that is set to one if UTF-8 support is available; +otherwise it is set to zero. This value should normally be given to the 8-bit +version of this function, <b>pcre_config()</b>. If it is given to the 16-bit +or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION. +<pre> + PCRE_CONFIG_UTF16 +</pre> +The output is an integer that is set to one if UTF-16 support is available; +otherwise it is set to zero. This value should normally be given to the 16-bit +version of this function, <b>pcre16_config()</b>. If it is given to the 8-bit +or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION. +<pre> + PCRE_CONFIG_UTF32 +</pre> +The output is an integer that is set to one if UTF-32 support is available; +otherwise it is set to zero. This value should normally be given to the 32-bit +version of this function, <b>pcre32_config()</b>. If it is given to the 8-bit +or 16-bit version of this function, the result is PCRE_ERROR_BADOPTION. +<pre> + PCRE_CONFIG_UNICODE_PROPERTIES +</pre> +The output is an integer that is set to one if support for Unicode character +properties is available; otherwise it is set to zero. +<pre> + PCRE_CONFIG_JIT +</pre> +The output is an integer that is set to one if support for just-in-time +compiling is available; otherwise it is set to zero. +<pre> + PCRE_CONFIG_JITTARGET +</pre> +The output is a pointer to a zero-terminated "const char *" string. If JIT +support is available, the string contains the name of the architecture for +which the JIT compiler is configured, for example "x86 32bit (little endian + +unaligned)". If JIT support is not available, the result is NULL. +<pre> + PCRE_CONFIG_NEWLINE +</pre> +The output is an integer whose value specifies the default character sequence +that is recognized as meaning "newline". The values that are supported in +ASCII/Unicode environments are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for +ANYCRLF, and -1 for ANY. In EBCDIC environments, CR, ANYCRLF, and ANY yield the +same values. However, the value for LF is normally 21, though some EBCDIC +environments use 37. The corresponding values for CRLF are 3349 and 3365. The +default should normally correspond to the standard sequence for your operating +system. +<pre> + PCRE_CONFIG_BSR +</pre> +The output is an integer whose value indicates what character sequences the \R +escape sequence matches by default. A value of 0 means that \R matches any +Unicode line ending sequence; a value of 1 means that \R matches only CR, LF, +or CRLF. The default can be overridden when a pattern is compiled or matched. +<pre> + PCRE_CONFIG_LINK_SIZE +</pre> +The output is an integer that contains the number of bytes used for internal +linkage in compiled regular expressions. For the 8-bit library, the value can +be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still +a number of bytes. For the 32-bit library, the value is either 2 or 4 and is +still a number of bytes. The default value of 2 is sufficient for all but the +most massive patterns, since it allows the compiled pattern to be up to 64K in +size. Larger values allow larger regular expressions to be compiled, at the +expense of slower matching. +<pre> + PCRE_CONFIG_POSIX_MALLOC_THRESHOLD +</pre> +The output is an integer that contains the threshold above which the POSIX +interface uses <b>malloc()</b> for output vectors. Further details are given in +the +<a href="pcreposix.html"><b>pcreposix</b></a> +documentation. +<pre> + PCRE_CONFIG_PARENS_LIMIT +</pre> +The output is a long integer that gives the maximum depth of nesting of +parentheses (of any kind) in a pattern. This limit is imposed to cap the amount +of system stack used when a pattern is compiled. It is specified when PCRE is +built; the default is 250. This limit does not take into account the stack that +may already be used by the calling application. For finer control over +compilation stack usage, you can set a pointer to an external checking function +in <b>pcre_stack_guard</b>. +<pre> + PCRE_CONFIG_MATCH_LIMIT +</pre> +The output is a long integer that gives the default limit for the number of +internal matching function calls in a <b>pcre_exec()</b> execution. Further +details are given with <b>pcre_exec()</b> below. +<pre> + PCRE_CONFIG_MATCH_LIMIT_RECURSION +</pre> +The output is a long integer that gives the default limit for the depth of +recursion when calling the internal matching function in a <b>pcre_exec()</b> +execution. Further details are given with <b>pcre_exec()</b> below. +<pre> + PCRE_CONFIG_STACKRECURSE +</pre> +The output is an integer that is set to one if internal recursion when running +<b>pcre_exec()</b> is implemented by recursive function calls that use the stack +to remember their state. This is the usual way that PCRE is compiled. The +output is zero if PCRE was compiled to use blocks of data on the heap instead +of recursive function calls. In this case, <b>pcre_stack_malloc</b> and +<b>pcre_stack_free</b> are called to manage memory blocks on the heap, thus +avoiding the use of the stack. +</P> +<br><a name="SEC11" href="#TOC1">COMPILING A PATTERN</a><br> +<P> +<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> +<b>pcre *pcre_compile2(const char *<i>pattern</i>, int <i>options</i>,</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +</P> +<P> +Either of the functions <b>pcre_compile()</b> or <b>pcre_compile2()</b> can be +called to compile a pattern into an internal form. The only difference between +the two interfaces is that <b>pcre_compile2()</b> has an additional argument, +<i>errorcodeptr</i>, via which a numerical error code can be returned. To avoid +too much repetition, we refer just to <b>pcre_compile()</b> below, but the +information applies equally to <b>pcre_compile2()</b>. +</P> +<P> +The pattern is a C string terminated by a binary zero, and is passed in the +<i>pattern</i> argument. A pointer to a single block of memory that is obtained +via <b>pcre_malloc</b> is returned. This contains the compiled code and related +data. The <b>pcre</b> type is defined for the returned block; this is a typedef +for a structure whose contents are not externally defined. It is up to the +caller to free the memory (via <b>pcre_free</b>) when it is no longer required. +</P> +<P> +Although the compiled code of a PCRE regex is relocatable, that is, it does not +depend on memory location, the complete <b>pcre</b> data block is not +fully relocatable, because it may contain a copy of the <i>tableptr</i> +argument, which is an address (see below). +</P> +<P> +The <i>options</i> argument contains various bit settings that affect the +compilation. It should be zero if no options are required. The available +options are described below. Some of them (in particular, those that are +compatible with Perl, but some others as well) can also be set and unset from +within the pattern (see the detailed description in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation). For those options that can be different in different parts of +the pattern, the contents of the <i>options</i> argument specifies their +settings at the start of compilation and execution. The PCRE_ANCHORED, +PCRE_BSR_<i>xxx</i>, PCRE_NEWLINE_<i>xxx</i>, PCRE_NO_UTF8_CHECK, and +PCRE_NO_START_OPTIMIZE options can be set at the time of matching as well as at +compile time. +</P> +<P> +If <i>errptr</i> is NULL, <b>pcre_compile()</b> returns NULL immediately. +Otherwise, if compilation of a pattern fails, <b>pcre_compile()</b> returns +NULL, and sets the variable pointed to by <i>errptr</i> to point to a textual +error message. This is a static string that is part of the library. You must +not try to free it. Normally, the offset from the start of the pattern to the +data unit that was being processed when the error was discovered is placed in +the variable pointed to by <i>erroffset</i>, which must not be NULL (if it is, +an immediate error is given). However, for an invalid UTF-8 or UTF-16 string, +the offset is that of the first data unit of the failing character. +</P> +<P> +Some errors are not detected until the whole pattern has been scanned; in these +cases, the offset passed back is the length of the pattern. Note that the +offset is in data units, not characters, even in a UTF mode. It may sometimes +point into the middle of a UTF-8 or UTF-16 character. +</P> +<P> +If <b>pcre_compile2()</b> is used instead of <b>pcre_compile()</b>, and the +<i>errorcodeptr</i> argument is not NULL, a non-zero error code number is +returned via this argument in the event of an error. This is in addition to the +textual error message. Error codes and messages are listed below. +</P> +<P> +If the final argument, <i>tableptr</i>, is NULL, PCRE uses a default set of +character tables that are built when PCRE is compiled, using the default C +locale. Otherwise, <i>tableptr</i> must be an address that is the result of a +call to <b>pcre_maketables()</b>. This value is stored with the compiled +pattern, and used again by <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b> when the +pattern is matched. For more discussion, see the section on locale support +below. +</P> +<P> +This code fragment shows a typical straightforward call to <b>pcre_compile()</b>: +<pre> + pcre *re; + const char *error; + int erroffset; + re = pcre_compile( + "^A.*Z", /* the pattern */ + 0, /* default options */ + &error, /* for error message */ + &erroffset, /* for error offset */ + NULL); /* use default character tables */ +</pre> +The following names for option bits are defined in the <b>pcre.h</b> header +file: +<pre> + PCRE_ANCHORED +</pre> +If this bit is set, the pattern is forced to be "anchored", that is, it is +constrained to match only at the first matching point in the string that is +being searched (the "subject string"). This effect can also be achieved by +appropriate constructs in the pattern itself, which is the only way to do it in +Perl. +<pre> + PCRE_AUTO_CALLOUT +</pre> +If this bit is set, <b>pcre_compile()</b> automatically inserts callout items, +all with number 255, before each pattern item. For discussion of the callout +facility, see the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +<pre> + PCRE_BSR_ANYCRLF + PCRE_BSR_UNICODE +</pre> +These options (which are mutually exclusive) control what the \R escape +sequence matches. The choice is either to match only CR, LF, or CRLF, or to +match any Unicode newline sequence. The default is specified when PCRE is +built. It can be overridden from within the pattern, or by setting an option +when a compiled pattern is matched. +<pre> + PCRE_CASELESS +</pre> +If this bit is set, letters in the pattern match both upper and lower case +letters. It is equivalent to Perl's /i option, and it can be changed within a +pattern by a (?i) option setting. In UTF-8 mode, PCRE always understands the +concept of case for characters whose values are less than 128, so caseless +matching is always possible. For characters with higher values, the concept of +case is supported if PCRE is compiled with Unicode property support, but not +otherwise. If you want to use caseless matching for characters 128 and above, +you must ensure that PCRE is compiled with Unicode property support as well as +with UTF-8 support. +<pre> + PCRE_DOLLAR_ENDONLY +</pre> +If this bit is set, a dollar metacharacter in the pattern matches only at the +end of the subject string. Without this option, a dollar also matches +immediately before a newline at the end of the string (but not before any other +newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set. +There is no equivalent to this option in Perl, and no way to set it within a +pattern. +<pre> + PCRE_DOTALL +</pre> +If this bit is set, a dot metacharacter in the pattern matches a character of +any value, including one that indicates a newline. However, it only ever +matches one character, even if newlines are coded as CRLF. Without this option, +a dot does not match when the current position is at a newline. This option is +equivalent to Perl's /s option, and it can be changed within a pattern by a +(?s) option setting. A negative class such as [^a] always matches newline +characters, independent of the setting of this option. +<pre> + PCRE_DUPNAMES +</pre> +If this bit is set, names used to identify capturing subpatterns need not be +unique. This can be helpful for certain types of pattern when it is known that +only one instance of the named subpattern can ever be matched. There are more +details of named subpatterns below; see also the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. +<pre> + PCRE_EXTENDED +</pre> +If this bit is set, most white space characters in the pattern are totally +ignored except when escaped or inside a character class. However, white space +is not allowed within sequences such as (?> that introduce various +parenthesized subpatterns, nor within a numerical quantifier such as {1,3}. +However, ignorable white space is permitted between an item and a following +quantifier and between a quantifier and a following + that indicates +possessiveness. +</P> +<P> +White space did not used to include the VT character (code 11), because Perl +did not treat this character as white space. However, Perl changed at release +5.18, so PCRE followed at release 8.34, and VT is now treated as white space. +</P> +<P> +PCRE_EXTENDED also causes characters between an unescaped # outside a character +class and the next newline, inclusive, to be ignored. PCRE_EXTENDED is +equivalent to Perl's /x option, and it can be changed within a pattern by a +(?x) option setting. +</P> +<P> +Which characters are interpreted as newlines is controlled by the options +passed to <b>pcre_compile()</b> or by a special sequence at the start of the +pattern, as described in the section entitled +<a href="pcrepattern.html#newlines">"Newline conventions"</a> +in the <b>pcrepattern</b> documentation. Note that the end of this type of +comment is a literal newline sequence in the pattern; escape sequences that +happen to represent a newline do not count. +</P> +<P> +This option makes it possible to include comments inside complicated patterns. +Note, however, that this applies only to data characters. White space characters +may never appear within special character sequences in a pattern, for example +within the sequence (?( that introduces a conditional subpattern. +<pre> + PCRE_EXTRA +</pre> +This option was invented in order to turn on additional functionality of PCRE +that is incompatible with Perl, but it is currently of very little use. When +set, any backslash in a pattern that is followed by a letter that has no +special meaning causes an error, thus reserving these combinations for future +expansion. By default, as in Perl, a backslash followed by a letter with no +special meaning is treated as a literal. (Perl can, however, be persuaded to +give an error for this, by running it with the -w option.) There are at present +no other features controlled by this option. It can also be set by a (?X) +option setting within a pattern. +<pre> + PCRE_FIRSTLINE +</pre> +If this option is set, an unanchored pattern is required to match before or at +the first newline in the subject string, though the matched text may continue +over the newline. +<pre> + PCRE_JAVASCRIPT_COMPAT +</pre> +If this option is set, PCRE's behaviour is changed in some ways so that it is +compatible with JavaScript rather than Perl. The changes are as follows: +</P> +<P> +(1) A lone closing square bracket in a pattern causes a compile-time error, +because this is illegal in JavaScript (by default it is treated as a data +character). Thus, the pattern AB]CD becomes illegal when this option is set. +</P> +<P> +(2) At run time, a back reference to an unset subpattern group matches an empty +string (by default this causes the current matching alternative to fail). A +pattern such as (\1)(a) succeeds when this option is set (assuming it can find +an "a" in the subject), whereas it fails by default, for Perl compatibility. +</P> +<P> +(3) \U matches an upper case "U" character; by default \U causes a compile +time error (Perl uses \U to upper case subsequent characters). +</P> +<P> +(4) \u matches a lower case "u" character unless it is followed by four +hexadecimal digits, in which case the hexadecimal number defines the code point +to match. By default, \u causes a compile time error (Perl uses it to upper +case the following character). +</P> +<P> +(5) \x matches a lower case "x" character unless it is followed by two +hexadecimal digits, in which case the hexadecimal number defines the code point +to match. By default, as in Perl, a hexadecimal number is always expected after +\x, but it may have zero, one, or two digits (so, for example, \xz matches a +binary zero character followed by z). +<pre> + PCRE_MULTILINE +</pre> +By default, for the purposes of matching "start of line" and "end of line", +PCRE treats the subject string as consisting of a single line of characters, +even if it actually contains newlines. The "start of line" metacharacter (^) +matches only at the start of the string, and the "end of line" metacharacter +($) matches only at the end of the string, or before a terminating newline +(except when PCRE_DOLLAR_ENDONLY is set). Note, however, that unless +PCRE_DOTALL is set, the "any character" metacharacter (.) does not match at a +newline. This behaviour (for ^, $, and dot) is the same as Perl. +</P> +<P> +When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs +match immediately following or immediately before internal newlines in the +subject string, respectively, as well as at the very start and end. This is +equivalent to Perl's /m option, and it can be changed within a pattern by a +(?m) option setting. If there are no newlines in a subject string, or no +occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect. +<pre> + PCRE_NEVER_UTF +</pre> +This option locks out interpretation of the pattern as UTF-8 (or UTF-16 or +UTF-32 in the 16-bit and 32-bit libraries). In particular, it prevents the +creator of the pattern from switching to UTF interpretation by starting the +pattern with (*UTF). This may be useful in applications that process patterns +from external sources. The combination of PCRE_UTF8 and PCRE_NEVER_UTF also +causes an error. +<pre> + PCRE_NEWLINE_CR + PCRE_NEWLINE_LF + PCRE_NEWLINE_CRLF + PCRE_NEWLINE_ANYCRLF + PCRE_NEWLINE_ANY +</pre> +These options override the default newline definition that was chosen when PCRE +was built. Setting the first or the second specifies that a newline is +indicated by a single character (CR or LF, respectively). Setting +PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character +CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three +preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies +that any Unicode newline sequence should be recognized. +</P> +<P> +In an ASCII/Unicode environment, the Unicode newline sequences are the three +just mentioned, plus the single characters VT (vertical tab, U+000B), FF (form +feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS +(paragraph separator, U+2029). For the 8-bit library, the last two are +recognized only in UTF-8 mode. +</P> +<P> +When PCRE is compiled to run in an EBCDIC (mainframe) environment, the code for +CR is 0x0d, the same as ASCII. However, the character code for LF is normally +0x15, though in some EBCDIC environments 0x25 is used. Whichever of these is +not LF is made to correspond to Unicode's NEL character. EBCDIC codes are all +less than 256. For more details, see the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation. +</P> +<P> +The newline setting in the options word uses three bits that are treated +as a number, giving eight possibilities. Currently only six are used (default +plus the five values above). This means that if you set more than one newline +option, the combination may or may not be sensible. For example, +PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but +other combinations may yield unused numbers and cause an error. +</P> +<P> +The only time that a line break in a pattern is specially recognized when +compiling is when PCRE_EXTENDED is set. CR and LF are white space characters, +and so are ignored in this mode. Also, an unescaped # outside a character class +indicates a comment that lasts until after the next line break sequence. In +other circumstances, line break sequences in patterns are treated as literal +data. +</P> +<P> +The newline option that is set at compile time becomes the default that is used +for <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, but it can be overridden. +<pre> + PCRE_NO_AUTO_CAPTURE +</pre> +If this option is set, it disables the use of numbered capturing parentheses in +the pattern. Any opening parenthesis that is not followed by ? behaves as if it +were followed by ?: but named parentheses can still be used for capturing (and +they acquire numbers in the usual way). There is no equivalent of this option +in Perl. +<pre> + PCRE_NO_AUTO_POSSESS +</pre> +If this option is set, it disables "auto-possessification". This is an +optimization that, for example, turns a+b into a++b in order to avoid +backtracks into a+ that can never be successful. However, if callouts are in +use, auto-possessification means that some of them are never taken. You can set +this option if you want the matching functions to do a full unoptimized search +and run all the callouts, but it is mainly provided for testing purposes. +<pre> + PCRE_NO_START_OPTIMIZE +</pre> +This is an option that acts at matching time; that is, it is really an option +for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. If it is set at compile time, +it is remembered with the compiled pattern and assumed at matching time. This +is necessary if you want to use JIT execution, because the JIT compiler needs +to know whether or not this option is set. For details see the discussion of +PCRE_NO_START_OPTIMIZE +<a href="#execoptions">below.</a> +<pre> + PCRE_UCP +</pre> +This option changes the way PCRE processes \B, \b, \D, \d, \S, \s, \W, +\w, and some of the POSIX character classes. By default, only ASCII characters +are recognized, but if PCRE_UCP is set, Unicode properties are used instead to +classify characters. More details are given in the section on +<a href="pcre.html#genericchartypes">generic character types</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +page. If you set PCRE_UCP, matching one of the items it affects takes much +longer. The option is available only if PCRE has been compiled with Unicode +property support. +<pre> + PCRE_UNGREEDY +</pre> +This option inverts the "greediness" of the quantifiers so that they are not +greedy by default, but become greedy if followed by "?". It is not compatible +with Perl. It can also be set by a (?U) option setting within the pattern. +<pre> + PCRE_UTF8 +</pre> +This option causes PCRE to regard both the pattern and the subject as strings +of UTF-8 characters instead of single-byte strings. However, it is available +only when PCRE is built to include UTF support. If not, the use of this option +provokes an error. Details of how this option changes the behaviour of PCRE are +given in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. +<pre> + PCRE_NO_UTF8_CHECK +</pre> +When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is +automatically checked. There is a discussion about the +<a href="pcreunicode.html#utf8strings">validity of UTF-8 strings</a> +in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. If an invalid UTF-8 sequence is found, <b>pcre_compile()</b> returns an +error. If you already know that your pattern is valid, and you want to skip +this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK option. +When it is set, the effect of passing an invalid UTF-8 string as a pattern is +undefined. It may cause your program to crash or loop. Note that this option +can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress +the validity checking of subject strings only. If the same string is being +matched many times, the option can be safely set for the second and subsequent +matchings to improve performance. +</P> +<br><a name="SEC12" href="#TOC1">COMPILATION ERROR CODES</a><br> +<P> +The following table lists the error codes than may be returned by +<b>pcre_compile2()</b>, along with the error messages that may be returned by +both compiling functions. Note that error messages are always 8-bit ASCII +strings, even in 16-bit or 32-bit mode. As PCRE has developed, some error codes +have fallen out of use. To avoid confusion, they have not been re-used. +<pre> + 0 no error + 1 \ at end of pattern + 2 \c at end of pattern + 3 unrecognized character follows \ + 4 numbers out of order in {} quantifier + 5 number too big in {} quantifier + 6 missing terminating ] for character class + 7 invalid escape sequence in character class + 8 range out of order in character class + 9 nothing to repeat + 10 [this code is not in use] + 11 internal error: unexpected repeat + 12 unrecognized character after (? or (?- + 13 POSIX named classes are supported only within a class + 14 missing ) + 15 reference to non-existent subpattern + 16 erroffset passed as NULL + 17 unknown option bit(s) set + 18 missing ) after comment + 19 [this code is not in use] + 20 regular expression is too large + 21 failed to get memory + 22 unmatched parentheses + 23 internal error: code overflow + 24 unrecognized character after (?< + 25 lookbehind assertion is not fixed length + 26 malformed number or name after (?( + 27 conditional group contains more than two branches + 28 assertion expected after (?( + 29 (?R or (?[+-]digits must be followed by ) + 30 unknown POSIX class name + 31 POSIX collating elements are not supported + 32 this version of PCRE is compiled without UTF support + 33 [this code is not in use] + 34 character value in \x{} or \o{} is too large + 35 invalid condition (?(0) + 36 \C not allowed in lookbehind assertion + 37 PCRE does not support \L, \l, \N{name}, \U, or \u + 38 number after (?C is > 255 + 39 closing ) for (?C expected + 40 recursive call could loop indefinitely + 41 unrecognized character after (?P + 42 syntax error in subpattern name (missing terminator) + 43 two named subpatterns have the same name + 44 invalid UTF-8 string (specifically UTF-8) + 45 support for \P, \p, and \X has not been compiled + 46 malformed \P or \p sequence + 47 unknown property name after \P or \p + 48 subpattern name is too long (maximum 32 characters) + 49 too many named subpatterns (maximum 10000) + 50 [this code is not in use] + 51 octal value is greater than \377 in 8-bit non-UTF-8 mode + 52 internal error: overran compiling workspace + 53 internal error: previously-checked referenced subpattern + not found + 54 DEFINE group contains more than one branch + 55 repeating a DEFINE group is not allowed + 56 inconsistent NEWLINE options + 57 \g is not followed by a braced, angle-bracketed, or quoted + name/number or by a plain number + 58 a numbered reference must not be zero + 59 an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT) + 60 (*VERB) not recognized or malformed + 61 number is too big + 62 subpattern name expected + 63 digit expected after (?+ + 64 ] is an invalid data character in JavaScript compatibility mode + 65 different names for subpatterns of the same number are + not allowed + 66 (*MARK) must have an argument + 67 this version of PCRE is not compiled with Unicode property + support + 68 \c must be followed by an ASCII character + 69 \k is not followed by a braced, angle-bracketed, or quoted name + 70 internal error: unknown opcode in find_fixedlength() + 71 \N is not supported in a class + 72 too many forward references + 73 disallowed Unicode code point (>= 0xd800 && <= 0xdfff) + 74 invalid UTF-16 string (specifically UTF-16) + 75 name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN) + 76 character value in \u.... sequence is too large + 77 invalid UTF-32 string (specifically UTF-32) + 78 setting UTF is disabled by the application + 79 non-hex character in \x{} (closing brace missing?) + 80 non-octal character in \o{} (closing brace missing?) + 81 missing opening brace after \o + 82 parentheses are too deeply nested + 83 invalid range in character class + 84 group name must start with a non-digit + 85 parentheses are too deeply nested (stack check) +</pre> +The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may +be used if the limits were changed when PCRE was built. +<a name="studyingapattern"></a></P> +<br><a name="SEC13" href="#TOC1">STUDYING A PATTERN</a><br> +<P> +<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> +<b> const char **<i>errptr</i>);</b> +</P> +<P> +If a compiled pattern is going to be used several times, it is worth spending +more time analyzing it in order to speed up the time taken for matching. The +function <b>pcre_study()</b> takes a pointer to a compiled pattern as its first +argument. If studying the pattern produces additional information that will +help speed up matching, <b>pcre_study()</b> returns a pointer to a +<b>pcre_extra</b> block, in which the <i>study_data</i> field points to the +results of the study. +</P> +<P> +The returned value from <b>pcre_study()</b> can be passed directly to +<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. However, a <b>pcre_extra</b> block +also contains other fields that can be set by the caller before the block is +passed; these are described +<a href="#extradata">below</a> +in the section on matching a pattern. +</P> +<P> +If studying the pattern does not produce any useful information, +<b>pcre_study()</b> returns NULL by default. In that circumstance, if the +calling program wants to pass any of the other fields to <b>pcre_exec()</b> or +<b>pcre_dfa_exec()</b>, it must set up its own <b>pcre_extra</b> block. However, +if <b>pcre_study()</b> is called with the PCRE_STUDY_EXTRA_NEEDED option, it +returns a <b>pcre_extra</b> block even if studying did not find any additional +information. It may still return NULL, however, if an error occurs in +<b>pcre_study()</b>. +</P> +<P> +The second argument of <b>pcre_study()</b> contains option bits. There are three +further options in addition to PCRE_STUDY_EXTRA_NEEDED: +<pre> + PCRE_STUDY_JIT_COMPILE + PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE + PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE +</pre> +If any of these are set, and the just-in-time compiler is available, the +pattern is further compiled into machine code that executes much faster than +the <b>pcre_exec()</b> interpretive matching function. If the just-in-time +compiler is not available, these options are ignored. All undefined bits in the +<i>options</i> argument must be zero. +</P> +<P> +JIT compilation is a heavyweight optimization. It can take some time for +patterns to be analyzed, and for one-off matches and simple patterns the +benefit of faster execution might be offset by a much slower study time. +Not all patterns can be optimized by the JIT compiler. For those that cannot be +handled, matching automatically falls back to the <b>pcre_exec()</b> +interpreter. For more details, see the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation. +</P> +<P> +The third argument for <b>pcre_study()</b> is a pointer for an error message. If +studying succeeds (even if no data is returned), the variable it points to is +set to NULL. Otherwise it is set to point to a textual error message. This is a +static string that is part of the library. You must not try to free it. You +should test the error pointer for NULL after calling <b>pcre_study()</b>, to be +sure that it has run successfully. +</P> +<P> +When you are finished with a pattern, you can free the memory used for the +study data by calling <b>pcre_free_study()</b>. This function was added to the +API for release 8.20. For earlier versions, the memory could be freed with +<b>pcre_free()</b>, just like the pattern itself. This will still work in cases +where JIT optimization is not used, but it is advisable to change to the new +function when convenient. +</P> +<P> +This is a typical way in which <b>pcre_study</b>() is used (except that in a +real application there should be tests for errors): +<pre> + int rc; + pcre *re; + pcre_extra *sd; + re = pcre_compile("pattern", 0, &error, &erroroffset, NULL); + sd = pcre_study( + re, /* result of pcre_compile() */ + 0, /* no options */ + &error); /* set to NULL or points to a message */ + rc = pcre_exec( /* see below for details of pcre_exec() options */ + re, sd, "subject", 7, 0, 0, ovector, 30); + ... + pcre_free_study(sd); + pcre_free(re); +</pre> +Studying a pattern does two things: first, a lower bound for the length of +subject string that is needed to match the pattern is computed. This does not +mean that there are any strings of that length that match, but it does +guarantee that no shorter strings match. The value is used to avoid wasting +time by trying to match strings that are shorter than the lower bound. You can +find out the value in a calling program via the <b>pcre_fullinfo()</b> function. +</P> +<P> +Studying a pattern is also useful for non-anchored patterns that do not have a +single fixed starting character. A bitmap of possible starting bytes is +created. This speeds up finding a position in the subject at which to start +matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256. +In 32-bit mode, the bitmap is used for 32-bit values less than 256.) +</P> +<P> +These two optimizations apply to both <b>pcre_exec()</b> and +<b>pcre_dfa_exec()</b>, and the information is also used by the JIT compiler. +The optimizations can be disabled by setting the PCRE_NO_START_OPTIMIZE option. +You might want to do this if your pattern contains callouts or (*MARK) and you +want to make use of these facilities in cases where matching fails. +</P> +<P> +PCRE_NO_START_OPTIMIZE can be specified at either compile time or execution +time. However, if PCRE_NO_START_OPTIMIZE is passed to <b>pcre_exec()</b>, (that +is, after any JIT compilation has happened) JIT execution is disabled. For JIT +execution to work with PCRE_NO_START_OPTIMIZE, the option must be set at +compile time. +</P> +<P> +There is a longer discussion of PCRE_NO_START_OPTIMIZE +<a href="#execoptions">below.</a> +<a name="localesupport"></a></P> +<br><a name="SEC14" href="#TOC1">LOCALE SUPPORT</a><br> +<P> +PCRE handles caseless matching, and determines whether characters are letters, +digits, or whatever, by reference to a set of tables, indexed by character +code point. When running in UTF-8 mode, or in the 16- or 32-bit libraries, this +applies only to characters with code points less than 256. By default, +higher-valued code points never match escapes such as \w or \d. However, if +PCRE is built with Unicode property support, all characters can be tested with +\p and \P, or, alternatively, the PCRE_UCP option can be set when a pattern +is compiled; this causes \w and friends to use Unicode property support +instead of the built-in tables. +</P> +<P> +The use of locales with Unicode is discouraged. If you are handling characters +with code points greater than 128, you should either use Unicode support, or +use locales, but not try to mix the two. +</P> +<P> +PCRE contains an internal set of tables that are used when the final argument +of <b>pcre_compile()</b> is NULL. These are sufficient for many applications. +Normally, the internal tables recognize only ASCII characters. However, when +PCRE is built, it is possible to cause the internal tables to be rebuilt in the +default "C" locale of the local system, which may cause them to be different. +</P> +<P> +The internal tables can always be overridden by tables supplied by the +application that calls PCRE. These may be created in a different locale from +the default. As more and more applications change to using Unicode, the need +for this locale support is expected to die away. +</P> +<P> +External tables are built by calling the <b>pcre_maketables()</b> function, +which has no arguments, in the relevant locale. The result can then be passed +to <b>pcre_compile()</b> as often as necessary. For example, to build and use +tables that are appropriate for the French locale (where accented characters +with values greater than 128 are treated as letters), the following code could +be used: +<pre> + setlocale(LC_CTYPE, "fr_FR"); + tables = pcre_maketables(); + re = pcre_compile(..., tables); +</pre> +The locale name "fr_FR" is used on Linux and other Unix-like systems; if you +are using Windows, the name for the French locale is "french". +</P> +<P> +When <b>pcre_maketables()</b> runs, the tables are built in memory that is +obtained via <b>pcre_malloc</b>. It is the caller's responsibility to ensure +that the memory containing the tables remains available for as long as it is +needed. +</P> +<P> +The pointer that is passed to <b>pcre_compile()</b> is saved with the compiled +pattern, and the same tables are used via this pointer by <b>pcre_study()</b> +and also by <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>. Thus, for any single +pattern, compilation, studying and matching all happen in the same locale, but +different patterns can be processed in different locales. +</P> +<P> +It is possible to pass a table pointer or NULL (indicating the use of the +internal tables) to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> (see the +discussion below in the section on matching a pattern). This facility is +provided for use with pre-compiled patterns that have been saved and reloaded. +Character tables are not saved with patterns, so if a non-standard table was +used at compile time, it must be provided again when the reloaded pattern is +matched. Attempting to use this facility to match a pattern in a different +locale from the one in which it was compiled is likely to lead to anomalous +(usually incorrect) results. +<a name="infoaboutpattern"></a></P> +<br><a name="SEC15" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br> +<P> +<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> int <i>what</i>, void *<i>where</i>);</b> +</P> +<P> +The <b>pcre_fullinfo()</b> function returns information about a compiled +pattern. It replaces the <b>pcre_info()</b> function, which was removed from the +library at version 8.30, after more than 10 years of obsolescence. +</P> +<P> +The first argument for <b>pcre_fullinfo()</b> is a pointer to the compiled +pattern. The second argument is the result of <b>pcre_study()</b>, or NULL if +the pattern was not studied. The third argument specifies which piece of +information is required, and the fourth argument is a pointer to a variable +to receive the data. The yield of the function is zero for success, or one of +the following negative numbers: +<pre> + PCRE_ERROR_NULL the argument <i>code</i> was NULL + the argument <i>where</i> was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + PCRE_ERROR_BADENDIANNESS the pattern was compiled with different + endianness + PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid + PCRE_ERROR_UNSET the requested field is not set +</pre> +The "magic number" is placed at the start of each compiled pattern as an simple +check against passing an arbitrary memory pointer. The endianness error can +occur if a compiled pattern is saved and reloaded on a different host. Here is +a typical call of <b>pcre_fullinfo()</b>, to obtain the length of the compiled +pattern: +<pre> + int rc; + size_t length; + rc = pcre_fullinfo( + re, /* result of pcre_compile() */ + sd, /* result of pcre_study(), or NULL */ + PCRE_INFO_SIZE, /* what is required */ + &length); /* where to put the data */ +</pre> +The possible values for the third argument are defined in <b>pcre.h</b>, and are +as follows: +<pre> + PCRE_INFO_BACKREFMAX +</pre> +Return the number of the highest back reference in the pattern. The fourth +argument should point to an <b>int</b> variable. Zero is returned if there are +no back references. +<pre> + PCRE_INFO_CAPTURECOUNT +</pre> +Return the number of capturing subpatterns in the pattern. The fourth argument +should point to an <b>int</b> variable. +<pre> + PCRE_INFO_DEFAULT_TABLES +</pre> +Return a pointer to the internal default character tables within PCRE. The +fourth argument should point to an <b>unsigned char *</b> variable. This +information call is provided for internal use by the <b>pcre_study()</b> +function. External callers can cause PCRE to use its internal tables by passing +a NULL table pointer. +<pre> + PCRE_INFO_FIRSTBYTE (deprecated) +</pre> +Return information about the first data unit of any matched string, for a +non-anchored pattern. The name of this option refers to the 8-bit library, +where data units are bytes. The fourth argument should point to an <b>int</b> +variable. Negative values are used for special cases. However, this means that +when the 32-bit library is in non-UTF-32 mode, the full 32-bit range of +characters cannot be returned. For this reason, this value is deprecated; use +PCRE_INFO_FIRSTCHARACTERFLAGS and PCRE_INFO_FIRSTCHARACTER instead. +</P> +<P> +If there is a fixed first value, for example, the letter "c" from a pattern +such as (cat|cow|coyote), its value is returned. In the 8-bit library, the +value is always less than 256. In the 16-bit library the value can be up to +0xffff. In the 32-bit library the value can be up to 0x10ffff. +</P> +<P> +If there is no fixed first value, and if either +<br> +<br> +(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch +starts with "^", or +<br> +<br> +(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set +(if it were set, the pattern would be anchored), +<br> +<br> +-1 is returned, indicating that the pattern matches only at the start of a +subject string or after any newline within the string. Otherwise -2 is +returned. For anchored patterns, -2 is returned. +<pre> + PCRE_INFO_FIRSTCHARACTER +</pre> +Return the value of the first data unit (non-UTF character) of any matched +string in the situation where PCRE_INFO_FIRSTCHARACTERFLAGS returns 1; +otherwise return 0. The fourth argument should point to an <b>uint_t</b> +variable. +</P> +<P> +In the 8-bit library, the value is always less than 256. In the 16-bit library +the value can be up to 0xffff. In the 32-bit library in UTF-32 mode the value +can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32 mode. +<pre> + PCRE_INFO_FIRSTCHARACTERFLAGS +</pre> +Return information about the first data unit of any matched string, for a +non-anchored pattern. The fourth argument should point to an <b>int</b> +variable. +</P> +<P> +If there is a fixed first value, for example, the letter "c" from a pattern +such as (cat|cow|coyote), 1 is returned, and the character value can be +retrieved using PCRE_INFO_FIRSTCHARACTER. If there is no fixed first value, and +if either +<br> +<br> +(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch +starts with "^", or +<br> +<br> +(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set +(if it were set, the pattern would be anchored), +<br> +<br> +2 is returned, indicating that the pattern matches only at the start of a +subject string or after any newline within the string. Otherwise 0 is +returned. For anchored patterns, 0 is returned. +<pre> + PCRE_INFO_FIRSTTABLE +</pre> +If the pattern was studied, and this resulted in the construction of a 256-bit +table indicating a fixed set of values for the first data unit in any matching +string, a pointer to the table is returned. Otherwise NULL is returned. The +fourth argument should point to an <b>unsigned char *</b> variable. +<pre> + PCRE_INFO_HASCRORLF +</pre> +Return 1 if the pattern contains any explicit matches for CR or LF characters, +otherwise 0. The fourth argument should point to an <b>int</b> variable. An +explicit match is either a literal CR or LF character, or \r or \n. +<pre> + PCRE_INFO_JCHANGED +</pre> +Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise +0. The fourth argument should point to an <b>int</b> variable. (?J) and +(?-J) set and unset the local PCRE_DUPNAMES option, respectively. +<pre> + PCRE_INFO_JIT +</pre> +Return 1 if the pattern was studied with one of the JIT options, and +just-in-time compiling was successful. The fourth argument should point to an +<b>int</b> variable. A return value of 0 means that JIT support is not available +in this version of PCRE, or that the pattern was not studied with a JIT option, +or that the JIT compiler could not handle this particular pattern. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for details of what can and cannot be handled. +<pre> + PCRE_INFO_JITSIZE +</pre> +If the pattern was successfully studied with a JIT option, return the size of +the JIT compiled code, otherwise return zero. The fourth argument should point +to a <b>size_t</b> variable. +<pre> + PCRE_INFO_LASTLITERAL +</pre> +Return the value of the rightmost literal data unit that must exist in any +matched string, other than at its start, if such a value has been recorded. The +fourth argument should point to an <b>int</b> variable. If there is no such +value, -1 is returned. For anchored patterns, a last literal value is recorded +only if it follows something of variable length. For example, for the pattern +/^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value +is -1. +</P> +<P> +Since for the 32-bit library using the non-UTF-32 mode, this function is unable +to return the full 32-bit range of characters, this value is deprecated; +instead the PCRE_INFO_REQUIREDCHARFLAGS and PCRE_INFO_REQUIREDCHAR values should +be used. +<pre> + PCRE_INFO_MATCH_EMPTY +</pre> +Return 1 if the pattern can match an empty string, otherwise 0. The fourth +argument should point to an <b>int</b> variable. +<pre> + PCRE_INFO_MATCHLIMIT +</pre> +If the pattern set a match limit by including an item of the form +(*LIMIT_MATCH=nnnn) at the start, the value is returned. The fourth argument +should point to an unsigned 32-bit integer. If no such value has been set, the +call to <b>pcre_fullinfo()</b> returns the error PCRE_ERROR_UNSET. +<pre> + PCRE_INFO_MAXLOOKBEHIND +</pre> +Return the number of characters (NB not data units) in the longest lookbehind +assertion in the pattern. This information is useful when doing multi-segment +matching using the partial matching facilities. Note that the simple assertions +\b and \B require a one-character lookbehind. \A also registers a +one-character lookbehind, though it does not actually inspect the previous +character. This is to ensure that at least one character from the old segment +is retained when a new segment is processed. Otherwise, if there are no +lookbehinds in the pattern, \A might match incorrectly at the start of a new +segment. +<pre> + PCRE_INFO_MINLENGTH +</pre> +If the pattern was studied and a minimum length for matching subject strings +was computed, its value is returned. Otherwise the returned value is -1. The +value is a number of characters, which in UTF mode may be different from the +number of data units. The fourth argument should point to an <b>int</b> +variable. A non-negative value is a lower bound to the length of any matching +string. There may not be any strings of that length that do actually match, but +every string that does match is at least that long. +<pre> + PCRE_INFO_NAMECOUNT + PCRE_INFO_NAMEENTRYSIZE + PCRE_INFO_NAMETABLE +</pre> +PCRE supports the use of named as well as numbered capturing parentheses. The +names are just an additional way of identifying the parentheses, which still +acquire numbers. Several convenience functions such as +<b>pcre_get_named_substring()</b> are provided for extracting captured +substrings by name. It is also possible to extract the data directly, by first +converting the name to a number in order to access the correct pointers in the +output vector (described with <b>pcre_exec()</b> below). To do the conversion, +you need to use the name-to-number map, which is described by these three +values. +</P> +<P> +The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives +the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each +entry; both of these return an <b>int</b> value. The entry size depends on the +length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first +entry of the table. This is a pointer to <b>char</b> in the 8-bit library, where +the first two bytes of each entry are the number of the capturing parenthesis, +most significant byte first. In the 16-bit library, the pointer points to +16-bit data units, the first of which contains the parenthesis number. In the +32-bit library, the pointer points to 32-bit data units, the first of which +contains the parenthesis number. The rest of the entry is the corresponding +name, zero terminated. +</P> +<P> +The names are in alphabetical order. If (?| is used to create multiple groups +with the same number, as described in the +<a href="pcrepattern.html#dupsubpatternnumber">section on duplicate subpattern numbers</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +page, the groups may be given the same name, but there is only one entry in the +table. Different names for groups of the same number are not permitted. +Duplicate names for subpatterns with different numbers are permitted, +but only if PCRE_DUPNAMES is set. They appear in the table in the order in +which they were found in the pattern. In the absence of (?| this is the order +of increasing number; when (?| is used this is not necessarily the case because +later subpatterns may have lower numbers. +</P> +<P> +As a simple example of the name/number table, consider the following pattern +after compilation by the 8-bit library (assume PCRE_EXTENDED is set, so white +space - including newlines - is ignored): +<pre> + (?<date> (?<year>(\d\d)?\d\d) - (?<month>\d\d) - (?<day>\d\d) ) +</pre> +There are four named subpatterns, so the table has four entries, and each entry +in the table is eight bytes long. The table is as follows, with non-printing +bytes shows in hexadecimal, and undefined bytes shown as ??: +<pre> + 00 01 d a t e 00 ?? + 00 05 d a y 00 ?? ?? + 00 04 m o n t h 00 + 00 02 y e a r 00 ?? +</pre> +When writing code to extract data from named subpatterns using the +name-to-number map, remember that the length of the entries is likely to be +different for each compiled pattern. +<pre> + PCRE_INFO_OKPARTIAL +</pre> +Return 1 if the pattern can be used for partial matching with +<b>pcre_exec()</b>, otherwise 0. The fourth argument should point to an +<b>int</b> variable. From release 8.00, this always returns 1, because the +restrictions that previously applied to partial matching have been lifted. The +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation gives details of partial matching. +<pre> + PCRE_INFO_OPTIONS +</pre> +Return a copy of the options with which the pattern was compiled. The fourth +argument should point to an <b>unsigned long int</b> variable. These option bits +are those specified in the call to <b>pcre_compile()</b>, modified by any +top-level option settings at the start of the pattern itself. In other words, +they are the options that will be in force when matching starts. For example, +if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the +result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED. +</P> +<P> +A pattern is automatically anchored by PCRE if all of its top-level +alternatives begin with one of the following: +<pre> + ^ unless PCRE_MULTILINE is set + \A always + \G always + .* if PCRE_DOTALL is set and there are no back references to the subpattern in which .* appears +</pre> +For such patterns, the PCRE_ANCHORED bit is set in the options returned by +<b>pcre_fullinfo()</b>. +<pre> + PCRE_INFO_RECURSIONLIMIT +</pre> +If the pattern set a recursion limit by including an item of the form +(*LIMIT_RECURSION=nnnn) at the start, the value is returned. The fourth +argument should point to an unsigned 32-bit integer. If no such value has been +set, the call to <b>pcre_fullinfo()</b> returns the error PCRE_ERROR_UNSET. +<pre> + PCRE_INFO_SIZE +</pre> +Return the size of the compiled pattern in bytes (for all three libraries). The +fourth argument should point to a <b>size_t</b> variable. This value does not +include the size of the <b>pcre</b> structure that is returned by +<b>pcre_compile()</b>. The value that is passed as the argument to +<b>pcre_malloc()</b> when <b>pcre_compile()</b> is getting memory in which to +place the compiled data is the value returned by this option plus the size of +the <b>pcre</b> structure. Studying a compiled pattern, with or without JIT, +does not alter the value returned by this option. +<pre> + PCRE_INFO_STUDYSIZE +</pre> +Return the size in bytes (for all three libraries) of the data block pointed to +by the <i>study_data</i> field in a <b>pcre_extra</b> block. If <b>pcre_extra</b> +is NULL, or there is no study data, zero is returned. The fourth argument +should point to a <b>size_t</b> variable. The <i>study_data</i> field is set by +<b>pcre_study()</b> to record information that will speed up matching (see the +section entitled +<a href="#studyingapattern">"Studying a pattern"</a> +above). The format of the <i>study_data</i> block is private, but its length +is made available via this option so that it can be saved and restored (see the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation for details). +<pre> + PCRE_INFO_REQUIREDCHARFLAGS +</pre> +Returns 1 if there is a rightmost literal data unit that must exist in any +matched string, other than at its start. The fourth argument should point to +an <b>int</b> variable. If there is no such value, 0 is returned. If returning +1, the character value itself can be retrieved using PCRE_INFO_REQUIREDCHAR. +</P> +<P> +For anchored patterns, a last literal value is recorded only if it follows +something of variable length. For example, for the pattern /^a\d+z\d+/ the +returned value 1 (with "z" returned from PCRE_INFO_REQUIREDCHAR), but for +/^a\dz\d/ the returned value is 0. +<pre> + PCRE_INFO_REQUIREDCHAR +</pre> +Return the value of the rightmost literal data unit that must exist in any +matched string, other than at its start, if such a value has been recorded. The +fourth argument should point to an <b>uint32_t</b> variable. If there is no such +value, 0 is returned. +</P> +<br><a name="SEC16" href="#TOC1">REFERENCE COUNTS</a><br> +<P> +<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b> +</P> +<P> +The <b>pcre_refcount()</b> function is used to maintain a reference count in the +data block that contains a compiled pattern. It is provided for the benefit of +applications that operate in an object-oriented manner, where different parts +of the application may be using the same compiled pattern, but you want to free +the block when they are all done. +</P> +<P> +When a pattern is compiled, the reference count field is initialized to zero. +It is changed only by calling this function, whose action is to add the +<i>adjust</i> value (which may be positive or negative) to it. The yield of the +function is the new value. However, the value of the count is constrained to +lie between 0 and 65535, inclusive. If the new value is outside these limits, +it is forced to the appropriate limit value. +</P> +<P> +Except when it is zero, the reference count is not correctly preserved if a +pattern is compiled on one host and then transferred to a host whose byte-order +is different. (This seems a highly unlikely scenario.) +</P> +<br><a name="SEC17" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a><br> +<P> +<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> +</P> +<P> +The function <b>pcre_exec()</b> is called to match a subject string against a +compiled pattern, which is passed in the <i>code</i> argument. If the +pattern was studied, the result of the study should be passed in the +<i>extra</i> argument. You can call <b>pcre_exec()</b> with the same <i>code</i> +and <i>extra</i> arguments as many times as you like, in order to match +different subject strings with the same pattern. +</P> +<P> +This function is the main matching facility of the library, and it operates in +a Perl-like manner. For specialist use there is also an alternative matching +function, which is described +<a href="#dfamatch">below</a> +in the section about the <b>pcre_dfa_exec()</b> function. +</P> +<P> +In most applications, the pattern will have been compiled (and optionally +studied) in the same process that calls <b>pcre_exec()</b>. However, it is +possible to save compiled patterns and study data, and then use them later +in different processes, possibly even on different hosts. For a discussion +about this, see the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation. +</P> +<P> +Here is an example of a simple call to <b>pcre_exec()</b>: +<pre> + int rc; + int ovector[30]; + rc = pcre_exec( + re, /* result of pcre_compile() */ + NULL, /* we didn't study the pattern */ + "some string", /* the subject string */ + 11, /* the length of the subject string */ + 0, /* start at offset 0 in the subject */ + 0, /* default options */ + ovector, /* vector of integers for substring information */ + 30); /* number of elements (NOT size in bytes) */ +<a name="extradata"></a></PRE> +</P> +<br><b> +Extra data for <b>pcre_exec()</b> +</b><br> +<P> +If the <i>extra</i> argument is not NULL, it must point to a <b>pcre_extra</b> +data block. The <b>pcre_study()</b> function returns such a block (when it +doesn't return NULL), but you can also create one for yourself, and pass +additional information in it. The <b>pcre_extra</b> block contains the following +fields (not necessarily in this order): +<pre> + unsigned long int <i>flags</i>; + void *<i>study_data</i>; + void *<i>executable_jit</i>; + unsigned long int <i>match_limit</i>; + unsigned long int <i>match_limit_recursion</i>; + void *<i>callout_data</i>; + const unsigned char *<i>tables</i>; + unsigned char **<i>mark</i>; +</pre> +In the 16-bit version of this structure, the <i>mark</i> field has type +"PCRE_UCHAR16 **". +<br> +<br> +In the 32-bit version of this structure, the <i>mark</i> field has type +"PCRE_UCHAR32 **". +</P> +<P> +The <i>flags</i> field is used to specify which of the other fields are set. The +flag bits are: +<pre> + PCRE_EXTRA_CALLOUT_DATA + PCRE_EXTRA_EXECUTABLE_JIT + PCRE_EXTRA_MARK + PCRE_EXTRA_MATCH_LIMIT + PCRE_EXTRA_MATCH_LIMIT_RECURSION + PCRE_EXTRA_STUDY_DATA + PCRE_EXTRA_TABLES +</pre> +Other flag bits should be set to zero. The <i>study_data</i> field and sometimes +the <i>executable_jit</i> field are set in the <b>pcre_extra</b> block that is +returned by <b>pcre_study()</b>, together with the appropriate flag bits. You +should not set these yourself, but you may add to the block by setting other +fields and their corresponding flag bits. +</P> +<P> +The <i>match_limit</i> field provides a means of preventing PCRE from using up a +vast amount of resources when running patterns that are not going to match, +but which have a very large number of possibilities in their search trees. The +classic example is a pattern that uses nested unlimited repeats. +</P> +<P> +Internally, <b>pcre_exec()</b> uses a function called <b>match()</b>, which it +calls repeatedly (sometimes recursively). The limit set by <i>match_limit</i> is +imposed on the number of times this function is called during a match, which +has the effect of limiting the amount of backtracking that can take place. For +patterns that are not anchored, the count restarts from zero for each position +in the subject string. +</P> +<P> +When <b>pcre_exec()</b> is called with a pattern that was successfully studied +with a JIT option, the way that the matching is executed is entirely different. +However, there is still the possibility of runaway matching that goes on for a +very long time, and so the <i>match_limit</i> value is also used in this case +(but in a different way) to limit how long the matching can continue. +</P> +<P> +The default value for the limit can be set when PCRE is built; the default +default is 10 million, which handles all but the most extreme cases. You can +override the default by suppling <b>pcre_exec()</b> with a <b>pcre_extra</b> +block in which <i>match_limit</i> is set, and PCRE_EXTRA_MATCH_LIMIT is set in +the <i>flags</i> field. If the limit is exceeded, <b>pcre_exec()</b> returns +PCRE_ERROR_MATCHLIMIT. +</P> +<P> +A value for the match limit may also be supplied by an item at the start of a +pattern of the form +<pre> + (*LIMIT_MATCH=d) +</pre> +where d is a decimal number. However, such a setting is ignored unless d is +less than the limit set by the caller of <b>pcre_exec()</b> or, if no such limit +is set, less than the default. +</P> +<P> +The <i>match_limit_recursion</i> field is similar to <i>match_limit</i>, but +instead of limiting the total number of times that <b>match()</b> is called, it +limits the depth of recursion. The recursion depth is a smaller number than the +total number of calls, because not all calls to <b>match()</b> are recursive. +This limit is of use only if it is set smaller than <i>match_limit</i>. +</P> +<P> +Limiting the recursion depth limits the amount of machine stack that can be +used, or, when PCRE has been compiled to use memory on the heap instead of the +stack, the amount of heap memory that can be used. This limit is not relevant, +and is ignored, when matching is done using JIT compiled code. +</P> +<P> +The default value for <i>match_limit_recursion</i> can be set when PCRE is +built; the default default is the same value as the default for +<i>match_limit</i>. You can override the default by suppling <b>pcre_exec()</b> +with a <b>pcre_extra</b> block in which <i>match_limit_recursion</i> is set, and +PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the <i>flags</i> field. If the limit +is exceeded, <b>pcre_exec()</b> returns PCRE_ERROR_RECURSIONLIMIT. +</P> +<P> +A value for the recursion limit may also be supplied by an item at the start of +a pattern of the form +<pre> + (*LIMIT_RECURSION=d) +</pre> +where d is a decimal number. However, such a setting is ignored unless d is +less than the limit set by the caller of <b>pcre_exec()</b> or, if no such limit +is set, less than the default. +</P> +<P> +The <i>callout_data</i> field is used in conjunction with the "callout" feature, +and is described in the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +</P> +<P> +The <i>tables</i> field is provided for use with patterns that have been +pre-compiled using custom character tables, saved to disc or elsewhere, and +then reloaded, because the tables that were used to compile a pattern are not +saved with it. See the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation for a discussion of saving compiled patterns for later use. If +NULL is passed using this mechanism, it forces PCRE's internal tables to be +used. +</P> +<P> +<b>Warning:</b> The tables that <b>pcre_exec()</b> uses must be the same as those +that were used when the pattern was compiled. If this is not the case, the +behaviour of <b>pcre_exec()</b> is undefined. Therefore, when a pattern is +compiled and matched in the same process, this field should never be set. In +this (the most common) case, the correct table pointer is automatically passed +with the compiled pattern from <b>pcre_compile()</b> to <b>pcre_exec()</b>. +</P> +<P> +If PCRE_EXTRA_MARK is set in the <i>flags</i> field, the <i>mark</i> field must +be set to point to a suitable variable. If the pattern contains any +backtracking control verbs such as (*MARK:NAME), and the execution ends up with +a name to pass back, a pointer to the name string (zero terminated) is placed +in the variable pointed to by the <i>mark</i> field. The names are within the +compiled pattern; if you wish to retain such a name you must copy it before +freeing the memory of a compiled pattern. If there is no name to pass back, the +variable pointed to by the <i>mark</i> field is set to NULL. For details of the +backtracking control verbs, see the section entitled +<a href="pcrepattern#backtrackcontrol">"Backtracking control"</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. +<a name="execoptions"></a></P> +<br><b> +Option bits for <b>pcre_exec()</b> +</b><br> +<P> +The unused bits of the <i>options</i> argument for <b>pcre_exec()</b> must be +zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>, +PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART, +PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and +PCRE_PARTIAL_SOFT. +</P> +<P> +If the pattern was successfully studied with one of the just-in-time (JIT) +compile options, the only supported options for JIT execution are +PCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, +PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an +unsupported option is used, JIT execution is disabled and the normal +interpretive code in <b>pcre_exec()</b> is run. +<pre> + PCRE_ANCHORED +</pre> +The PCRE_ANCHORED option limits <b>pcre_exec()</b> to matching at the first +matching position. If a pattern was compiled with PCRE_ANCHORED, or turned out +to be anchored by virtue of its contents, it cannot be made unachored at +matching time. +<pre> + PCRE_BSR_ANYCRLF + PCRE_BSR_UNICODE +</pre> +These options (which are mutually exclusive) control what the \R escape +sequence matches. The choice is either to match only CR, LF, or CRLF, or to +match any Unicode newline sequence. These options override the choice that was +made or defaulted when the pattern was compiled. +<pre> + PCRE_NEWLINE_CR + PCRE_NEWLINE_LF + PCRE_NEWLINE_CRLF + PCRE_NEWLINE_ANYCRLF + PCRE_NEWLINE_ANY +</pre> +These options override the newline definition that was chosen or defaulted when +the pattern was compiled. For details, see the description of +<b>pcre_compile()</b> above. During matching, the newline choice affects the +behaviour of the dot, circumflex, and dollar metacharacters. It may also alter +the way the match position is advanced after a match failure for an unanchored +pattern. +</P> +<P> +When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a +match attempt for an unanchored pattern fails when the current position is at a +CRLF sequence, and the pattern contains no explicit matches for CR or LF +characters, the match position is advanced by two characters instead of one, in +other words, to after the CRLF. +</P> +<P> +The above rule is a compromise that makes the most common cases work as +expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not +set), it does not match the string "\r\nA" because, after failing at the +start, it skips both the CR and the LF before retrying. However, the pattern +[\r\n]A does match that string, because it contains an explicit CR or LF +reference, and so advances only by one character after the first failure. +</P> +<P> +An explicit match for CR of LF is either a literal appearance of one of those +characters, or one of the \r or \n escape sequences. Implicit matches such as +[^X] do not count, nor does \s (which includes CR and LF in the characters +that it matches). +</P> +<P> +Notwithstanding the above, anomalous effects may still occur when CRLF is a +valid newline sequence and explicit \r or \n escapes appear in the pattern. +<pre> + PCRE_NOTBOL +</pre> +This option specifies that first character of the subject string is not the +beginning of a line, so the circumflex metacharacter should not match before +it. Setting this without PCRE_MULTILINE (at compile time) causes circumflex +never to match. This option affects only the behaviour of the circumflex +metacharacter. It does not affect \A. +<pre> + PCRE_NOTEOL +</pre> +This option specifies that the end of the subject string is not the end of a +line, so the dollar metacharacter should not match it nor (except in multiline +mode) a newline immediately before it. Setting this without PCRE_MULTILINE (at +compile time) causes dollar never to match. This option affects only the +behaviour of the dollar metacharacter. It does not affect \Z or \z. +<pre> + PCRE_NOTEMPTY +</pre> +An empty string is not considered to be a valid match if this option is set. If +there are alternatives in the pattern, they are tried. If all the alternatives +match the empty string, the entire match fails. For example, if the pattern +<pre> + a?b? +</pre> +is applied to a string not beginning with "a" or "b", it matches an empty +string at the start of the subject. With PCRE_NOTEMPTY set, this match is not +valid, so PCRE searches further into the string for occurrences of "a" or "b". +<pre> + PCRE_NOTEMPTY_ATSTART +</pre> +This is like PCRE_NOTEMPTY, except that an empty string match that is not at +the start of the subject is permitted. If the pattern is anchored, such a match +can occur only if the pattern contains \K. +</P> +<P> +Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it +does make a special case of a pattern match of the empty string within its +<b>split()</b> function, and when using the /g modifier. It is possible to +emulate Perl's behaviour after matching a null string by first trying the match +again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then +if that fails, by advancing the starting offset (see below) and trying an +ordinary match again. There is some code that demonstrates how to do this in +the +<a href="pcredemo.html"><b>pcredemo</b></a> +sample program. In the most general case, you have to check to see if the +newline convention recognizes CRLF as a newline, and if so, and the current +character is CR followed by LF, advance the starting offset by two characters +instead of one. +<pre> + PCRE_NO_START_OPTIMIZE +</pre> +There are a number of optimizations that <b>pcre_exec()</b> uses at the start of +a match, in order to speed up the process. For example, if it is known that an +unanchored match must start with a specific character, it searches the subject +for that character, and fails immediately if it cannot find it, without +actually running the main matching function. This means that a special item +such as (*COMMIT) at the start of a pattern is not considered until after a +suitable starting point for the match has been found. Also, when callouts or +(*MARK) items are in use, these "start-up" optimizations can cause them to be +skipped if the pattern is never actually used. The start-up optimizations are +in effect a pre-scan of the subject that takes place before the pattern is run. +</P> +<P> +The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly +causing performance to suffer, but ensuring that in cases where the result is +"no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK) +are considered at every possible starting position in the subject string. If +PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching +time. The use of PCRE_NO_START_OPTIMIZE at matching time (that is, passing it +to <b>pcre_exec()</b>) disables JIT execution; in this situation, matching is +always done using interpretively. +</P> +<P> +Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation. +Consider the pattern +<pre> + (*COMMIT)ABC +</pre> +When this is compiled, PCRE records the fact that a match must start with the +character "A". Suppose the subject string is "DEFABC". The start-up +optimization scans along the subject, finds "A" and runs the first match +attempt from there. The (*COMMIT) item means that the pattern must match the +current starting position, which in this case, it does. However, if the same +match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the +subject string does not happen. The first match attempt is run starting from +"D" and when this fails, (*COMMIT) prevents any further matches being tried, so +the overall result is "no match". If the pattern is studied, more start-up +optimizations may be used. For example, a minimum length for the subject may be +recorded. Consider the pattern +<pre> + (*MARK:A)(X|Y) +</pre> +The minimum length for a match is one character. If the subject is "ABC", there +will be attempts to match "ABC", "BC", "C", and then finally an empty string. +If the pattern is studied, the final attempt does not take place, because PCRE +knows that the subject is too short, and so the (*MARK) is never encountered. +In this case, studying the pattern does not affect the overall match result, +which is still "no match", but it does affect the auxiliary information that is +returned. +<pre> + PCRE_NO_UTF8_CHECK +</pre> +When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8 +string is automatically checked when <b>pcre_exec()</b> is subsequently called. +The entire string is checked before any other processing takes place. The value +of <i>startoffset</i> is also checked to ensure that it points to the start of a +UTF-8 character. There is a discussion about the +<a href="pcreunicode.html#utf8strings">validity of UTF-8 strings</a> +in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. If an invalid sequence of bytes is found, <b>pcre_exec()</b> returns the +error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a +truncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both +cases, information about the precise nature of the error may also be returned +(see the descriptions of these errors in the section entitled \fIError return +values from\fP <b>pcre_exec()</b> +<a href="#errorlist">below).</a> +If <i>startoffset</i> contains a value that does not point to the start of a +UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is +returned. +</P> +<P> +If you already know that your subject is valid, and you want to skip these +checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when +calling <b>pcre_exec()</b>. You might want to do this for the second and +subsequent calls to <b>pcre_exec()</b> if you are making repeated calls to find +all the matches in a single subject string. However, you should be sure that +the value of <i>startoffset</i> points to the start of a character (or the end +of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an +invalid string as a subject or an invalid value of <i>startoffset</i> is +undefined. Your program may crash or loop. +<pre> + PCRE_PARTIAL_HARD + PCRE_PARTIAL_SOFT +</pre> +These options turn on the partial matching feature. For backwards +compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match +occurs if the end of the subject string is reached successfully, but there are +not enough subject characters to complete the match. If this happens when +PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by +testing any remaining alternatives. Only if no complete match can be found is +PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words, +PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match, +but only if no complete match can be found. +</P> +<P> +If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a +partial match is found, <b>pcre_exec()</b> immediately returns +PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words, +when PCRE_PARTIAL_HARD is set, a partial match is considered to be more +important that an alternative complete match. +</P> +<P> +In both cases, the portion of the string that was inspected when the partial +match was found is set as the first matching string. There is a more detailed +discussion of partial and multi-segment matching, with examples, in the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation. +</P> +<br><b> +The string to be matched by <b>pcre_exec()</b> +</b><br> +<P> +The subject string is passed to <b>pcre_exec()</b> as a pointer in +<i>subject</i>, a length in <i>length</i>, and a starting offset in +<i>startoffset</i>. The units for <i>length</i> and <i>startoffset</i> are bytes +for the 8-bit library, 16-bit data items for the 16-bit library, and 32-bit +data items for the 32-bit library. +</P> +<P> +If <i>startoffset</i> is negative or greater than the length of the subject, +<b>pcre_exec()</b> returns PCRE_ERROR_BADOFFSET. When the starting offset is +zero, the search for a match starts at the beginning of the subject, and this +is by far the most common case. In UTF-8 or UTF-16 mode, the offset must point +to the start of a character, or the end of the subject (in UTF-32 mode, one +data unit equals one character, so all offsets are valid). Unlike the pattern +string, the subject may contain binary zeroes. +</P> +<P> +A non-zero starting offset is useful when searching for another match in the +same subject by calling <b>pcre_exec()</b> again after a previous success. +Setting <i>startoffset</i> differs from just passing over a shortened string and +setting PCRE_NOTBOL in the case of a pattern that begins with any kind of +lookbehind. For example, consider the pattern +<pre> + \Biss\B +</pre> +which finds occurrences of "iss" in the middle of words. (\B matches only if +the current position in the subject is not a word boundary.) When applied to +the string "Mississipi" the first call to <b>pcre_exec()</b> finds the first +occurrence. If <b>pcre_exec()</b> is called again with just the remainder of the +subject, namely "issipi", it does not match, because \B is always false at the +start of the subject, which is deemed to be a word boundary. However, if +<b>pcre_exec()</b> is passed the entire string again, but with <i>startoffset</i> +set to 4, it finds the second occurrence of "iss" because it is able to look +behind the starting point to discover that it is preceded by a letter. +</P> +<P> +Finding all the matches in a subject is tricky when the pattern can match an +empty string. It is possible to emulate Perl's /g behaviour by first trying the +match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and +PCRE_ANCHORED options, and then if that fails, advancing the starting offset +and trying an ordinary match again. There is some code that demonstrates how to +do this in the +<a href="pcredemo.html"><b>pcredemo</b></a> +sample program. In the most general case, you have to check to see if the +newline convention recognizes CRLF as a newline, and if so, and the current +character is CR followed by LF, advance the starting offset by two characters +instead of one. +</P> +<P> +If a non-zero starting offset is passed when the pattern is anchored, one +attempt to match at the given offset is made. This can only succeed if the +pattern does not require the match to be at the start of the subject. +</P> +<br><b> +How <b>pcre_exec()</b> returns captured substrings +</b><br> +<P> +In general, a pattern matches a certain portion of the subject, and in +addition, further substrings from the subject may be picked out by parts of the +pattern. Following the usage in Jeffrey Friedl's book, this is called +"capturing" in what follows, and the phrase "capturing subpattern" is used for +a fragment of a pattern that picks out a substring. PCRE supports several other +kinds of parenthesized subpattern that do not cause substrings to be captured. +</P> +<P> +Captured substrings are returned to the caller via a vector of integers whose +address is passed in <i>ovector</i>. The number of elements in the vector is +passed in <i>ovecsize</i>, which must be a non-negative number. <b>Note</b>: this +argument is NOT the size of <i>ovector</i> in bytes. +</P> +<P> +The first two-thirds of the vector is used to pass back captured substrings, +each substring using a pair of integers. The remaining third of the vector is +used as workspace by <b>pcre_exec()</b> while matching capturing subpatterns, +and is not available for passing back information. The number passed in +<i>ovecsize</i> should always be a multiple of three. If it is not, it is +rounded down. +</P> +<P> +When a match is successful, information about captured substrings is returned +in pairs of integers, starting at the beginning of <i>ovector</i>, and +continuing up to two-thirds of its length at the most. The first element of +each pair is set to the offset of the first character in a substring, and the +second is set to the offset of the first character after the end of a +substring. These values are always data unit offsets, even in UTF mode. They +are byte offsets in the 8-bit library, 16-bit data item offsets in the 16-bit +library, and 32-bit data item offsets in the 32-bit library. <b>Note</b>: they +are not character counts. +</P> +<P> +The first pair of integers, <i>ovector[0]</i> and <i>ovector[1]</i>, identify the +portion of the subject string matched by the entire pattern. The next pair is +used for the first capturing subpattern, and so on. The value returned by +<b>pcre_exec()</b> is one more than the highest numbered pair that has been set. +For example, if two substrings have been captured, the returned value is 3. If +there are no capturing subpatterns, the return value from a successful match is +1, indicating that just the first pair of offsets has been set. +</P> +<P> +If a capturing subpattern is matched repeatedly, it is the last portion of the +string that it matched that is returned. +</P> +<P> +If the vector is too small to hold all the captured substring offsets, it is +used as far as possible (up to two-thirds of its length), and the function +returns a value of zero. If neither the actual string matched nor any captured +substrings are of interest, <b>pcre_exec()</b> may be called with <i>ovector</i> +passed as NULL and <i>ovecsize</i> as zero. However, if the pattern contains +back references and the <i>ovector</i> is not big enough to remember the related +substrings, PCRE has to get additional memory for use during matching. Thus it +is usually advisable to supply an <i>ovector</i> of reasonable size. +</P> +<P> +There are some cases where zero is returned (indicating vector overflow) when +in fact the vector is exactly the right size for the final match. For example, +consider the pattern +<pre> + (a)(?:(b)c|bd) +</pre> +If a vector of 6 elements (allowing for only 1 captured substring) is given +with subject string "abd", <b>pcre_exec()</b> will try to set the second +captured string, thereby recording a vector overflow, before failing to match +"c" and backing up to try the second alternative. The zero return, however, +does correctly indicate that the maximum number of slots (namely 2) have been +filled. In similar cases where there is temporary overflow, but the final +number of used slots is actually less than the maximum, a non-zero value is +returned. +</P> +<P> +The <b>pcre_fullinfo()</b> function can be used to find out how many capturing +subpatterns there are in a compiled pattern. The smallest size for +<i>ovector</i> that will allow for <i>n</i> captured substrings, in addition to +the offsets of the substring matched by the whole pattern, is (<i>n</i>+1)*3. +</P> +<P> +It is possible for capturing subpattern number <i>n+1</i> to match some part of +the subject when subpattern <i>n</i> has not been used at all. For example, if +the string "abc" is matched against the pattern (a|(z))(bc) the return from the +function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this +happens, both values in the offset pairs corresponding to unused subpatterns +are set to -1. +</P> +<P> +Offset values that correspond to unused subpatterns at the end of the +expression are also set to -1. For example, if the string "abc" is matched +against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The +return from the function is 2, because the highest used capturing subpattern +number is 1, and the offsets for for the second and third capturing subpatterns +(assuming the vector is large enough, of course) are set to -1. +</P> +<P> +<b>Note</b>: Elements in the first two-thirds of <i>ovector</i> that do not +correspond to capturing parentheses in the pattern are never changed. That is, +if a pattern contains <i>n</i> capturing parentheses, no more than +<i>ovector[0]</i> to <i>ovector[2n+1]</i> are set by <b>pcre_exec()</b>. The other +elements (in the first two-thirds) retain whatever values they previously had. +</P> +<P> +Some convenience functions are provided for extracting the captured substrings +as separate strings. These are described below. +<a name="errorlist"></a></P> +<br><b> +Error return values from <b>pcre_exec()</b> +</b><br> +<P> +If <b>pcre_exec()</b> fails, it returns a negative number. The following are +defined in the header file: +<pre> + PCRE_ERROR_NOMATCH (-1) +</pre> +The subject string did not match the pattern. +<pre> + PCRE_ERROR_NULL (-2) +</pre> +Either <i>code</i> or <i>subject</i> was passed as NULL, or <i>ovector</i> was +NULL and <i>ovecsize</i> was not zero. +<pre> + PCRE_ERROR_BADOPTION (-3) +</pre> +An unrecognized bit was set in the <i>options</i> argument. +<pre> + PCRE_ERROR_BADMAGIC (-4) +</pre> +PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch +the case when it is passed a junk pointer and to detect when a pattern that was +compiled in an environment of one endianness is run in an environment with the +other endianness. This is the error that PCRE gives when the magic number is +not present. +<pre> + PCRE_ERROR_UNKNOWN_OPCODE (-5) +</pre> +While running the pattern match, an unknown item was encountered in the +compiled pattern. This error could be caused by a bug in PCRE or by overwriting +of the compiled pattern. +<pre> + PCRE_ERROR_NOMEMORY (-6) +</pre> +If a pattern contains back references, but the <i>ovector</i> that is passed to +<b>pcre_exec()</b> is not big enough to remember the referenced substrings, PCRE +gets a block of memory at the start of matching to use for this purpose. If the +call via <b>pcre_malloc()</b> fails, this error is given. The memory is +automatically freed at the end of matching. +</P> +<P> +This error is also given if <b>pcre_stack_malloc()</b> fails in +<b>pcre_exec()</b>. This can happen only when PCRE has been compiled with +<b>--disable-stack-for-recursion</b>. +<pre> + PCRE_ERROR_NOSUBSTRING (-7) +</pre> +This error is used by the <b>pcre_copy_substring()</b>, +<b>pcre_get_substring()</b>, and <b>pcre_get_substring_list()</b> functions (see +below). It is never returned by <b>pcre_exec()</b>. +<pre> + PCRE_ERROR_MATCHLIMIT (-8) +</pre> +The backtracking limit, as specified by the <i>match_limit</i> field in a +<b>pcre_extra</b> structure (or defaulted) was reached. See the description +above. +<pre> + PCRE_ERROR_CALLOUT (-9) +</pre> +This error is never generated by <b>pcre_exec()</b> itself. It is provided for +use by callout functions that want to yield a distinctive error code. See the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation for details. +<pre> + PCRE_ERROR_BADUTF8 (-10) +</pre> +A string that contains an invalid UTF-8 byte sequence was passed as a subject, +and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector +(<i>ovecsize</i>) is at least 2, the byte offset to the start of the the invalid +UTF-8 character is placed in the first element, and a reason code is placed in +the second element. The reason codes are listed in the +<a href="#badutf8reasons">following section.</a> +For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a +truncated UTF-8 character at the end of the subject (reason codes 1 to 5), +PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8. +<pre> + PCRE_ERROR_BADUTF8_OFFSET (-11) +</pre> +The UTF-8 byte sequence that was passed as a subject was checked and found to +be valid (the PCRE_NO_UTF8_CHECK option was not set), but the value of +<i>startoffset</i> did not point to the beginning of a UTF-8 character or the +end of the subject. +<pre> + PCRE_ERROR_PARTIAL (-12) +</pre> +The subject string did not match, but it did match partially. See the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation for details of partial matching. +<pre> + PCRE_ERROR_BADPARTIAL (-13) +</pre> +This code is no longer in use. It was formerly returned when the PCRE_PARTIAL +option was used with a compiled pattern containing items that were not +supported for partial matching. From release 8.00 onwards, there are no +restrictions on partial matching. +<pre> + PCRE_ERROR_INTERNAL (-14) +</pre> +An unexpected internal error has occurred. This error could be caused by a bug +in PCRE or by overwriting of the compiled pattern. +<pre> + PCRE_ERROR_BADCOUNT (-15) +</pre> +This error is given if the value of the <i>ovecsize</i> argument is negative. +<pre> + PCRE_ERROR_RECURSIONLIMIT (-21) +</pre> +The internal recursion limit, as specified by the <i>match_limit_recursion</i> +field in a <b>pcre_extra</b> structure (or defaulted) was reached. See the +description above. +<pre> + PCRE_ERROR_BADNEWLINE (-23) +</pre> +An invalid combination of PCRE_NEWLINE_<i>xxx</i> options was given. +<pre> + PCRE_ERROR_BADOFFSET (-24) +</pre> +The value of <i>startoffset</i> was negative or greater than the length of the +subject, that is, the value in <i>length</i>. +<pre> + PCRE_ERROR_SHORTUTF8 (-25) +</pre> +This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string +ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set. +Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in +fact sufficient to detect this case, but this special error code for +PCRE_PARTIAL_HARD precedes the implementation of returned information; it is +retained for backwards compatibility. +<pre> + PCRE_ERROR_RECURSELOOP (-26) +</pre> +This error is returned when <b>pcre_exec()</b> detects a recursion loop within +the pattern. Specifically, it means that either the whole pattern or a +subpattern has been called recursively for the second time at the same position +in the subject string. Some simple patterns that might do this are detected and +faulted at compile time, but more complicated cases, in particular mutual +recursions between two different subpatterns, cannot be detected until run +time. +<pre> + PCRE_ERROR_JIT_STACKLIMIT (-27) +</pre> +This error is returned when a pattern that was successfully studied using a +JIT compile option is being matched, but the memory available for the +just-in-time processing stack is not large enough. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for more details. +<pre> + PCRE_ERROR_BADMODE (-28) +</pre> +This error is given if a pattern that was compiled by the 8-bit library is +passed to a 16-bit or 32-bit library function, or vice versa. +<pre> + PCRE_ERROR_BADENDIANNESS (-29) +</pre> +This error is given if a pattern that was compiled and saved is reloaded on a +host with different endianness. The utility function +<b>pcre_pattern_to_host_byte_order()</b> can be used to convert such a pattern +so that it runs on the new host. +<pre> + PCRE_ERROR_JIT_BADOPTION +</pre> +This error is returned when a pattern that was successfully studied using a JIT +compile option is being matched, but the matching mode (partial or complete +match) does not correspond to any JIT compilation mode. When the JIT fast path +function is used, this error may be also given for invalid options. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for more details. +<pre> + PCRE_ERROR_BADLENGTH (-32) +</pre> +This error is given if <b>pcre_exec()</b> is called with a negative value for +the <i>length</i> argument. +</P> +<P> +Error numbers -16 to -20, -22, and 30 are not used by <b>pcre_exec()</b>. +<a name="badutf8reasons"></a></P> +<br><b> +Reason codes for invalid UTF-8 strings +</b><br> +<P> +This section applies only to the 8-bit library. The corresponding information +for the 16-bit and 32-bit libraries is given in the +<a href="pcre16.html"><b>pcre16</b></a> +and +<a href="pcre32.html"><b>pcre32</b></a> +pages. +</P> +<P> +When <b>pcre_exec()</b> returns either PCRE_ERROR_BADUTF8 or +PCRE_ERROR_SHORTUTF8, and the size of the output vector (<i>ovecsize</i>) is at +least 2, the offset of the start of the invalid UTF-8 character is placed in +the first output vector element (<i>ovector[0]</i>) and a reason code is placed +in the second element (<i>ovector[1]</i>). The reason codes are given names in +the <b>pcre.h</b> header file: +<pre> + PCRE_UTF8_ERR1 + PCRE_UTF8_ERR2 + PCRE_UTF8_ERR3 + PCRE_UTF8_ERR4 + PCRE_UTF8_ERR5 +</pre> +The string ends with a truncated UTF-8 character; the code specifies how many +bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be +no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279) +allows for up to 6 bytes, and this is checked first; hence the possibility of +4 or 5 missing bytes. +<pre> + PCRE_UTF8_ERR6 + PCRE_UTF8_ERR7 + PCRE_UTF8_ERR8 + PCRE_UTF8_ERR9 + PCRE_UTF8_ERR10 +</pre> +The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the +character do not have the binary value 0b10 (that is, either the most +significant bit is 0, or the next bit is 1). +<pre> + PCRE_UTF8_ERR11 + PCRE_UTF8_ERR12 +</pre> +A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long; +these code points are excluded by RFC 3629. +<pre> + PCRE_UTF8_ERR13 +</pre> +A 4-byte character has a value greater than 0x10fff; these code points are +excluded by RFC 3629. +<pre> + PCRE_UTF8_ERR14 +</pre> +A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of +code points are reserved by RFC 3629 for use with UTF-16, and so are excluded +from UTF-8. +<pre> + PCRE_UTF8_ERR15 + PCRE_UTF8_ERR16 + PCRE_UTF8_ERR17 + PCRE_UTF8_ERR18 + PCRE_UTF8_ERR19 +</pre> +A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a +value that can be represented by fewer bytes, which is invalid. For example, +the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just +one byte. +<pre> + PCRE_UTF8_ERR20 +</pre> +The two most significant bits of the first byte of a character have the binary +value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a +byte can only validly occur as the second or subsequent byte of a multi-byte +character. +<pre> + PCRE_UTF8_ERR21 +</pre> +The first byte of a character has the value 0xfe or 0xff. These values can +never occur in a valid UTF-8 string. +<pre> + PCRE_UTF8_ERR22 +</pre> +This error code was formerly used when the presence of a so-called +"non-character" caused an error. Unicode corrigendum #9 makes it clear that +such characters should not cause a string to be rejected, and so this code is +no longer in use and is never returned. +</P> +<br><a name="SEC18" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br> +<P> +<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> +<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> +<b> int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> +</P> +<P> +Captured substrings can be accessed directly by using the offsets returned by +<b>pcre_exec()</b> in <i>ovector</i>. For convenience, the functions +<b>pcre_copy_substring()</b>, <b>pcre_get_substring()</b>, and +<b>pcre_get_substring_list()</b> are provided for extracting captured substrings +as new, separate, zero-terminated strings. These functions identify substrings +by number. The next section describes functions for extracting named +substrings. +</P> +<P> +A substring that contains a binary zero is correctly extracted and has a +further zero added on the end, but the result is not, of course, a C string. +However, you can process such a string by referring to the length that is +returned by <b>pcre_copy_substring()</b> and <b>pcre_get_substring()</b>. +Unfortunately, the interface to <b>pcre_get_substring_list()</b> is not adequate +for handling strings containing binary zeros, because the end of the final +string is not independently indicated. +</P> +<P> +The first three arguments are the same for all three of these functions: +<i>subject</i> is the subject string that has just been successfully matched, +<i>ovector</i> is a pointer to the vector of integer offsets that was passed to +<b>pcre_exec()</b>, and <i>stringcount</i> is the number of substrings that were +captured by the match, including the substring that matched the entire regular +expression. This is the value returned by <b>pcre_exec()</b> if it is greater +than zero. If <b>pcre_exec()</b> returned zero, indicating that it ran out of +space in <i>ovector</i>, the value passed as <i>stringcount</i> should be the +number of elements in the vector divided by three. +</P> +<P> +The functions <b>pcre_copy_substring()</b> and <b>pcre_get_substring()</b> +extract a single substring, whose number is given as <i>stringnumber</i>. A +value of zero extracts the substring that matched the entire pattern, whereas +higher values extract the captured substrings. For <b>pcre_copy_substring()</b>, +the string is placed in <i>buffer</i>, whose length is given by +<i>buffersize</i>, while for <b>pcre_get_substring()</b> a new block of memory is +obtained via <b>pcre_malloc</b>, and its address is returned via +<i>stringptr</i>. The yield of the function is the length of the string, not +including the terminating zero, or one of these error codes: +<pre> + PCRE_ERROR_NOMEMORY (-6) +</pre> +The buffer was too small for <b>pcre_copy_substring()</b>, or the attempt to get +memory failed for <b>pcre_get_substring()</b>. +<pre> + PCRE_ERROR_NOSUBSTRING (-7) +</pre> +There is no substring whose number is <i>stringnumber</i>. +</P> +<P> +The <b>pcre_get_substring_list()</b> function extracts all available substrings +and builds a list of pointers to them. All this is done in a single block of +memory that is obtained via <b>pcre_malloc</b>. The address of the memory block +is returned via <i>listptr</i>, which is also the start of the list of string +pointers. The end of the list is marked by a NULL pointer. The yield of the +function is zero if all went well, or the error code +<pre> + PCRE_ERROR_NOMEMORY (-6) +</pre> +if the attempt to get the memory block failed. +</P> +<P> +When any of these functions encounter a substring that is unset, which can +happen when capturing subpattern number <i>n+1</i> matches some part of the +subject, but subpattern <i>n</i> has not been used at all, they return an empty +string. This can be distinguished from a genuine zero-length substring by +inspecting the appropriate offset in <i>ovector</i>, which is negative for unset +substrings. +</P> +<P> +The two convenience functions <b>pcre_free_substring()</b> and +<b>pcre_free_substring_list()</b> can be used to free the memory returned by +a previous call of <b>pcre_get_substring()</b> or +<b>pcre_get_substring_list()</b>, respectively. They do nothing more than call +the function pointed to by <b>pcre_free</b>, which of course could be called +directly from a C program. However, PCRE is used in some situations where it is +linked via a special interface to another programming language that cannot use +<b>pcre_free</b> directly; it is for these cases that the functions are +provided. +</P> +<br><a name="SEC19" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br> +<P> +<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>);</b> +<br> +<br> +<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> char *<i>buffer</i>, int <i>buffersize</i>);</b> +<br> +<br> +<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> +<b> const char *<i>subject</i>, int *<i>ovector</i>,</b> +<b> int <i>stringcount</i>, const char *<i>stringname</i>,</b> +<b> const char **<i>stringptr</i>);</b> +</P> +<P> +To extract a substring by name, you first have to find associated number. +For example, for this pattern +<pre> + (a+)b(?<xxx>\d+)... +</pre> +the number of the subpattern called "xxx" is 2. If the name is known to be +unique (PCRE_DUPNAMES was not set), you can find the number from the name by +calling <b>pcre_get_stringnumber()</b>. The first argument is the compiled +pattern, and the second is the name. The yield of the function is the +subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of +that name. +</P> +<P> +Given the number, you can extract the substring directly, or use one of the +functions described in the previous section. For convenience, there are also +two functions that do the whole job. +</P> +<P> +Most of the arguments of <b>pcre_copy_named_substring()</b> and +<b>pcre_get_named_substring()</b> are the same as those for the similarly named +functions that extract by number. As these are described in the previous +section, they are not re-described here. There are just two differences: +</P> +<P> +First, instead of a substring number, a substring name is given. Second, there +is an extra argument, given at the start, which is a pointer to the compiled +pattern. This is needed in order to gain access to the name-to-number +translation table. +</P> +<P> +These functions call <b>pcre_get_stringnumber()</b>, and if it succeeds, they +then call <b>pcre_copy_substring()</b> or <b>pcre_get_substring()</b>, as +appropriate. <b>NOTE:</b> If PCRE_DUPNAMES is set and there are duplicate names, +the behaviour may not be what you want (see the next section). +</P> +<P> +<b>Warning:</b> If the pattern uses the (?| feature to set up multiple +subpatterns with the same number, as described in the +<a href="pcrepattern.html#dupsubpatternnumber">section on duplicate subpattern numbers</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +page, you cannot use names to distinguish the different subpatterns, because +names are not included in the compiled code. The matching process uses only +numbers. For this reason, the use of different names for subpatterns of the +same number causes an error at compile time. +</P> +<br><a name="SEC20" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br> +<P> +<b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b> +<b> const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> +</P> +<P> +When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns +are not required to be unique. (Duplicate names are always allowed for +subpatterns with the same number, created by using the (?| feature. Indeed, if +such subpatterns are named, they are required to use the same names.) +</P> +<P> +Normally, patterns with duplicate names are such that in any one match, only +one of the named subpatterns participates. An example is shown in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. +</P> +<P> +When duplicates are present, <b>pcre_copy_named_substring()</b> and +<b>pcre_get_named_substring()</b> return the first substring corresponding to +the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is +returned; no data is returned. The <b>pcre_get_stringnumber()</b> function +returns one of the numbers that are associated with the name, but it is not +defined which it is. +</P> +<P> +If you want to get full details of all captured substrings for a given name, +you must use the <b>pcre_get_stringtable_entries()</b> function. The first +argument is the compiled pattern, and the second is the name. The third and +fourth are pointers to variables which are updated by the function. After it +has run, they point to the first and last entries in the name-to-number table +for the given name. The function itself returns the length of each entry, or +PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is +described above in the section entitled <i>Information about a pattern</i> +<a href="#infoaboutpattern">above.</a> +Given all the relevant entries for the name, you can extract each of their +numbers, and hence the captured data, if any. +</P> +<br><a name="SEC21" href="#TOC1">FINDING ALL POSSIBLE MATCHES</a><br> +<P> +The traditional matching function uses a similar algorithm to Perl, which stops +when it finds the first match, starting at a given point in the subject. If you +want to find all possible matches, or the longest possible match, consider +using the alternative matching function (see below) instead. If you cannot use +the alternative function, but still need to find all possible matches, you +can kludge it up by making use of the callout facility, which is described in +the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +</P> +<P> +What you have to do is to insert a callout right at the end of the pattern. +When your callout function is called, extract and save the current matched +substring. Then return 1, which forces <b>pcre_exec()</b> to backtrack and try +other alternatives. Ultimately, when it runs out of matches, <b>pcre_exec()</b> +will yield PCRE_ERROR_NOMATCH. +</P> +<br><a name="SEC22" href="#TOC1">OBTAINING AN ESTIMATE OF STACK USAGE</a><br> +<P> +Matching certain patterns using <b>pcre_exec()</b> can use a lot of process +stack, which in certain environments can be rather limited in size. Some users +find it helpful to have an estimate of the amount of stack that is used by +<b>pcre_exec()</b>, to help them set recursion limits, as described in the +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation. The estimate that is output by <b>pcretest</b> when called with +the <b>-m</b> and <b>-C</b> options is obtained by calling <b>pcre_exec</b> with +the values NULL, NULL, NULL, -999, and -999 for its first five arguments. +</P> +<P> +Normally, if its first argument is NULL, <b>pcre_exec()</b> immediately returns +the negative error code PCRE_ERROR_NULL, but with this special combination of +arguments, it returns instead a negative number whose absolute value is the +approximate stack frame size in bytes. (A negative number is used so that it is +clear that no match has happened.) The value is approximate because in some +cases, recursive calls to <b>pcre_exec()</b> occur when there are one or two +additional variables on the stack. +</P> +<P> +If PCRE has been compiled to use the heap instead of the stack for recursion, +the value returned is the size of each block that is obtained from the heap. +<a name="dfamatch"></a></P> +<br><a name="SEC23" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br> +<P> +<b>int pcre_dfa_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> +<b> const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> +<b> int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> +</P> +<P> +The function <b>pcre_dfa_exec()</b> is called to match a subject string against +a compiled pattern, using a matching algorithm that scans the subject string +just once, and does not backtrack. This has different characteristics to the +normal algorithm, and is not compatible with Perl. Some of the features of PCRE +patterns are not supported. Nevertheless, there are times when this kind of +matching can be useful. For a discussion of the two matching algorithms, and a +list of features that <b>pcre_dfa_exec()</b> does not support, see the +<a href="pcrematching.html"><b>pcrematching</b></a> +documentation. +</P> +<P> +The arguments for the <b>pcre_dfa_exec()</b> function are the same as for +<b>pcre_exec()</b>, plus two extras. The <i>ovector</i> argument is used in a +different way, and this is described below. The other common arguments are used +in the same way as for <b>pcre_exec()</b>, so their description is not repeated +here. +</P> +<P> +The two additional arguments provide workspace for the function. The workspace +vector should contain at least 20 elements. It is used for keeping track of +multiple paths through the pattern tree. More workspace will be needed for +patterns and subjects where there are a lot of potential matches. +</P> +<P> +Here is an example of a simple call to <b>pcre_dfa_exec()</b>: +<pre> + int rc; + int ovector[10]; + int wspace[20]; + rc = pcre_dfa_exec( + re, /* result of pcre_compile() */ + NULL, /* we didn't study the pattern */ + "some string", /* the subject string */ + 11, /* the length of the subject string */ + 0, /* start at offset 0 in the subject */ + 0, /* default options */ + ovector, /* vector of integers for substring information */ + 10, /* number of elements (NOT size in bytes) */ + wspace, /* working space vector */ + 20); /* number of elements (NOT size in bytes) */ +</PRE> +</P> +<br><b> +Option bits for <b>pcre_dfa_exec()</b> +</b><br> +<P> +The unused bits of the <i>options</i> argument for <b>pcre_dfa_exec()</b> must be +zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>, +PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART, +PCRE_NO_UTF8_CHECK, PCRE_BSR_ANYCRLF, PCRE_BSR_UNICODE, PCRE_NO_START_OPTIMIZE, +PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. +All but the last four of these are exactly the same as for <b>pcre_exec()</b>, +so their description is not repeated here. +<pre> + PCRE_PARTIAL_HARD + PCRE_PARTIAL_SOFT +</pre> +These have the same general effect as they do for <b>pcre_exec()</b>, but the +details are slightly different. When PCRE_PARTIAL_HARD is set for +<b>pcre_dfa_exec()</b>, it returns PCRE_ERROR_PARTIAL if the end of the subject +is reached and there is still at least one matching possibility that requires +additional characters. This happens even if some complete matches have also +been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH +is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached, +there have been no complete matches, but there is still at least one matching +possibility. The portion of the string that was inspected when the longest +partial match was found is set as the first matching string in both cases. +There is a more detailed discussion of partial and multi-segment matching, with +examples, in the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation. +<pre> + PCRE_DFA_SHORTEST +</pre> +Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as +soon as it has found one match. Because of the way the alternative algorithm +works, this is necessarily the shortest possible match at the first possible +matching point in the subject string. +<pre> + PCRE_DFA_RESTART +</pre> +When <b>pcre_dfa_exec()</b> returns a partial match, it is possible to call it +again, with additional subject characters, and have it continue with the same +match. The PCRE_DFA_RESTART option requests this action; when it is set, the +<i>workspace</i> and <i>wscount</i> options must reference the same vector as +before because data about the match so far is left in them after a partial +match. There is more discussion of this facility in the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation. +</P> +<br><b> +Successful returns from <b>pcre_dfa_exec()</b> +</b><br> +<P> +When <b>pcre_dfa_exec()</b> succeeds, it may have matched more than one +substring in the subject. Note, however, that all the matches from one run of +the function start at the same point in the subject. The shorter matches are +all initial substrings of the longer matches. For example, if the pattern +<pre> + <.*> +</pre> +is matched against the string +<pre> + This is <something> <something else> <something further> no more +</pre> +the three matched strings are +<pre> + <something> + <something> <something else> + <something> <something else> <something further> +</pre> +On success, the yield of the function is a number greater than zero, which is +the number of matched substrings. The substrings themselves are returned in +<i>ovector</i>. Each string uses two elements; the first is the offset to the +start, and the second is the offset to the end. In fact, all the strings have +the same start offset. (Space could have been saved by giving this only once, +but it was decided to retain some compatibility with the way <b>pcre_exec()</b> +returns data, even though the meaning of the strings is different.) +</P> +<P> +The strings are returned in reverse order of length; that is, the longest +matching string is given first. If there were too many matches to fit into +<i>ovector</i>, the yield of the function is zero, and the vector is filled with +the longest matches. Unlike <b>pcre_exec()</b>, <b>pcre_dfa_exec()</b> can use +the entire <i>ovector</i> for returning matched strings. +</P> +<P> +NOTE: PCRE's "auto-possessification" optimization usually applies to character +repeats at the end of a pattern (as well as internally). For example, the +pattern "a\d+" is compiled as if it were "a\d++" because there is no point +even considering the possibility of backtracking into the repeated digits. For +DFA matching, this means that only one possible match is found. If you really +do want multiple matches in such cases, either use an ungreedy repeat +("a\d+?") or set the PCRE_NO_AUTO_POSSESS option when compiling. +</P> +<br><b> +Error returns from <b>pcre_dfa_exec()</b> +</b><br> +<P> +The <b>pcre_dfa_exec()</b> function returns a negative number when it fails. +Many of the errors are the same as for <b>pcre_exec()</b>, and these are +described +<a href="#errorlist">above.</a> +There are in addition the following errors that are specific to +<b>pcre_dfa_exec()</b>: +<pre> + PCRE_ERROR_DFA_UITEM (-16) +</pre> +This return is given if <b>pcre_dfa_exec()</b> encounters an item in the pattern +that it does not support, for instance, the use of \C or a back reference. +<pre> + PCRE_ERROR_DFA_UCOND (-17) +</pre> +This return is given if <b>pcre_dfa_exec()</b> encounters a condition item that +uses a back reference for the condition, or a test for recursion in a specific +group. These are not supported. +<pre> + PCRE_ERROR_DFA_UMLIMIT (-18) +</pre> +This return is given if <b>pcre_dfa_exec()</b> is called with an <i>extra</i> +block that contains a setting of the <i>match_limit</i> or +<i>match_limit_recursion</i> fields. This is not supported (these fields are +meaningless for DFA matching). +<pre> + PCRE_ERROR_DFA_WSSIZE (-19) +</pre> +This return is given if <b>pcre_dfa_exec()</b> runs out of space in the +<i>workspace</i> vector. +<pre> + PCRE_ERROR_DFA_RECURSE (-20) +</pre> +When a recursive subpattern is processed, the matching function calls itself +recursively, using private vectors for <i>ovector</i> and <i>workspace</i>. This +error is given if the output vector is not large enough. This should be +extremely rare, as a vector of size 1000 is used. +<pre> + PCRE_ERROR_DFA_BADRESTART (-30) +</pre> +When <b>pcre_dfa_exec()</b> is called with the <b>PCRE_DFA_RESTART</b> option, +some plausibility checks are made on the contents of the workspace, which +should contain data about the previous partial match. If any of these checks +fail, this error is given. +</P> +<br><a name="SEC24" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcre16</b>(3), <b>pcre32</b>(3), <b>pcrebuild</b>(3), <b>pcrecallout</b>(3), +<b>pcrecpp(3)</b>(3), <b>pcrematching</b>(3), <b>pcrepartial</b>(3), +<b>pcreposix</b>(3), <b>pcreprecompile</b>(3), <b>pcresample</b>(3), +<b>pcrestack</b>(3). +</P> +<br><a name="SEC25" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC26" href="#TOC1">REVISION</a><br> +<P> +Last updated: 09 February 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrebuild.html b/doc/html/pcrebuild.html new file mode 100644 index 0000000..03c8cbe --- /dev/null +++ b/doc/html/pcrebuild.html @@ -0,0 +1,534 @@ +<html> +<head> +<title>pcrebuild specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrebuild man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">BUILDING PCRE</a> +<li><a name="TOC2" href="#SEC2">PCRE BUILD-TIME OPTIONS</a> +<li><a name="TOC3" href="#SEC3">BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a> +<li><a name="TOC4" href="#SEC4">BUILDING SHARED AND STATIC LIBRARIES</a> +<li><a name="TOC5" href="#SEC5">C++ SUPPORT</a> +<li><a name="TOC6" href="#SEC6">UTF-8, UTF-16 AND UTF-32 SUPPORT</a> +<li><a name="TOC7" href="#SEC7">UNICODE CHARACTER PROPERTY SUPPORT</a> +<li><a name="TOC8" href="#SEC8">JUST-IN-TIME COMPILER SUPPORT</a> +<li><a name="TOC9" href="#SEC9">CODE VALUE OF NEWLINE</a> +<li><a name="TOC10" href="#SEC10">WHAT \R MATCHES</a> +<li><a name="TOC11" href="#SEC11">POSIX MALLOC USAGE</a> +<li><a name="TOC12" href="#SEC12">HANDLING VERY LARGE PATTERNS</a> +<li><a name="TOC13" href="#SEC13">AVOIDING EXCESSIVE STACK USAGE</a> +<li><a name="TOC14" href="#SEC14">LIMITING PCRE RESOURCE USAGE</a> +<li><a name="TOC15" href="#SEC15">CREATING CHARACTER TABLES AT BUILD TIME</a> +<li><a name="TOC16" href="#SEC16">USING EBCDIC CODE</a> +<li><a name="TOC17" href="#SEC17">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a> +<li><a name="TOC18" href="#SEC18">PCREGREP BUFFER SIZE</a> +<li><a name="TOC19" href="#SEC19">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a> +<li><a name="TOC20" href="#SEC20">DEBUGGING WITH VALGRIND SUPPORT</a> +<li><a name="TOC21" href="#SEC21">CODE COVERAGE REPORTING</a> +<li><a name="TOC22" href="#SEC22">SEE ALSO</a> +<li><a name="TOC23" href="#SEC23">AUTHOR</a> +<li><a name="TOC24" href="#SEC24">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">BUILDING PCRE</a><br> +<P> +PCRE is distributed with a <b>configure</b> script that can be used to build the +library in Unix-like environments using the applications known as Autotools. +Also in the distribution are files to support building using <b>CMake</b> +instead of <b>configure</b>. The text file +<a href="README.txt"><b>README</b></a> +contains general information about building with Autotools (some of which is +repeated below), and also has some comments about building on various operating +systems. There is a lot more information about building PCRE without using +Autotools (including information about using <b>CMake</b> and building "by +hand") in the text file called +<a href="NON-AUTOTOOLS-BUILD.txt"><b>NON-AUTOTOOLS-BUILD</b>.</a> +You should consult this file as well as the +<a href="README.txt"><b>README</b></a> +file if you are building in a non-Unix-like environment. +</P> +<br><a name="SEC2" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br> +<P> +The rest of this document describes the optional features of PCRE that can be +selected when the library is compiled. It assumes use of the <b>configure</b> +script, where the optional features are selected or deselected by providing +options to <b>configure</b> before running the <b>make</b> command. However, the +same options can be selected in both Unix-like and non-Unix-like environments +using the GUI facility of <b>cmake-gui</b> if you are using <b>CMake</b> instead +of <b>configure</b> to build PCRE. +</P> +<P> +If you are not using Autotools or <b>CMake</b>, option selection can be done by +editing the <b>config.h</b> file, or by passing parameter settings to the +compiler, as described in +<a href="NON-AUTOTOOLS-BUILD.txt"><b>NON-AUTOTOOLS-BUILD</b>.</a> +</P> +<P> +The complete list of options for <b>configure</b> (which includes the standard +ones such as the selection of the installation directory) can be obtained by +running +<pre> + ./configure --help +</pre> +The following sections include descriptions of options whose names begin with +--enable or --disable. These settings specify changes to the defaults for the +<b>configure</b> command. Because of the way that <b>configure</b> works, +--enable and --disable always come in pairs, so the complementary option always +exists as well, but as it specifies the default, it is not described. +</P> +<br><a name="SEC3" href="#TOC1">BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a><br> +<P> +By default, a library called <b>libpcre</b> is built, containing functions that +take string arguments contained in vectors of bytes, either as single-byte +characters, or interpreted as UTF-8 strings. You can also build a separate +library, called <b>libpcre16</b>, in which strings are contained in vectors of +16-bit data units and interpreted either as single-unit characters or UTF-16 +strings, by adding +<pre> + --enable-pcre16 +</pre> +to the <b>configure</b> command. You can also build yet another separate +library, called <b>libpcre32</b>, in which strings are contained in vectors of +32-bit data units and interpreted either as single-unit characters or UTF-32 +strings, by adding +<pre> + --enable-pcre32 +</pre> +to the <b>configure</b> command. If you do not want the 8-bit library, add +<pre> + --disable-pcre8 +</pre> +as well. At least one of the three libraries must be built. Note that the C++ +and POSIX wrappers are for the 8-bit library only, and that <b>pcregrep</b> is +an 8-bit program. None of these are built if you select only the 16-bit or +32-bit libraries. +</P> +<br><a name="SEC4" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br> +<P> +The Autotools PCRE building process uses <b>libtool</b> to build both shared and +static libraries by default. You can suppress one of these by adding one of +<pre> + --disable-shared + --disable-static +</pre> +to the <b>configure</b> command, as required. +</P> +<br><a name="SEC5" href="#TOC1">C++ SUPPORT</a><br> +<P> +By default, if the 8-bit library is being built, the <b>configure</b> script +will search for a C++ compiler and C++ header files. If it finds them, it +automatically builds the C++ wrapper library (which supports only 8-bit +strings). You can disable this by adding +<pre> + --disable-cpp +</pre> +to the <b>configure</b> command. +</P> +<br><a name="SEC6" href="#TOC1">UTF-8, UTF-16 AND UTF-32 SUPPORT</a><br> +<P> +To build PCRE with support for UTF Unicode character strings, add +<pre> + --enable-utf +</pre> +to the <b>configure</b> command. This setting applies to all three libraries, +adding support for UTF-8 to the 8-bit library, support for UTF-16 to the 16-bit +library, and support for UTF-32 to the to the 32-bit library. There are no +separate options for enabling UTF-8, UTF-16 and UTF-32 independently because +that would allow ridiculous settings such as requesting UTF-16 support while +building only the 8-bit library. It is not possible to build one library with +UTF support and another without in the same configuration. (For backwards +compatibility, --enable-utf8 is a synonym of --enable-utf.) +</P> +<P> +Of itself, this setting does not make PCRE treat strings as UTF-8, UTF-16 or +UTF-32. As well as compiling PCRE with this option, you also have have to set +the PCRE_UTF8, PCRE_UTF16 or PCRE_UTF32 option (as appropriate) when you call +one of the pattern compiling functions. +</P> +<P> +If you set --enable-utf when compiling in an EBCDIC environment, PCRE expects +its input to be either ASCII or UTF-8 (depending on the run-time option). It is +not possible to support both EBCDIC and UTF-8 codes in the same version of the +library. Consequently, --enable-utf and --enable-ebcdic are mutually +exclusive. +</P> +<br><a name="SEC7" href="#TOC1">UNICODE CHARACTER PROPERTY SUPPORT</a><br> +<P> +UTF support allows the libraries to process character codepoints up to 0x10ffff +in the strings that they handle. On its own, however, it does not provide any +facilities for accessing the properties of such characters. If you want to be +able to use the pattern escapes \P, \p, and \X, which refer to Unicode +character properties, you must add +<pre> + --enable-unicode-properties +</pre> +to the <b>configure</b> command. This implies UTF support, even if you have +not explicitly requested it. +</P> +<P> +Including Unicode property support adds around 30K of tables to the PCRE +library. Only the general category properties such as <i>Lu</i> and <i>Nd</i> are +supported. Details are given in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. +</P> +<br><a name="SEC8" href="#TOC1">JUST-IN-TIME COMPILER SUPPORT</a><br> +<P> +Just-in-time compiler support is included in the build by specifying +<pre> + --enable-jit +</pre> +This support is available only for certain hardware architectures. If this +option is set for an unsupported architecture, a compile time error occurs. +See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for a discussion of JIT usage. When JIT support is enabled, +pcregrep automatically makes use of it, unless you add +<pre> + --disable-pcregrep-jit +</pre> +to the "configure" command. +</P> +<br><a name="SEC9" href="#TOC1">CODE VALUE OF NEWLINE</a><br> +<P> +By default, PCRE interprets the linefeed (LF) character as indicating the end +of a line. This is the normal newline character on Unix-like systems. You can +compile PCRE to use carriage return (CR) instead, by adding +<pre> + --enable-newline-is-cr +</pre> +to the <b>configure</b> command. There is also a --enable-newline-is-lf option, +which explicitly specifies linefeed as the newline character. +<br> +<br> +Alternatively, you can specify that line endings are to be indicated by the two +character sequence CRLF. If you want this, add +<pre> + --enable-newline-is-crlf +</pre> +to the <b>configure</b> command. There is a fourth option, specified by +<pre> + --enable-newline-is-anycrlf +</pre> +which causes PCRE to recognize any of the three sequences CR, LF, or CRLF as +indicating a line ending. Finally, a fifth option, specified by +<pre> + --enable-newline-is-any +</pre> +causes PCRE to recognize any Unicode newline sequence. +</P> +<P> +Whatever line ending convention is selected when PCRE is built can be +overridden when the library functions are called. At build time it is +conventional to use the standard for your operating system. +</P> +<br><a name="SEC10" href="#TOC1">WHAT \R MATCHES</a><br> +<P> +By default, the sequence \R in a pattern matches any Unicode newline sequence, +whatever has been selected as the line ending sequence. If you specify +<pre> + --enable-bsr-anycrlf +</pre> +the default is changed so that \R matches only CR, LF, or CRLF. Whatever is +selected when PCRE is built can be overridden when the library functions are +called. +</P> +<br><a name="SEC11" href="#TOC1">POSIX MALLOC USAGE</a><br> +<P> +When the 8-bit library is called through the POSIX interface (see the +<a href="pcreposix.html"><b>pcreposix</b></a> +documentation), additional working storage is required for holding the pointers +to capturing substrings, because PCRE requires three integers per substring, +whereas the POSIX interface provides only two. If the number of expected +substrings is small, the wrapper function uses space on the stack, because this +is faster than using <b>malloc()</b> for each call. The default threshold above +which the stack is no longer used is 10; it can be changed by adding a setting +such as +<pre> + --with-posix-malloc-threshold=20 +</pre> +to the <b>configure</b> command. +</P> +<br><a name="SEC12" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br> +<P> +Within a compiled pattern, offset values are used to point from one part to +another (for example, from an opening parenthesis to an alternation +metacharacter). By default, in the 8-bit and 16-bit libraries, two-byte values +are used for these offsets, leading to a maximum size for a compiled pattern of +around 64K. This is sufficient to handle all but the most gigantic patterns. +Nevertheless, some people do want to process truly enormous patterns, so it is +possible to compile PCRE to use three-byte or four-byte offsets by adding a +setting such as +<pre> + --with-link-size=3 +</pre> +to the <b>configure</b> command. The value given must be 2, 3, or 4. For the +16-bit library, a value of 3 is rounded up to 4. In these libraries, using +longer offsets slows down the operation of PCRE because it has to load +additional data when handling them. For the 32-bit library the value is always +4 and cannot be overridden; the value of --with-link-size is ignored. +</P> +<br><a name="SEC13" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br> +<P> +When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking +by making recursive calls to an internal function called <b>match()</b>. In +environments where the size of the stack is limited, this can severely limit +PCRE's operation. (The Unix environment does not usually suffer from this +problem, but it may sometimes be necessary to increase the maximum stack size. +There is a discussion in the +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation.) An alternative approach to recursion that uses memory from the +heap to remember data, instead of using recursive function calls, has been +implemented to work round the problem of limited stack size. If you want to +build a version of PCRE that works this way, add +<pre> + --disable-stack-for-recursion +</pre> +to the <b>configure</b> command. With this configuration, PCRE will use the +<b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory +management functions. By default these point to <b>malloc()</b> and +<b>free()</b>, but you can replace the pointers so that your own functions are +used instead. +</P> +<P> +Separate functions are provided rather than using <b>pcre_malloc</b> and +<b>pcre_free</b> because the usage is very predictable: the block sizes +requested are always the same, and the blocks are always freed in reverse +order. A calling program might be able to implement optimized functions that +perform better than <b>malloc()</b> and <b>free()</b>. PCRE runs noticeably more +slowly when built in this way. This option affects only the <b>pcre_exec()</b> +function; it is not relevant for <b>pcre_dfa_exec()</b>. +</P> +<br><a name="SEC14" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br> +<P> +Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly +(sometimes recursively) when matching a pattern with the <b>pcre_exec()</b> +function. By controlling the maximum number of times this function may be +called during a single matching operation, a limit can be placed on the +resources used by a single call to <b>pcre_exec()</b>. The limit can be changed +at run time, as described in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. The default is 10 million, but this can be changed by adding a +setting such as +<pre> + --with-match-limit=500000 +</pre> +to the <b>configure</b> command. This setting has no effect on the +<b>pcre_dfa_exec()</b> matching function. +</P> +<P> +In some environments it is desirable to limit the depth of recursive calls of +<b>match()</b> more strictly than the total number of calls, in order to +restrict the maximum amount of stack (or heap, if --disable-stack-for-recursion +is specified) that is used. A second limit controls this; it defaults to the +value that is set for --with-match-limit, which imposes no additional +constraints. However, you can set a lower limit by adding, for example, +<pre> + --with-match-limit-recursion=10000 +</pre> +to the <b>configure</b> command. This value can also be overridden at run time. +</P> +<br><a name="SEC15" href="#TOC1">CREATING CHARACTER TABLES AT BUILD TIME</a><br> +<P> +PCRE uses fixed tables for processing characters whose code values are less +than 256. By default, PCRE is built with a set of tables that are distributed +in the file <i>pcre_chartables.c.dist</i>. These tables are for ASCII codes +only. If you add +<pre> + --enable-rebuild-chartables +</pre> +to the <b>configure</b> command, the distributed tables are no longer used. +Instead, a program called <b>dftables</b> is compiled and run. This outputs the +source for new set of tables, created in the default locale of your C run-time +system. (This method of replacing the tables does not work if you are cross +compiling, because <b>dftables</b> is run on the local host. If you need to +create alternative tables when cross compiling, you will have to do so "by +hand".) +</P> +<br><a name="SEC16" href="#TOC1">USING EBCDIC CODE</a><br> +<P> +PCRE assumes by default that it will run in an environment where the character +code is ASCII (or Unicode, which is a superset of ASCII). This is the case for +most computer operating systems. PCRE can, however, be compiled to run in an +EBCDIC environment by adding +<pre> + --enable-ebcdic +</pre> +to the <b>configure</b> command. This setting implies +--enable-rebuild-chartables. You should only use it if you know that you are in +an EBCDIC environment (for example, an IBM mainframe operating system). The +--enable-ebcdic option is incompatible with --enable-utf. +</P> +<P> +The EBCDIC character that corresponds to an ASCII LF is assumed to have the +value 0x15 by default. However, in some EBCDIC environments, 0x25 is used. In +such an environment you should use +<pre> + --enable-ebcdic-nl25 +</pre> +as well as, or instead of, --enable-ebcdic. The EBCDIC character for CR has the +same value as in ASCII, namely, 0x0d. Whichever of 0x15 and 0x25 is <i>not</i> +chosen as LF is made to correspond to the Unicode NEL character (which, in +Unicode, is 0x85). +</P> +<P> +The options that select newline behaviour, such as --enable-newline-is-cr, +and equivalent run-time options, refer to these character values in an EBCDIC +environment. +</P> +<br><a name="SEC17" href="#TOC1">PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT</a><br> +<P> +By default, <b>pcregrep</b> reads all files as plain text. You can build it so +that it recognizes files whose names end in <b>.gz</b> or <b>.bz2</b>, and reads +them with <b>libz</b> or <b>libbz2</b>, respectively, by adding one or both of +<pre> + --enable-pcregrep-libz + --enable-pcregrep-libbz2 +</pre> +to the <b>configure</b> command. These options naturally require that the +relevant libraries are installed on your system. Configuration will fail if +they are not. +</P> +<br><a name="SEC18" href="#TOC1">PCREGREP BUFFER SIZE</a><br> +<P> +<b>pcregrep</b> uses an internal buffer to hold a "window" on the file it is +scanning, in order to be able to output "before" and "after" lines when it +finds a match. The size of the buffer is controlled by a parameter whose +default value is 20K. The buffer itself is three times this size, but because +of the way it is used for holding "before" lines, the longest line that is +guaranteed to be processable is the parameter size. You can change the default +parameter value by adding, for example, +<pre> + --with-pcregrep-bufsize=50K +</pre> +to the <b>configure</b> command. The caller of \fPpcregrep\fP can, however, +override this value by specifying a run-time option. +</P> +<br><a name="SEC19" href="#TOC1">PCRETEST OPTION FOR LIBREADLINE SUPPORT</a><br> +<P> +If you add +<pre> + --enable-pcretest-libreadline +</pre> +to the <b>configure</b> command, <b>pcretest</b> is linked with the +<b>libreadline</b> library, and when its input is from a terminal, it reads it +using the <b>readline()</b> function. This provides line-editing and history +facilities. Note that <b>libreadline</b> is GPL-licensed, so if you distribute a +binary of <b>pcretest</b> linked in this way, there may be licensing issues. +</P> +<P> +Setting this option causes the <b>-lreadline</b> option to be added to the +<b>pcretest</b> build. In many operating environments with a sytem-installed +<b>libreadline</b> this is sufficient. However, in some environments (e.g. +if an unmodified distribution version of readline is in use), some extra +configuration may be necessary. The INSTALL file for <b>libreadline</b> says +this: +<pre> + "Readline uses the termcap functions, but does not link with the + termcap or curses library itself, allowing applications which link + with readline the to choose an appropriate library." +</pre> +If your environment has not been set up so that an appropriate library is +automatically included, you may need to add something like +<pre> + LIBS="-ncurses" +</pre> +immediately before the <b>configure</b> command. +</P> +<br><a name="SEC20" href="#TOC1">DEBUGGING WITH VALGRIND SUPPORT</a><br> +<P> +By adding the +<pre> + --enable-valgrind +</pre> +option to to the <b>configure</b> command, PCRE will use valgrind annotations +to mark certain memory regions as unaddressable. This allows it to detect +invalid memory accesses, and is mostly useful for debugging PCRE itself. +</P> +<br><a name="SEC21" href="#TOC1">CODE COVERAGE REPORTING</a><br> +<P> +If your C compiler is gcc, you can build a version of PCRE that can generate a +code coverage report for its test suite. To enable this, you must install +<b>lcov</b> version 1.6 or above. Then specify +<pre> + --enable-coverage +</pre> +to the <b>configure</b> command and build PCRE in the usual way. +</P> +<P> +Note that using <b>ccache</b> (a caching C compiler) is incompatible with code +coverage reporting. If you have configured <b>ccache</b> to run automatically +on your system, you must set the environment variable +<pre> + CCACHE_DISABLE=1 +</pre> +before running <b>make</b> to build PCRE, so that <b>ccache</b> is not used. +</P> +<P> +When --enable-coverage is used, the following addition targets are added to the +<i>Makefile</i>: +<pre> + make coverage +</pre> +This creates a fresh coverage report for the PCRE test suite. It is equivalent +to running "make coverage-reset", "make coverage-baseline", "make check", and +then "make coverage-report". +<pre> + make coverage-reset +</pre> +This zeroes the coverage counters, but does nothing else. +<pre> + make coverage-baseline +</pre> +This captures baseline coverage information. +<pre> + make coverage-report +</pre> +This creates the coverage report. +<pre> + make coverage-clean-report +</pre> +This removes the generated coverage report without cleaning the coverage data +itself. +<pre> + make coverage-clean-data +</pre> +This removes the captured coverage data without removing the coverage files +created at compile time (*.gcno). +<pre> + make coverage-clean +</pre> +This cleans all coverage data including the generated coverage report. For more +information about code coverage, see the <b>gcov</b> and <b>lcov</b> +documentation. +</P> +<br><a name="SEC22" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcreapi</b>(3), <b>pcre16</b>, <b>pcre32</b>, <b>pcre_config</b>(3). +</P> +<br><a name="SEC23" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC24" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 May 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrecallout.html b/doc/html/pcrecallout.html new file mode 100644 index 0000000..53a937f --- /dev/null +++ b/doc/html/pcrecallout.html @@ -0,0 +1,286 @@ +<html> +<head> +<title>pcrecallout specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrecallout man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> +<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> +<li><a name="TOC3" href="#SEC3">MISSING CALLOUTS</a> +<li><a name="TOC4" href="#SEC4">THE CALLOUT INTERFACE</a> +<li><a name="TOC5" href="#SEC5">RETURN VALUES</a> +<li><a name="TOC6" href="#SEC6">AUTHOR</a> +<li><a name="TOC7" href="#SEC7">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> +<P> +<b>#include <pcre.h></b> +</P> +<P> +<b>int (*pcre_callout)(pcre_callout_block *);</b> +</P> +<P> +<b>int (*pcre16_callout)(pcre16_callout_block *);</b> +</P> +<P> +<b>int (*pcre32_callout)(pcre32_callout_block *);</b> +</P> +<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> +<P> +PCRE provides a feature called "callout", which is a means of temporarily +passing control to the caller of PCRE in the middle of pattern matching. The +caller of PCRE provides an external function by putting its entry point in the +global variable <i>pcre_callout</i> (<i>pcre16_callout</i> for the 16-bit +library, <i>pcre32_callout</i> for the 32-bit library). By default, this +variable contains NULL, which disables all calling out. +</P> +<P> +Within a regular expression, (?C) indicates the points at which the external +function is to be called. Different callout points can be identified by putting +a number less than 256 after the letter C. The default value is zero. +For example, this pattern has two callout points: +<pre> + (?C1)abc(?C2)def +</pre> +If the PCRE_AUTO_CALLOUT option bit is set when a pattern is compiled, PCRE +automatically inserts callouts, all with number 255, before each item in the +pattern. For example, if PCRE_AUTO_CALLOUT is used with the pattern +<pre> + A(\d{2}|--) +</pre> +it is processed as if it were +<br> +<br> +(?C255)A(?C255)((?C255)\d{2}(?C255)|(?C255)-(?C255)-(?C255))(?C255) +<br> +<br> +Notice that there is a callout before and after each parenthesis and +alternation bar. If the pattern contains a conditional group whose condition is +an assertion, an automatic callout is inserted immediately before the +condition. Such a callout may also be inserted explicitly, for example: +<pre> + (?(?C9)(?=a)ab|de) +</pre> +This applies only to assertion conditions (because they are themselves +independent groups). +</P> +<P> +Automatic callouts can be used for tracking the progress of pattern matching. +The +<a href="pcretest.html"><b>pcretest</b></a> +program has a pattern qualifier (/C) that sets automatic callouts; when it is +used, the output indicates how the pattern is being matched. This is useful +information when you are trying to optimize the performance of a particular +pattern. +</P> +<br><a name="SEC3" href="#TOC1">MISSING CALLOUTS</a><br> +<P> +You should be aware that, because of optimizations in the way PCRE compiles and +matches patterns, callouts sometimes do not happen exactly as you might expect. +</P> +<P> +At compile time, PCRE "auto-possessifies" repeated items when it knows that +what follows cannot be part of the repeat. For example, a+[bc] is compiled as +if it were a++[bc]. The <b>pcretest</b> output when this pattern is anchored and +then applied with automatic callouts to the string "aaaa" is: +<pre> + --->aaaa + +0 ^ ^ + +1 ^ a+ + +3 ^ ^ [bc] + No match +</pre> +This indicates that when matching [bc] fails, there is no backtracking into a+ +and therefore the callouts that would be taken for the backtracks do not occur. +You can disable the auto-possessify feature by passing PCRE_NO_AUTO_POSSESS +to <b>pcre_compile()</b>, or starting the pattern with (*NO_AUTO_POSSESS). If +this is done in <b>pcretest</b> (using the /O qualifier), the output changes to +this: +<pre> + --->aaaa + +0 ^ ^ + +1 ^ a+ + +3 ^ ^ [bc] + +3 ^ ^ [bc] + +3 ^ ^ [bc] + +3 ^^ [bc] + No match +</pre> +This time, when matching [bc] fails, the matcher backtracks into a+ and tries +again, repeatedly, until a+ itself fails. +</P> +<P> +Other optimizations that provide fast "no match" results also affect callouts. +For example, if the pattern is +<pre> + ab(?C4)cd +</pre> +PCRE knows that any matching string must contain the letter "d". If the subject +string is "abyz", the lack of "d" means that matching doesn't ever start, and +the callout is never reached. However, with "abyd", though the result is still +no match, the callout is obeyed. +</P> +<P> +If the pattern is studied, PCRE knows the minimum length of a matching string, +and will immediately give a "no match" return without actually running a match +if the subject is not long enough, or, for unanchored patterns, if it has +been scanned far enough. +</P> +<P> +You can disable these optimizations by passing the PCRE_NO_START_OPTIMIZE +option to the matching function, or by starting the pattern with +(*NO_START_OPT). This slows down the matching process, but does ensure that +callouts such as the example above are obeyed. +</P> +<br><a name="SEC4" href="#TOC1">THE CALLOUT INTERFACE</a><br> +<P> +During matching, when PCRE reaches a callout point, the external function +defined by <i>pcre_callout</i> or <i>pcre[16|32]_callout</i> is called (if it is +set). This applies to both normal and DFA matching. The only argument to the +callout function is a pointer to a <b>pcre_callout</b> or +<b>pcre[16|32]_callout</b> block. These structures contains the following +fields: +<pre> + int <i>version</i>; + int <i>callout_number</i>; + int *<i>offset_vector</i>; + const char *<i>subject</i>; (8-bit version) + PCRE_SPTR16 <i>subject</i>; (16-bit version) + PCRE_SPTR32 <i>subject</i>; (32-bit version) + int <i>subject_length</i>; + int <i>start_match</i>; + int <i>current_position</i>; + int <i>capture_top</i>; + int <i>capture_last</i>; + void *<i>callout_data</i>; + int <i>pattern_position</i>; + int <i>next_item_length</i>; + const unsigned char *<i>mark</i>; (8-bit version) + const PCRE_UCHAR16 *<i>mark</i>; (16-bit version) + const PCRE_UCHAR32 *<i>mark</i>; (32-bit version) +</pre> +The <i>version</i> field is an integer containing the version number of the +block format. The initial version was 0; the current version is 2. The version +number will change again in future if additional fields are added, but the +intention is never to remove any of the existing fields. +</P> +<P> +The <i>callout_number</i> field contains the number of the callout, as compiled +into the pattern (that is, the number after ?C for manual callouts, and 255 for +automatically generated callouts). +</P> +<P> +The <i>offset_vector</i> field is a pointer to the vector of offsets that was +passed by the caller to the matching function. When <b>pcre_exec()</b> or +<b>pcre[16|32]_exec()</b> is used, the contents can be inspected, in order to +extract substrings that have been matched so far, in the same way as for +extracting substrings after a match has completed. For the DFA matching +functions, this field is not useful. +</P> +<P> +The <i>subject</i> and <i>subject_length</i> fields contain copies of the values +that were passed to the matching function. +</P> +<P> +The <i>start_match</i> field normally contains the offset within the subject at +which the current match attempt started. However, if the escape sequence \K +has been encountered, this value is changed to reflect the modified starting +point. If the pattern is not anchored, the callout function may be called +several times from the same point in the pattern for different starting points +in the subject. +</P> +<P> +The <i>current_position</i> field contains the offset within the subject of the +current match pointer. +</P> +<P> +When the <b>pcre_exec()</b> or <b>pcre[16|32]_exec()</b> is used, the +<i>capture_top</i> field contains one more than the number of the highest +numbered captured substring so far. If no substrings have been captured, the +value of <i>capture_top</i> is one. This is always the case when the DFA +functions are used, because they do not support captured substrings. +</P> +<P> +The <i>capture_last</i> field contains the number of the most recently captured +substring. However, when a recursion exits, the value reverts to what it was +outside the recursion, as do the values of all captured substrings. If no +substrings have been captured, the value of <i>capture_last</i> is -1. This is +always the case for the DFA matching functions. +</P> +<P> +The <i>callout_data</i> field contains a value that is passed to a matching +function specifically so that it can be passed back in callouts. It is passed +in the <i>callout_data</i> field of a <b>pcre_extra</b> or <b>pcre[16|32]_extra</b> +data structure. If no such data was passed, the value of <i>callout_data</i> in +a callout block is NULL. There is a description of the <b>pcre_extra</b> +structure in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<P> +The <i>pattern_position</i> field is present from version 1 of the callout +structure. It contains the offset to the next item to be matched in the pattern +string. +</P> +<P> +The <i>next_item_length</i> field is present from version 1 of the callout +structure. It contains the length of the next item to be matched in the pattern +string. When the callout immediately precedes an alternation bar, a closing +parenthesis, or the end of the pattern, the length is zero. When the callout +precedes an opening parenthesis, the length is that of the entire subpattern. +</P> +<P> +The <i>pattern_position</i> and <i>next_item_length</i> fields are intended to +help in distinguishing between different automatic callouts, which all have the +same callout number. However, they are set for all callouts. +</P> +<P> +The <i>mark</i> field is present from version 2 of the callout structure. In +callouts from <b>pcre_exec()</b> or <b>pcre[16|32]_exec()</b> it contains a +pointer to the zero-terminated name of the most recently passed (*MARK), +(*PRUNE), or (*THEN) item in the match, or NULL if no such items have been +passed. Instances of (*PRUNE) or (*THEN) without a name do not obliterate a +previous (*MARK). In callouts from the DFA matching functions this field always +contains NULL. +</P> +<br><a name="SEC5" href="#TOC1">RETURN VALUES</a><br> +<P> +The external callout function returns an integer to PCRE. If the value is zero, +matching proceeds as normal. If the value is greater than zero, matching fails +at the current point, but the testing of other matching possibilities goes +ahead, just as if a lookahead assertion had failed. If the value is less than +zero, the match is abandoned, the matching function returns the negative value. +</P> +<P> +Negative values should normally be chosen from the set of PCRE_ERROR_xxx +values. In particular, PCRE_ERROR_NOMATCH forces a standard "no match" failure. +The error number PCRE_ERROR_CALLOUT is reserved for use by callout functions; +it will never be used by PCRE itself. +</P> +<br><a name="SEC6" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC7" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 November 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrecompat.html b/doc/html/pcrecompat.html new file mode 100644 index 0000000..3e62266 --- /dev/null +++ b/doc/html/pcrecompat.html @@ -0,0 +1,235 @@ +<html> +<head> +<title>pcrecompat specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrecompat man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +DIFFERENCES BETWEEN PCRE AND PERL +</b><br> +<P> +This document describes the differences in the ways that PCRE and Perl handle +regular expressions. The differences described here are with respect to Perl +versions 5.10 and above. +</P> +<P> +1. PCRE has only a subset of Perl's Unicode support. Details of what it does +have are given in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. +</P> +<P> +2. PCRE allows repeat quantifiers only on parenthesized assertions, but they do +not mean what you might think. For example, (?!a){3} does not assert that the +next three characters are not "a". It just asserts that the next character is +not "a" three times (in principle: PCRE optimizes this to run the assertion +just once). Perl allows repeat quantifiers on other assertions such as \b, but +these do not seem to have any use. +</P> +<P> +3. Capturing subpatterns that occur inside negative lookahead assertions are +counted, but their entries in the offsets vector are never set. Perl sometimes +(but not always) sets its numerical variables from inside negative assertions. +</P> +<P> +4. Though binary zero characters are supported in the subject string, they are +not allowed in a pattern string because it is passed as a normal C string, +terminated by zero. The escape sequence \0 can be used in the pattern to +represent a binary zero. +</P> +<P> +5. The following Perl escape sequences are not supported: \l, \u, \L, +\U, and \N when followed by a character name or Unicode value. (\N on its +own, matching a non-newline character, is supported.) In fact these are +implemented by Perl's general string-handling and are not part of its pattern +matching engine. If any of these are encountered by PCRE, an error is +generated by default. However, if the PCRE_JAVASCRIPT_COMPAT option is set, +\U and \u are interpreted as JavaScript interprets them. +</P> +<P> +6. The Perl escape sequences \p, \P, and \X are supported only if PCRE is +built with Unicode character property support. The properties that can be +tested with \p and \P are limited to the general category properties such as +Lu and Nd, script names such as Greek or Han, and the derived properties Any +and L&. PCRE does support the Cs (surrogate) property, which Perl does not; the +Perl documentation says "Because Perl hides the need for the user to understand +the internal representation of Unicode characters, there is no need to +implement the somewhat messy concept of surrogates." +</P> +<P> +7. PCRE does support the \Q...\E escape for quoting substrings. Characters in +between are treated as literals. This is slightly different from Perl in that $ +and @ are also handled as literals inside the quotes. In Perl, they cause +variable interpolation (but of course PCRE does not have variables). Note the +following examples: +<pre> + Pattern PCRE matches Perl matches + + \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz + \Qabc\$xyz\E abc\$xyz abc\$xyz + \Qabc\E\$\Qxyz\E abc$xyz abc$xyz +</pre> +The \Q...\E sequence is recognized both inside and outside character classes. +</P> +<P> +8. Fairly obviously, PCRE does not support the (?{code}) and (??{code}) +constructions. However, there is support for recursive patterns. This is not +available in Perl 5.8, but it is in Perl 5.10. Also, the PCRE "callout" +feature allows an external function to be called during pattern matching. See +the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation for details. +</P> +<P> +9. Subpatterns that are called as subroutines (whether or not recursively) are +always treated as atomic groups in PCRE. This is like Python, but unlike Perl. +Captured values that are set outside a subroutine call can be reference from +inside in PCRE, but not in Perl. There is a discussion that explains these +differences in more detail in the +<a href="pcrepattern.html#recursiondifference">section on recursion differences from Perl</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +page. +</P> +<P> +10. If any of the backtracking control verbs are used in a subpattern that is +called as a subroutine (whether or not recursively), their effect is confined +to that subpattern; it does not extend to the surrounding pattern. This is not +always the case in Perl. In particular, if (*THEN) is present in a group that +is called as a subroutine, its action is limited to that group, even if the +group does not contain any | characters. Note that such subpatterns are +processed as anchored at the point where they are tested. +</P> +<P> +11. If a pattern contains more than one backtracking control verb, the first +one that is backtracked onto acts. For example, in the pattern +A(*COMMIT)B(*PRUNE)C a failure in B triggers (*COMMIT), but a failure in C +triggers (*PRUNE). Perl's behaviour is more complex; in many cases it is the +same as PCRE, but there are examples where it differs. +</P> +<P> +12. Most backtracking verbs in assertions have their normal actions. They are +not confined to the assertion. +</P> +<P> +13. There are some differences that are concerned with the settings of captured +strings when part of a pattern is repeated. For example, matching "aba" against +the pattern /^(a(b)?)+$/ in Perl leaves $2 unset, but in PCRE it is set to "b". +</P> +<P> +14. PCRE's handling of duplicate subpattern numbers and duplicate subpattern +names is not as general as Perl's. This is a consequence of the fact the PCRE +works internally just with numbers, using an external table to translate +between numbers and names. In particular, a pattern such as (?|(?<a>A)|(?<b)B), +where the two capturing parentheses have the same number but different names, +is not supported, and causes an error at compile time. If it were allowed, it +would not be possible to distinguish which parentheses matched, because both +names map to capturing subpattern number 1. To avoid this confusing situation, +an error is given at compile time. +</P> +<P> +15. Perl recognizes comments in some places that PCRE does not, for example, +between the ( and ? at the start of a subpattern. If the /x modifier is set, +Perl allows white space between ( and ? (though current Perls warn that this is +deprecated) but PCRE never does, even if the PCRE_EXTENDED option is set. +</P> +<P> +16. Perl, when in warning mode, gives warnings for character classes such as +[A-\d] or [a-[:digit:]]. It then treats the hyphens as literals. PCRE has no +warning features, so it gives an error in these cases because they are almost +certainly user mistakes. +</P> +<P> +17. In PCRE, the upper/lower case character properties Lu and Ll are not +affected when case-independent matching is specified. For example, \p{Lu} +always matches an upper case letter. I think Perl has changed in this respect; +in the release at the time of writing (5.16), \p{Lu} and \p{Ll} match all +letters, regardless of case, when case independence is specified. +</P> +<P> +18. PCRE provides some extensions to the Perl regular expression facilities. +Perl 5.10 includes new features that are not in earlier versions of Perl, some +of which (such as named parentheses) have been in PCRE for some time. This list +is with respect to Perl 5.10: +<br> +<br> +(a) Although lookbehind assertions in PCRE must match fixed length strings, +each alternative branch of a lookbehind assertion can match a different length +of string. Perl requires them all to have the same length. +<br> +<br> +(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ +meta-character matches only at the very end of the string. +<br> +<br> +(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special +meaning is faulted. Otherwise, like Perl, the backslash is quietly ignored. +(Perl can be made to issue a warning.) +<br> +<br> +(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is +inverted, that is, by default they are not greedy, but if followed by a +question mark they are. +<br> +<br> +(e) PCRE_ANCHORED can be used at matching time to force a pattern to be tried +only at the first matching position in the subject string. +<br> +<br> +(f) The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART, and +PCRE_NO_AUTO_CAPTURE options for <b>pcre_exec()</b> have no Perl equivalents. +<br> +<br> +(g) The \R escape sequence can be restricted to match only CR, LF, or CRLF +by the PCRE_BSR_ANYCRLF option. +<br> +<br> +(h) The callout facility is PCRE-specific. +<br> +<br> +(i) The partial matching facility is PCRE-specific. +<br> +<br> +(j) Patterns compiled by PCRE can be saved and re-used at a later time, even on +different hosts that have the other endianness. However, this does not apply to +optimized data created by the just-in-time compiler. +<br> +<br> +(k) The alternative matching functions (<b>pcre_dfa_exec()</b>, +<b>pcre16_dfa_exec()</b> and <b>pcre32_dfa_exec()</b>,) match in a different way +and are not Perl-compatible. +<br> +<br> +(l) PCRE recognizes some special sequences such as (*CR) at the start of +a pattern that set overall options that cannot be changed within the pattern. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 10 November 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrecpp.html b/doc/html/pcrecpp.html new file mode 100644 index 0000000..b7eac3a --- /dev/null +++ b/doc/html/pcrecpp.html @@ -0,0 +1,368 @@ +<html> +<head> +<title>pcrecpp specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrecpp man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS OF C++ WRAPPER</a> +<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> +<li><a name="TOC3" href="#SEC3">MATCHING INTERFACE</a> +<li><a name="TOC4" href="#SEC4">QUOTING METACHARACTERS</a> +<li><a name="TOC5" href="#SEC5">PARTIAL MATCHES</a> +<li><a name="TOC6" href="#SEC6">UTF-8 AND THE MATCHING INTERFACE</a> +<li><a name="TOC7" href="#SEC7">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a> +<li><a name="TOC8" href="#SEC8">SCANNING TEXT INCREMENTALLY</a> +<li><a name="TOC9" href="#SEC9">PARSING HEX/OCTAL/C-RADIX NUMBERS</a> +<li><a name="TOC10" href="#SEC10">REPLACING PARTS OF STRINGS</a> +<li><a name="TOC11" href="#SEC11">AUTHOR</a> +<li><a name="TOC12" href="#SEC12">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS OF C++ WRAPPER</a><br> +<P> +<b>#include <pcrecpp.h></b> +</P> +<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> +<P> +The C++ wrapper for PCRE was provided by Google Inc. Some additional +functionality was added by Giuseppe Maxia. This brief man page was constructed +from the notes in the <i>pcrecpp.h</i> file, which should be consulted for +further details. Note that the C++ wrapper supports only the original 8-bit +PCRE library. There is no 16-bit or 32-bit support at present. +</P> +<br><a name="SEC3" href="#TOC1">MATCHING INTERFACE</a><br> +<P> +The "FullMatch" operation checks that supplied text matches a supplied pattern +exactly. If pointer arguments are supplied, it copies matched sub-strings that +match sub-patterns into them. +<pre> + Example: successful match + pcrecpp::RE re("h.*o"); + re.FullMatch("hello"); + + Example: unsuccessful match (requires full match): + pcrecpp::RE re("e"); + !re.FullMatch("hello"); + + Example: creating a temporary RE object: + pcrecpp::RE("h.*o").FullMatch("hello"); +</pre> +You can pass in a "const char*" or a "string" for "text". The examples below +tend to use a const char*. You can, as in the different examples above, store +the RE object explicitly in a variable or use a temporary RE object. The +examples below use one mode or the other arbitrarily. Either could correctly be +used for any of these examples. +</P> +<P> +You must supply extra pointer arguments to extract matched subpieces. +<pre> + Example: extracts "ruby" into "s" and 1234 into "i" + int i; + string s; + pcrecpp::RE re("(\\w+):(\\d+)"); + re.FullMatch("ruby:1234", &s, &i); + + Example: does not try to extract any extra sub-patterns + re.FullMatch("ruby:1234", &s); + + Example: does not try to extract into NULL + re.FullMatch("ruby:1234", NULL, &i); + + Example: integer overflow causes failure + !re.FullMatch("ruby:1234567891234", NULL, &i); + + Example: fails because there aren't enough sub-patterns: + !pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s); + + Example: fails because string cannot be stored in integer + !pcrecpp::RE("(.*)").FullMatch("ruby", &i); +</pre> +The provided pointer arguments can be pointers to any scalar numeric +type, or one of: +<pre> + string (matched piece is copied to string) + StringPiece (StringPiece is mutated to point to matched piece) + T (where "bool T::ParseFrom(const char*, int)" exists) + NULL (the corresponding matched sub-pattern is not copied) +</pre> +The function returns true iff all of the following conditions are satisfied: +<pre> + a. "text" matches "pattern" exactly; + + b. The number of matched sub-patterns is >= number of supplied + pointers; + + c. The "i"th argument has a suitable type for holding the + string captured as the "i"th sub-pattern. If you pass in + void * NULL for the "i"th argument, or a non-void * NULL + of the correct type, or pass fewer arguments than the + number of sub-patterns, "i"th captured sub-pattern is + ignored. +</pre> +CAVEAT: An optional sub-pattern that does not exist in the matched +string is assigned the empty string. Therefore, the following will +return false (because the empty string is not a valid number): +<pre> + int number; + pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number); +</pre> +The matching interface supports at most 16 arguments per call. +If you need more, consider using the more general interface +<b>pcrecpp::RE::DoMatch</b>. See <b>pcrecpp.h</b> for the signature for +<b>DoMatch</b>. +</P> +<P> +NOTE: Do not use <b>no_arg</b>, which is used internally to mark the end of a +list of optional arguments, as a placeholder for missing arguments, as this can +lead to segfaults. +</P> +<br><a name="SEC4" href="#TOC1">QUOTING METACHARACTERS</a><br> +<P> +You can use the "QuoteMeta" operation to insert backslashes before all +potentially meaningful characters in a string. The returned string, used as a +regular expression, will exactly match the original string. +<pre> + Example: + string quoted = RE::QuoteMeta(unquoted); +</pre> +Note that it's legal to escape a character even if it has no special meaning in +a regular expression -- so this function does that. (This also makes it +identical to the perl function of the same name; see "perldoc -f quotemeta".) +For example, "1.5-2.0?" becomes "1\.5\-2\.0\?". +</P> +<br><a name="SEC5" href="#TOC1">PARTIAL MATCHES</a><br> +<P> +You can use the "PartialMatch" operation when you want the pattern +to match any substring of the text. +<pre> + Example: simple search for a string: + pcrecpp::RE("ell").PartialMatch("hello"); + + Example: find first number in a string: + int number; + pcrecpp::RE re("(\\d+)"); + re.PartialMatch("x*100 + 20", &number); + assert(number == 100); +</PRE> +</P> +<br><a name="SEC6" href="#TOC1">UTF-8 AND THE MATCHING INTERFACE</a><br> +<P> +By default, pattern and text are plain text, one byte per character. The UTF8 +flag, passed to the constructor, causes both pattern and string to be treated +as UTF-8 text, still a byte stream but potentially multiple bytes per +character. In practice, the text is likelier to be UTF-8 than the pattern, but +the match returned may depend on the UTF8 flag, so always use it when matching +UTF8 text. For example, "." will match one byte normally but with UTF8 set may +match up to three bytes of a multi-byte character. +<pre> + Example: + pcrecpp::RE_Options options; + options.set_utf8(); + pcrecpp::RE re(utf8_pattern, options); + re.FullMatch(utf8_string); + + Example: using the convenience function UTF8(): + pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8()); + re.FullMatch(utf8_string); +</pre> +NOTE: The UTF8 flag is ignored if pcre was not configured with the +<pre> + --enable-utf8 flag. +</PRE> +</P> +<br><a name="SEC7" href="#TOC1">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a><br> +<P> +PCRE defines some modifiers to change the behavior of the regular expression +engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to +pass such modifiers to a RE class. Currently, the following modifiers are +supported: +<pre> + modifier description Perl corresponding + + PCRE_CASELESS case insensitive match /i + PCRE_MULTILINE multiple lines match /m + PCRE_DOTALL dot matches newlines /s + PCRE_DOLLAR_ENDONLY $ matches only at end N/A + PCRE_EXTRA strict escape parsing N/A + PCRE_EXTENDED ignore white spaces /x + PCRE_UTF8 handles UTF8 chars built-in + PCRE_UNGREEDY reverses * and *? N/A + PCRE_NO_AUTO_CAPTURE disables capturing parens N/A (*) +</pre> +(*) Both Perl and PCRE allow non capturing parentheses by means of the +"?:" modifier within the pattern itself. e.g. (?:ab|cd) does not +capture, while (ab|cd) does. +</P> +<P> +For a full account on how each modifier works, please check the +PCRE API reference page. +</P> +<P> +For each modifier, there are two member functions whose name is made +out of the modifier in lowercase, without the "PCRE_" prefix. For +instance, PCRE_CASELESS is handled by +<pre> + bool caseless() +</pre> +which returns true if the modifier is set, and +<pre> + RE_Options & set_caseless(bool) +</pre> +which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be +accessed through the <b>set_match_limit()</b> and <b>match_limit()</b> member +functions. Setting <i>match_limit</i> to a non-zero value will limit the +execution of pcre to keep it from doing bad things like blowing the stack or +taking an eternity to return a result. A value of 5000 is good enough to stop +stack blowup in a 2MB thread stack. Setting <i>match_limit</i> to zero disables +match limiting. Alternatively, you can call <b>match_limit_recursion()</b> +which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE +recurses. <b>match_limit()</b> limits the number of matches PCRE does; +<b>match_limit_recursion()</b> limits the depth of internal recursion, and +therefore the amount of stack that is used. +</P> +<P> +Normally, to pass one or more modifiers to a RE class, you declare +a <i>RE_Options</i> object, set the appropriate options, and pass this +object to a RE constructor. Example: +<pre> + RE_Options opt; + opt.set_caseless(true); + if (RE("HELLO", opt).PartialMatch("hello world")) ... +</pre> +RE_options has two constructors. The default constructor takes no arguments and +creates a set of flags that are off by default. The optional parameter +<i>option_flags</i> is to facilitate transfer of legacy code from C programs. +This lets you do +<pre> + RE(pattern, + RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str); +</pre> +However, new code is better off doing +<pre> + RE(pattern, + RE_Options().set_caseless(true).set_multiline(true)) + .PartialMatch(str); +</pre> +If you are going to pass one of the most used modifiers, there are some +convenience functions that return a RE_Options class with the +appropriate modifier already set: <b>CASELESS()</b>, <b>UTF8()</b>, +<b>MULTILINE()</b>, <b>DOTALL</b>(), and <b>EXTENDED()</b>. +</P> +<P> +If you need to set several options at once, and you don't want to go through +the pains of declaring a RE_Options object and setting several options, there +is a parallel method that give you such ability on the fly. You can concatenate +several <b>set_xxxxx()</b> member functions, since each of them returns a +reference to its class object. For example, to pass PCRE_CASELESS, +PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write: +<pre> + RE(" ^ xyz \\s+ .* blah$", + RE_Options() + .set_caseless(true) + .set_extended(true) + .set_multiline(true)).PartialMatch(sometext); + +</PRE> +</P> +<br><a name="SEC8" href="#TOC1">SCANNING TEXT INCREMENTALLY</a><br> +<P> +The "Consume" operation may be useful if you want to repeatedly +match regular expressions at the front of a string and skip over +them as they match. This requires use of the "StringPiece" type, +which represents a sub-range of a real string. Like RE, StringPiece +is defined in the pcrecpp namespace. +<pre> + Example: read lines of the form "var = value" from a string. + string contents = ...; // Fill string somehow + pcrecpp::StringPiece input(contents); // Wrap in a StringPiece + + string var; + int value; + pcrecpp::RE re("(\\w+) = (\\d+)\n"); + while (re.Consume(&input, &var, &value)) { + ...; + } +</pre> +Each successful call to "Consume" will set "var/value", and also +advance "input" so it points past the matched text. +</P> +<P> +The "FindAndConsume" operation is similar to "Consume" but does not +anchor your match at the beginning of the string. For example, you +could extract all words from a string by repeatedly calling +<pre> + pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word) +</PRE> +</P> +<br><a name="SEC9" href="#TOC1">PARSING HEX/OCTAL/C-RADIX NUMBERS</a><br> +<P> +By default, if you pass a pointer to a numeric value, the +corresponding text is interpreted as a base-10 number. You can +instead wrap the pointer with a call to one of the operators Hex(), +Octal(), or CRadix() to interpret the text in another base. The +CRadix operator interprets C-style "0" (base-8) and "0x" (base-16) +prefixes, but defaults to base-10. +<pre> + Example: + int a, b, c, d; + pcrecpp::RE re("(.*) (.*) (.*) (.*)"); + re.FullMatch("100 40 0100 0x40", + pcrecpp::Octal(&a), pcrecpp::Hex(&b), + pcrecpp::CRadix(&c), pcrecpp::CRadix(&d)); +</pre> +will leave 64 in a, b, c, and d. +</P> +<br><a name="SEC10" href="#TOC1">REPLACING PARTS OF STRINGS</a><br> +<P> +You can replace the first match of "pattern" in "str" with "rewrite". +Within "rewrite", backslash-escaped digits (\1 to \9) can be +used to insert text matching corresponding parenthesized group +from the pattern. \0 in "rewrite" refers to the entire matching +text. For example: +<pre> + string s = "yabba dabba doo"; + pcrecpp::RE("b+").Replace("d", &s); +</pre> +will leave "s" containing "yada dabba doo". The result is true if the pattern +matches and a replacement occurs, false otherwise. +</P> +<P> +<b>GlobalReplace</b> is like <b>Replace</b> except that it replaces all +occurrences of the pattern in the string with the rewrite. Replacements are +not subject to re-matching. For example: +<pre> + string s = "yabba dabba doo"; + pcrecpp::RE("b+").GlobalReplace("d", &s); +</pre> +will leave "s" containing "yada dada doo". It returns the number of +replacements made. +</P> +<P> +<b>Extract</b> is like <b>Replace</b>, except that if the pattern matches, +"rewrite" is copied into "out" (an additional argument) with substitutions. +The non-matching portions of "text" are ignored. Returns true iff a match +occurred and the extraction happened successfully; if no match occurs, the +string is left unaffected. +</P> +<br><a name="SEC11" href="#TOC1">AUTHOR</a><br> +<P> +The C++ wrapper was contributed by Google Inc. +<br> +Copyright © 2007 Google Inc. +<br> +</P> +<br><a name="SEC12" href="#TOC1">REVISION</a><br> +<P> +Last updated: 08 January 2012 +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcredemo.html b/doc/html/pcredemo.html new file mode 100644 index 0000000..894a930 --- /dev/null +++ b/doc/html/pcredemo.html @@ -0,0 +1,426 @@ +<html> +<head> +<title>pcredemo specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcredemo man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +</ul> +<PRE> +/************************************************* +* PCRE DEMONSTRATION PROGRAM * +*************************************************/ + +/* This is a demonstration program to illustrate the most straightforward ways +of calling the PCRE regular expression library from a C program. See the +pcresample documentation for a short discussion ("man pcresample" if you have +the PCRE man pages installed). + +In Unix-like environments, if PCRE is installed in your standard system +libraries, you should be able to compile this program using this command: + +gcc -Wall pcredemo.c -lpcre -o pcredemo + +If PCRE is not installed in a standard place, it is likely to be installed with +support for the pkg-config mechanism. If you have pkg-config, you can compile +this program using this command: + +gcc -Wall pcredemo.c `pkg-config --cflags --libs libpcre` -o pcredemo + +If you do not have pkg-config, you may have to use this: + +gcc -Wall pcredemo.c -I/usr/local/include -L/usr/local/lib \ + -R/usr/local/lib -lpcre -o pcredemo + +Replace "/usr/local/include" and "/usr/local/lib" with wherever the include and +library files for PCRE are installed on your system. Only some operating +systems (e.g. Solaris) use the -R option. + +Building under Windows: + +If you want to statically link this program against a non-dll .a file, you must +define PCRE_STATIC before including pcre.h, otherwise the pcre_malloc() and +pcre_free() exported functions will be declared __declspec(dllimport), with +unwanted results. So in this environment, uncomment the following line. */ + +/* #define PCRE_STATIC */ + +#include <stdio.h> +#include <string.h> +#include <pcre.h> + +#define OVECCOUNT 30 /* should be a multiple of 3 */ + + +int main(int argc, char **argv) +{ +pcre *re; +const char *error; +char *pattern; +char *subject; +unsigned char *name_table; +unsigned int option_bits; +int erroffset; +int find_all; +int crlf_is_newline; +int namecount; +int name_entry_size; +int ovector[OVECCOUNT]; +int subject_length; +int rc, i; +int utf8; + + +/************************************************************************** +* First, sort out the command line. There is only one possible option at * +* the moment, "-g" to request repeated matching to find all occurrences, * +* like Perl's /g option. We set the variable find_all to a non-zero value * +* if the -g option is present. Apart from that, there must be exactly two * +* arguments. * +**************************************************************************/ + +find_all = 0; +for (i = 1; i < argc; i++) + { + if (strcmp(argv[i], "-g") == 0) find_all = 1; + else break; + } + +/* After the options, we require exactly two arguments, which are the pattern, +and the subject string. */ + +if (argc - i != 2) + { + printf("Two arguments required: a regex and a subject string\n"); + return 1; + } + +pattern = argv[i]; +subject = argv[i+1]; +subject_length = (int)strlen(subject); + + +/************************************************************************* +* Now we are going to compile the regular expression pattern, and handle * +* and errors that are detected. * +*************************************************************************/ + +re = pcre_compile( + pattern, /* the pattern */ + 0, /* default options */ + &error, /* for error message */ + &erroffset, /* for error offset */ + NULL); /* use default character tables */ + +/* Compilation failed: print the error message and exit */ + +if (re == NULL) + { + printf("PCRE compilation failed at offset %d: %s\n", erroffset, error); + return 1; + } + + +/************************************************************************* +* If the compilation succeeded, we call PCRE again, in order to do a * +* pattern match against the subject string. This does just ONE match. If * +* further matching is needed, it will be done below. * +*************************************************************************/ + +rc = pcre_exec( + re, /* the compiled pattern */ + NULL, /* no extra data - we didn't study the pattern */ + subject, /* the subject string */ + subject_length, /* the length of the subject */ + 0, /* start at offset 0 in the subject */ + 0, /* default options */ + ovector, /* output vector for substring information */ + OVECCOUNT); /* number of elements in the output vector */ + +/* Matching failed: handle error cases */ + +if (rc < 0) + { + switch(rc) + { + case PCRE_ERROR_NOMATCH: printf("No match\n"); break; + /* + Handle other special cases if you like + */ + default: printf("Matching error %d\n", rc); break; + } + pcre_free(re); /* Release memory used for the compiled pattern */ + return 1; + } + +/* Match succeded */ + +printf("\nMatch succeeded at offset %d\n", ovector[0]); + + +/************************************************************************* +* We have found the first match within the subject string. If the output * +* vector wasn't big enough, say so. Then output any substrings that were * +* captured. * +*************************************************************************/ + +/* The output vector wasn't big enough */ + +if (rc == 0) + { + rc = OVECCOUNT/3; + printf("ovector only has room for %d captured substrings\n", rc - 1); + } + +/* Show substrings stored in the output vector by number. Obviously, in a real +application you might want to do things other than print them. */ + +for (i = 0; i < rc; i++) + { + char *substring_start = subject + ovector[2*i]; + int substring_length = ovector[2*i+1] - ovector[2*i]; + printf("%2d: %.*s\n", i, substring_length, substring_start); + } + + +/************************************************************************** +* That concludes the basic part of this demonstration program. We have * +* compiled a pattern, and performed a single match. The code that follows * +* shows first how to access named substrings, and then how to code for * +* repeated matches on the same subject. * +**************************************************************************/ + +/* See if there are any named substrings, and if so, show them by name. First +we have to extract the count of named parentheses from the pattern. */ + +(void)pcre_fullinfo( + re, /* the compiled pattern */ + NULL, /* no extra data - we didn't study the pattern */ + PCRE_INFO_NAMECOUNT, /* number of named substrings */ + &namecount); /* where to put the answer */ + +if (namecount <= 0) printf("No named substrings\n"); else + { + unsigned char *tabptr; + printf("Named substrings\n"); + + /* Before we can access the substrings, we must extract the table for + translating names to numbers, and the size of each entry in the table. */ + + (void)pcre_fullinfo( + re, /* the compiled pattern */ + NULL, /* no extra data - we didn't study the pattern */ + PCRE_INFO_NAMETABLE, /* address of the table */ + &name_table); /* where to put the answer */ + + (void)pcre_fullinfo( + re, /* the compiled pattern */ + NULL, /* no extra data - we didn't study the pattern */ + PCRE_INFO_NAMEENTRYSIZE, /* size of each entry in the table */ + &name_entry_size); /* where to put the answer */ + + /* Now we can scan the table and, for each entry, print the number, the name, + and the substring itself. */ + + tabptr = name_table; + for (i = 0; i < namecount; i++) + { + int n = (tabptr[0] << 8) | tabptr[1]; + printf("(%d) %*s: %.*s\n", n, name_entry_size - 3, tabptr + 2, + ovector[2*n+1] - ovector[2*n], subject + ovector[2*n]); + tabptr += name_entry_size; + } + } + + +/************************************************************************* +* If the "-g" option was given on the command line, we want to continue * +* to search for additional matches in the subject string, in a similar * +* way to the /g option in Perl. This turns out to be trickier than you * +* might think because of the possibility of matching an empty string. * +* What happens is as follows: * +* * +* If the previous match was NOT for an empty string, we can just start * +* the next match at the end of the previous one. * +* * +* If the previous match WAS for an empty string, we can't do that, as it * +* would lead to an infinite loop. Instead, a special call of pcre_exec() * +* is made with the PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED flags set. * +* The first of these tells PCRE that an empty string at the start of the * +* subject is not a valid match; other possibilities must be tried. The * +* second flag restricts PCRE to one match attempt at the initial string * +* position. If this match succeeds, an alternative to the empty string * +* match has been found, and we can print it and proceed round the loop, * +* advancing by the length of whatever was found. If this match does not * +* succeed, we still stay in the loop, advancing by just one character. * +* In UTF-8 mode, which can be set by (*UTF8) in the pattern, this may be * +* more than one byte. * +* * +* However, there is a complication concerned with newlines. When the * +* newline convention is such that CRLF is a valid newline, we must * +* advance by two characters rather than one. The newline convention can * +* be set in the regex by (*CR), etc.; if not, we must find the default. * +*************************************************************************/ + +if (!find_all) /* Check for -g */ + { + pcre_free(re); /* Release the memory used for the compiled pattern */ + return 0; /* Finish unless -g was given */ + } + +/* Before running the loop, check for UTF-8 and whether CRLF is a valid newline +sequence. First, find the options with which the regex was compiled; extract +the UTF-8 state, and mask off all but the newline options. */ + +(void)pcre_fullinfo(re, NULL, PCRE_INFO_OPTIONS, &option_bits); +utf8 = option_bits & PCRE_UTF8; +option_bits &= PCRE_NEWLINE_CR|PCRE_NEWLINE_LF|PCRE_NEWLINE_CRLF| + PCRE_NEWLINE_ANY|PCRE_NEWLINE_ANYCRLF; + +/* If no newline options were set, find the default newline convention from the +build configuration. */ + +if (option_bits == 0) + { + int d; + (void)pcre_config(PCRE_CONFIG_NEWLINE, &d); + /* Note that these values are always the ASCII ones, even in + EBCDIC environments. CR = 13, NL = 10. */ + option_bits = (d == 13)? PCRE_NEWLINE_CR : + (d == 10)? PCRE_NEWLINE_LF : + (d == (13<<8 | 10))? PCRE_NEWLINE_CRLF : + (d == -2)? PCRE_NEWLINE_ANYCRLF : + (d == -1)? PCRE_NEWLINE_ANY : 0; + } + +/* See if CRLF is a valid newline sequence. */ + +crlf_is_newline = + option_bits == PCRE_NEWLINE_ANY || + option_bits == PCRE_NEWLINE_CRLF || + option_bits == PCRE_NEWLINE_ANYCRLF; + +/* Loop for second and subsequent matches */ + +for (;;) + { + int options = 0; /* Normally no options */ + int start_offset = ovector[1]; /* Start at end of previous match */ + + /* If the previous match was for an empty string, we are finished if we are + at the end of the subject. Otherwise, arrange to run another match at the + same point to see if a non-empty match can be found. */ + + if (ovector[0] == ovector[1]) + { + if (ovector[0] == subject_length) break; + options = PCRE_NOTEMPTY_ATSTART | PCRE_ANCHORED; + } + + /* Run the next matching operation */ + + rc = pcre_exec( + re, /* the compiled pattern */ + NULL, /* no extra data - we didn't study the pattern */ + subject, /* the subject string */ + subject_length, /* the length of the subject */ + start_offset, /* starting offset in the subject */ + options, /* options */ + ovector, /* output vector for substring information */ + OVECCOUNT); /* number of elements in the output vector */ + + /* This time, a result of NOMATCH isn't an error. If the value in "options" + is zero, it just means we have found all possible matches, so the loop ends. + Otherwise, it means we have failed to find a non-empty-string match at a + point where there was a previous empty-string match. In this case, we do what + Perl does: advance the matching position by one character, and continue. We + do this by setting the "end of previous match" offset, because that is picked + up at the top of the loop as the point at which to start again. + + There are two complications: (a) When CRLF is a valid newline sequence, and + the current position is just before it, advance by an extra byte. (b) + Otherwise we must ensure that we skip an entire UTF-8 character if we are in + UTF-8 mode. */ + + if (rc == PCRE_ERROR_NOMATCH) + { + if (options == 0) break; /* All matches found */ + ovector[1] = start_offset + 1; /* Advance one byte */ + if (crlf_is_newline && /* If CRLF is newline & */ + start_offset < subject_length - 1 && /* we are at CRLF, */ + subject[start_offset] == '\r' && + subject[start_offset + 1] == '\n') + ovector[1] += 1; /* Advance by one more. */ + else if (utf8) /* Otherwise, ensure we */ + { /* advance a whole UTF-8 */ + while (ovector[1] < subject_length) /* character. */ + { + if ((subject[ovector[1]] & 0xc0) != 0x80) break; + ovector[1] += 1; + } + } + continue; /* Go round the loop again */ + } + + /* Other matching errors are not recoverable. */ + + if (rc < 0) + { + printf("Matching error %d\n", rc); + pcre_free(re); /* Release memory used for the compiled pattern */ + return 1; + } + + /* Match succeded */ + + printf("\nMatch succeeded again at offset %d\n", ovector[0]); + + /* The match succeeded, but the output vector wasn't big enough. */ + + if (rc == 0) + { + rc = OVECCOUNT/3; + printf("ovector only has room for %d captured substrings\n", rc - 1); + } + + /* As before, show substrings stored in the output vector by number, and then + also any named substrings. */ + + for (i = 0; i < rc; i++) + { + char *substring_start = subject + ovector[2*i]; + int substring_length = ovector[2*i+1] - ovector[2*i]; + printf("%2d: %.*s\n", i, substring_length, substring_start); + } + + if (namecount <= 0) printf("No named substrings\n"); else + { + unsigned char *tabptr = name_table; + printf("Named substrings\n"); + for (i = 0; i < namecount; i++) + { + int n = (tabptr[0] << 8) | tabptr[1]; + printf("(%d) %*s: %.*s\n", n, name_entry_size - 3, tabptr + 2, + ovector[2*n+1] - ovector[2*n], subject + ovector[2*n]); + tabptr += name_entry_size; + } + } + } /* End of loop to find second and subsequent matches */ + +printf("\n"); +pcre_free(re); /* Release memory used for the compiled pattern */ +return 0; +} + +/* End of pcredemo.c */ +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcregrep.html b/doc/html/pcregrep.html new file mode 100644 index 0000000..dacbb49 --- /dev/null +++ b/doc/html/pcregrep.html @@ -0,0 +1,759 @@ +<html> +<head> +<title>pcregrep specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcregrep man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> +<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> +<li><a name="TOC3" href="#SEC3">SUPPORT FOR COMPRESSED FILES</a> +<li><a name="TOC4" href="#SEC4">BINARY FILES</a> +<li><a name="TOC5" href="#SEC5">OPTIONS</a> +<li><a name="TOC6" href="#SEC6">ENVIRONMENT VARIABLES</a> +<li><a name="TOC7" href="#SEC7">NEWLINES</a> +<li><a name="TOC8" href="#SEC8">OPTIONS COMPATIBILITY</a> +<li><a name="TOC9" href="#SEC9">OPTIONS WITH DATA</a> +<li><a name="TOC10" href="#SEC10">MATCHING ERRORS</a> +<li><a name="TOC11" href="#SEC11">DIAGNOSTICS</a> +<li><a name="TOC12" href="#SEC12">SEE ALSO</a> +<li><a name="TOC13" href="#SEC13">AUTHOR</a> +<li><a name="TOC14" href="#SEC14">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> +<P> +<b>pcregrep [options] [long options] [pattern] [path1 path2 ...]</b> +</P> +<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> +<P> +<b>pcregrep</b> searches files for character patterns, in the same way as other +grep commands do, but it uses the PCRE regular expression library to support +patterns that are compatible with the regular expressions of Perl 5. See +<a href="pcresyntax.html"><b>pcresyntax</b>(3)</a> +for a quick-reference summary of pattern syntax, or +<a href="pcrepattern.html"><b>pcrepattern</b>(3)</a> +for a full description of the syntax and semantics of the regular expressions +that PCRE supports. +</P> +<P> +Patterns, whether supplied on the command line or in a separate file, are given +without delimiters. For example: +<pre> + pcregrep Thursday /etc/motd +</pre> +If you attempt to use delimiters (for example, by surrounding a pattern with +slashes, as is common in Perl scripts), they are interpreted as part of the +pattern. Quotes can of course be used to delimit patterns on the command line +because they are interpreted by the shell, and indeed quotes are required if a +pattern contains white space or shell metacharacters. +</P> +<P> +The first argument that follows any option settings is treated as the single +pattern to be matched when neither <b>-e</b> nor <b>-f</b> is present. +Conversely, when one or both of these options are used to specify patterns, all +arguments are treated as path names. At least one of <b>-e</b>, <b>-f</b>, or an +argument pattern must be provided. +</P> +<P> +If no files are specified, <b>pcregrep</b> reads the standard input. The +standard input can also be referenced by a name consisting of a single hyphen. +For example: +<pre> + pcregrep some-pattern /file1 - /file3 +</pre> +By default, each line that matches a pattern is copied to the standard +output, and if there is more than one file, the file name is output at the +start of each line, followed by a colon. However, there are options that can +change how <b>pcregrep</b> behaves. In particular, the <b>-M</b> option makes it +possible to search for patterns that span line boundaries. What defines a line +boundary is controlled by the <b>-N</b> (<b>--newline</b>) option. +</P> +<P> +The amount of memory used for buffering files that are being scanned is +controlled by a parameter that can be set by the <b>--buffer-size</b> option. +The default value for this parameter is specified when <b>pcregrep</b> is built, +with the default default being 20K. A block of memory three times this size is +used (to allow for buffering "before" and "after" lines). An error occurs if a +line overflows the buffer. +</P> +<P> +Patterns can be no longer than 8K or BUFSIZ bytes, whichever is the greater. +BUFSIZ is defined in <b><stdio.h></b>. When there is more than one pattern +(specified by the use of <b>-e</b> and/or <b>-f</b>), each pattern is applied to +each line in the order in which they are defined, except that all the <b>-e</b> +patterns are tried before the <b>-f</b> patterns. +</P> +<P> +By default, as soon as one pattern matches a line, no further patterns are +considered. However, if <b>--colour</b> (or <b>--color</b>) is used to colour the +matching substrings, or if <b>--only-matching</b>, <b>--file-offsets</b>, or +<b>--line-offsets</b> is used to output only the part of the line that matched +(either shown literally, or as an offset), scanning resumes immediately +following the match, so that further matches on the same line can be found. If +there are multiple patterns, they are all tried on the remainder of the line, +but patterns that follow the one that matched are not tried on the earlier part +of the line. +</P> +<P> +This behaviour means that the order in which multiple patterns are specified +can affect the output when one of the above options is used. This is no longer +the same behaviour as GNU grep, which now manages to display earlier matches +for later patterns (as long as there is no overlap). +</P> +<P> +Patterns that can match an empty string are accepted, but empty string +matches are never recognized. An example is the pattern "(super)?(man)?", in +which all components are optional. This pattern finds all occurrences of both +"super" and "man"; the output differs from matching with "super|man" when only +the matching substrings are being shown. +</P> +<P> +If the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variable is set, +<b>pcregrep</b> uses the value to set a locale when calling the PCRE library. +The <b>--locale</b> option can be used to override this. +</P> +<br><a name="SEC3" href="#TOC1">SUPPORT FOR COMPRESSED FILES</a><br> +<P> +It is possible to compile <b>pcregrep</b> so that it uses <b>libz</b> or +<b>libbz2</b> to read files whose names end in <b>.gz</b> or <b>.bz2</b>, +respectively. You can find out whether your binary has support for one or both +of these file types by running it with the <b>--help</b> option. If the +appropriate support is not present, files are treated as plain text. The +standard input is always so treated. +</P> +<br><a name="SEC4" href="#TOC1">BINARY FILES</a><br> +<P> +By default, a file that contains a binary zero byte within the first 1024 bytes +is identified as a binary file, and is processed specially. (GNU grep also +identifies binary files in this manner.) See the <b>--binary-files</b> option +for a means of changing the way binary files are handled. +</P> +<br><a name="SEC5" href="#TOC1">OPTIONS</a><br> +<P> +The order in which some of the options appear can affect the output. For +example, both the <b>-h</b> and <b>-l</b> options affect the printing of file +names. Whichever comes later in the command line will be the one that takes +effect. Similarly, except where noted below, if an option is given twice, the +later setting is used. Numerical values for options may be followed by K or M, +to signify multiplication by 1024 or 1024*1024 respectively. +</P> +<P> +<b>--</b> +This terminates the list of options. It is useful if the next item on the +command line starts with a hyphen but is not an option. This allows for the +processing of patterns and filenames that start with hyphens. +</P> +<P> +<b>-A</b> <i>number</i>, <b>--after-context=</b><i>number</i> +Output <i>number</i> lines of context after each matching line. If filenames +and/or line numbers are being output, a hyphen separator is used instead of a +colon for the context lines. A line containing "--" is output between each +group of lines, unless they are in fact contiguous in the input file. The value +of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b> +guarantees to have up to 8K of following text available for context output. +</P> +<P> +<b>-a</b>, <b>--text</b> +Treat binary files as text. This is equivalent to +<b>--binary-files</b>=<i>text</i>. +</P> +<P> +<b>-B</b> <i>number</i>, <b>--before-context=</b><i>number</i> +Output <i>number</i> lines of context before each matching line. If filenames +and/or line numbers are being output, a hyphen separator is used instead of a +colon for the context lines. A line containing "--" is output between each +group of lines, unless they are in fact contiguous in the input file. The value +of <i>number</i> is expected to be relatively small. However, <b>pcregrep</b> +guarantees to have up to 8K of preceding text available for context output. +</P> +<P> +<b>--binary-files=</b><i>word</i> +Specify how binary files are to be processed. If the word is "binary" (the +default), pattern matching is performed on binary files, but the only output is +"Binary file <name> matches" when a match succeeds. If the word is "text", +which is equivalent to the <b>-a</b> or <b>--text</b> option, binary files are +processed in the same way as any other file. In this case, when a match +succeeds, the output may be binary garbage, which can have nasty effects if +sent to a terminal. If the word is "without-match", which is equivalent to the +<b>-I</b> option, binary files are not processed at all; they are assumed not to +be of interest. +</P> +<P> +<b>--buffer-size=</b><i>number</i> +Set the parameter that controls how much memory is used for buffering files +that are being scanned. +</P> +<P> +<b>-C</b> <i>number</i>, <b>--context=</b><i>number</i> +Output <i>number</i> lines of context both before and after each matching line. +This is equivalent to setting both <b>-A</b> and <b>-B</b> to the same value. +</P> +<P> +<b>-c</b>, <b>--count</b> +Do not output individual lines from the files that are being scanned; instead +output the number of lines that would otherwise have been shown. If no lines +are selected, the number zero is output. If several files are are being +scanned, a count is output for each of them. However, if the +<b>--files-with-matches</b> option is also used, only those files whose counts +are greater than zero are listed. When <b>-c</b> is used, the <b>-A</b>, +<b>-B</b>, and <b>-C</b> options are ignored. +</P> +<P> +<b>--colour</b>, <b>--color</b> +If this option is given without any data, it is equivalent to "--colour=auto". +If data is required, it must be given in the same shell item, separated by an +equals sign. +</P> +<P> +<b>--colour=</b><i>value</i>, <b>--color=</b><i>value</i> +This option specifies under what circumstances the parts of a line that matched +a pattern should be coloured in the output. By default, the output is not +coloured. The value (which is optional, see above) may be "never", "always", or +"auto". In the latter case, colouring happens only if the standard output is +connected to a terminal. More resources are used when colouring is enabled, +because <b>pcregrep</b> has to search for all possible matches in a line, not +just one, in order to colour them all. +<br> +<br> +The colour that is used can be specified by setting the environment variable +PCREGREP_COLOUR or PCREGREP_COLOR. The value of this variable should be a +string of two numbers, separated by a semicolon. They are copied directly into +the control string for setting colour on a terminal, so it is your +responsibility to ensure that they make sense. If neither of the environment +variables is set, the default is "1;31", which gives red. +</P> +<P> +<b>-D</b> <i>action</i>, <b>--devices=</b><i>action</i> +If an input path is not a regular file or a directory, "action" specifies how +it is to be processed. Valid values are "read" (the default) or "skip" +(silently skip the path). +</P> +<P> +<b>-d</b> <i>action</i>, <b>--directories=</b><i>action</i> +If an input path is a directory, "action" specifies how it is to be processed. +Valid values are "read" (the default in non-Windows environments, for +compatibility with GNU grep), "recurse" (equivalent to the <b>-r</b> option), or +"skip" (silently skip the path, the default in Windows environments). In the +"read" case, directories are read as if they were ordinary files. In some +operating systems the effect of reading a directory like this is an immediate +end-of-file; in others it may provoke an error. +</P> +<P> +<b>-e</b> <i>pattern</i>, <b>--regex=</b><i>pattern</i>, <b>--regexp=</b><i>pattern</i> +Specify a pattern to be matched. This option can be used multiple times in +order to specify several patterns. It can also be used as a way of specifying a +single pattern that starts with a hyphen. When <b>-e</b> is used, no argument +pattern is taken from the command line; all arguments are treated as file +names. There is no limit to the number of patterns. They are applied to each +line in the order in which they are defined until one matches. +<br> +<br> +If <b>-f</b> is used with <b>-e</b>, the command line patterns are matched first, +followed by the patterns from the file(s), independent of the order in which +these options are specified. Note that multiple use of <b>-e</b> is not the same +as a single pattern with alternatives. For example, X|Y finds the first +character in a line that is X or Y, whereas if the two patterns are given +separately, with X first, <b>pcregrep</b> finds X if it is present, even if it +follows Y in the line. It finds Y only if there is no X in the line. This +matters only if you are using <b>-o</b> or <b>--colo(u)r</b> to show the part(s) +of the line that matched. +</P> +<P> +<b>--exclude</b>=<i>pattern</i> +Files (but not directories) whose names match the pattern are skipped without +being processed. This applies to all files, whether listed on the command line, +obtained from <b>--file-list</b>, or by scanning a directory. The pattern is a +PCRE regular expression, and is matched against the final component of the file +name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not +apply to this pattern. The option may be given any number of times in order to +specify multiple patterns. If a file name matches both an <b>--include</b> +and an <b>--exclude</b> pattern, it is excluded. There is no short form for this +option. +</P> +<P> +<b>--exclude-from=</b><i>filename</i> +Treat each non-empty line of the file as the data for an <b>--exclude</b> +option. What constitutes a newline when reading the file is the operating +system's default. The <b>--newline</b> option has no effect on this option. This +option may be given more than once in order to specify a number of files to +read. +</P> +<P> +<b>--exclude-dir</b>=<i>pattern</i> +Directories whose names match the pattern are skipped without being processed, +whatever the setting of the <b>--recursive</b> option. This applies to all +directories, whether listed on the command line, obtained from +<b>--file-list</b>, or by scanning a parent directory. The pattern is a PCRE +regular expression, and is matched against the final component of the directory +name, not the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not +apply to this pattern. The option may be given any number of times in order to +specify more than one pattern. If a directory matches both <b>--include-dir</b> +and <b>--exclude-dir</b>, it is excluded. There is no short form for this +option. +</P> +<P> +<b>-F</b>, <b>--fixed-strings</b> +Interpret each data-matching pattern as a list of fixed strings, separated by +newlines, instead of as a regular expression. What constitutes a newline for +this purpose is controlled by the <b>--newline</b> option. The <b>-w</b> (match +as a word) and <b>-x</b> (match whole line) options can be used with <b>-F</b>. +They apply to each of the fixed strings. A line is selected if any of the fixed +strings are found in it (subject to <b>-w</b> or <b>-x</b>, if present). This +option applies only to the patterns that are matched against the contents of +files; it does not apply to patterns specified by any of the <b>--include</b> or +<b>--exclude</b> options. +</P> +<P> +<b>-f</b> <i>filename</i>, <b>--file=</b><i>filename</i> +Read patterns from the file, one per line, and match them against +each line of input. What constitutes a newline when reading the file is the +operating system's default. The <b>--newline</b> option has no effect on this +option. Trailing white space is removed from each line, and blank lines are +ignored. An empty file contains no patterns and therefore matches nothing. See +also the comments about multiple patterns versus a single pattern with +alternatives in the description of <b>-e</b> above. +<br> +<br> +If this option is given more than once, all the specified files are +read. A data line is output if any of the patterns match it. A filename can +be given as "-" to refer to the standard input. When <b>-f</b> is used, patterns +specified on the command line using <b>-e</b> may also be present; they are +tested before the file's patterns. However, no other pattern is taken from the +command line; all arguments are treated as the names of paths to be searched. +</P> +<P> +<b>--file-list</b>=<i>filename</i> +Read a list of files and/or directories that are to be scanned from the given +file, one per line. Trailing white space is removed from each line, and blank +lines are ignored. These paths are processed before any that are listed on the +command line. The filename can be given as "-" to refer to the standard input. +If <b>--file</b> and <b>--file-list</b> are both specified as "-", patterns are +read first. This is useful only when the standard input is a terminal, from +which further lines (the list of files) can be read after an end-of-file +indication. If this option is given more than once, all the specified files are +read. +</P> +<P> +<b>--file-offsets</b> +Instead of showing lines or parts of lines that match, show each match as an +offset from the start of the file and a length, separated by a comma. In this +mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> +options are ignored. If there is more than one match in a line, each of them is +shown separately. This option is mutually exclusive with <b>--line-offsets</b> +and <b>--only-matching</b>. +</P> +<P> +<b>-H</b>, <b>--with-filename</b> +Force the inclusion of the filename at the start of output lines when searching +a single file. By default, the filename is not shown in this case. For matching +lines, the filename is followed by a colon; for context lines, a hyphen +separator is used. If a line number is also being output, it follows the file +name. +</P> +<P> +<b>-h</b>, <b>--no-filename</b> +Suppress the output filenames when searching multiple files. By default, +filenames are shown when multiple files are searched. For matching lines, the +filename is followed by a colon; for context lines, a hyphen separator is used. +If a line number is also being output, it follows the file name. +</P> +<P> +<b>--help</b> +Output a help message, giving brief details of the command options and file +type support, and then exit. Anything else on the command line is +ignored. +</P> +<P> +<b>-I</b> +Treat binary files as never matching. This is equivalent to +<b>--binary-files</b>=<i>without-match</i>. +</P> +<P> +<b>-i</b>, <b>--ignore-case</b> +Ignore upper/lower case distinctions during comparisons. +</P> +<P> +<b>--include</b>=<i>pattern</i> +If any <b>--include</b> patterns are specified, the only files that are +processed are those that match one of the patterns (and do not match an +<b>--exclude</b> pattern). This option does not affect directories, but it +applies to all files, whether listed on the command line, obtained from +<b>--file-list</b>, or by scanning a directory. The pattern is a PCRE regular +expression, and is matched against the final component of the file name, not +the entire path. The <b>-F</b>, <b>-w</b>, and <b>-x</b> options do not apply to +this pattern. The option may be given any number of times. If a file name +matches both an <b>--include</b> and an <b>--exclude</b> pattern, it is excluded. +There is no short form for this option. +</P> +<P> +<b>--include-from=</b><i>filename</i> +Treat each non-empty line of the file as the data for an <b>--include</b> +option. What constitutes a newline for this purpose is the operating system's +default. The <b>--newline</b> option has no effect on this option. This option +may be given any number of times; all the files are read. +</P> +<P> +<b>--include-dir</b>=<i>pattern</i> +If any <b>--include-dir</b> patterns are specified, the only directories that +are processed are those that match one of the patterns (and do not match an +<b>--exclude-dir</b> pattern). This applies to all directories, whether listed +on the command line, obtained from <b>--file-list</b>, or by scanning a parent +directory. The pattern is a PCRE regular expression, and is matched against the +final component of the directory name, not the entire path. The <b>-F</b>, +<b>-w</b>, and <b>-x</b> options do not apply to this pattern. The option may be +given any number of times. If a directory matches both <b>--include-dir</b> and +<b>--exclude-dir</b>, it is excluded. There is no short form for this option. +</P> +<P> +<b>-L</b>, <b>--files-without-match</b> +Instead of outputting lines from the files, just output the names of the files +that do not contain any lines that would have been output. Each file name is +output once, on a separate line. +</P> +<P> +<b>-l</b>, <b>--files-with-matches</b> +Instead of outputting lines from the files, just output the names of the files +containing lines that would have been output. Each file name is output +once, on a separate line. Searching normally stops as soon as a matching line +is found in a file. However, if the <b>-c</b> (count) option is also used, +matching continues in order to obtain the correct count, and those files that +have at least one match are listed along with their counts. Using this option +with <b>-c</b> is a way of suppressing the listing of files with no matches. +</P> +<P> +<b>--label</b>=<i>name</i> +This option supplies a name to be used for the standard input when file names +are being output. If not supplied, "(standard input)" is used. There is no +short form for this option. +</P> +<P> +<b>--line-buffered</b> +When this option is given, input is read and processed line by line, and the +output is flushed after each write. By default, input is read in large chunks, +unless <b>pcregrep</b> can determine that it is reading from a terminal (which +is currently possible only in Unix-like environments). Output to terminal is +normally automatically flushed by the operating system. This option can be +useful when the input or output is attached to a pipe and you do not want +<b>pcregrep</b> to buffer up large amounts of data. However, its use will affect +performance, and the <b>-M</b> (multiline) option ceases to work. +</P> +<P> +<b>--line-offsets</b> +Instead of showing lines or parts of lines that match, show each match as a +line number, the offset from the start of the line, and a length. The line +number is terminated by a colon (as usual; see the <b>-n</b> option), and the +offset and length are separated by a comma. In this mode, no context is shown. +That is, the <b>-A</b>, <b>-B</b>, and <b>-C</b> options are ignored. If there is +more than one match in a line, each of them is shown separately. This option is +mutually exclusive with <b>--file-offsets</b> and <b>--only-matching</b>. +</P> +<P> +<b>--locale</b>=<i>locale-name</i> +This option specifies a locale to be used for pattern matching. It overrides +the value in the <b>LC_ALL</b> or <b>LC_CTYPE</b> environment variables. If no +locale is specified, the PCRE library's default (usually the "C" locale) is +used. There is no short form for this option. +</P> +<P> +<b>--match-limit</b>=<i>number</i> +Processing some regular expression patterns can require a very large amount of +memory, leading in some cases to a program crash if not enough is available. +Other patterns may take a very long time to search for all possible matching +strings. The <b>pcre_exec()</b> function that is called by <b>pcregrep</b> to do +the matching has two parameters that can limit the resources that it uses. +<br> +<br> +The <b>--match-limit</b> option provides a means of limiting resource usage +when processing patterns that are not going to match, but which have a very +large number of possibilities in their search trees. The classic example is a +pattern that uses nested unlimited repeats. Internally, PCRE uses a function +called <b>match()</b> which it calls repeatedly (sometimes recursively). The +limit set by <b>--match-limit</b> is imposed on the number of times this +function is called during a match, which has the effect of limiting the amount +of backtracking that can take place. +<br> +<br> +The <b>--recursion-limit</b> option is similar to <b>--match-limit</b>, but +instead of limiting the total number of times that <b>match()</b> is called, it +limits the depth of recursive calls, which in turn limits the amount of memory +that can be used. The recursion depth is a smaller number than the total number +of calls, because not all calls to <b>match()</b> are recursive. This limit is +of use only if it is set smaller than <b>--match-limit</b>. +<br> +<br> +There are no short forms for these options. The default settings are specified +when the PCRE library is compiled, with the default default being 10 million. +</P> +<P> +<b>-M</b>, <b>--multiline</b> +Allow patterns to match more than one line. When this option is given, patterns +may usefully contain literal newline characters and internal occurrences of ^ +and $ characters. The output for a successful match may consist of more than +one line, the last of which is the one in which the match ended. If the matched +string ends with a newline sequence the output ends at the end of that line. +<br> +<br> +When this option is set, the PCRE library is called in "multiline" mode. +There is a limit to the number of lines that can be matched, imposed by the way +that <b>pcregrep</b> buffers the input file as it scans it. However, +<b>pcregrep</b> ensures that at least 8K characters or the rest of the document +(whichever is the shorter) are available for forward matching, and similarly +the previous 8K characters (or all the previous characters, if fewer than 8K) +are guaranteed to be available for lookbehind assertions. This option does not +work when input is read line by line (see \fP--line-buffered\fP.) +</P> +<P> +<b>-N</b> <i>newline-type</i>, <b>--newline</b>=<i>newline-type</i> +The PCRE library supports five different conventions for indicating +the ends of lines. They are the single-character sequences CR (carriage return) +and LF (linefeed), the two-character sequence CRLF, an "anycrlf" convention, +which recognizes any of the preceding three types, and an "any" convention, in +which any Unicode line ending sequence is assumed to end a line. The Unicode +sequences are the three just mentioned, plus VT (vertical tab, U+000B), FF +(form feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and +PS (paragraph separator, U+2029). +<br> +<br> +When the PCRE library is built, a default line-ending sequence is specified. +This is normally the standard sequence for the operating system. Unless +otherwise specified by this option, <b>pcregrep</b> uses the library's default. +The possible values for this option are CR, LF, CRLF, ANYCRLF, or ANY. This +makes it possible to use <b>pcregrep</b> to scan files that have come from other +environments without having to modify their line endings. If the data that is +being scanned does not agree with the convention set by this option, +<b>pcregrep</b> may behave in strange ways. Note that this option does not +apply to files specified by the <b>-f</b>, <b>--exclude-from</b>, or +<b>--include-from</b> options, which are expected to use the operating system's +standard newline sequence. +</P> +<P> +<b>-n</b>, <b>--line-number</b> +Precede each output line by its line number in the file, followed by a colon +for matching lines or a hyphen for context lines. If the filename is also being +output, it precedes the line number. This option is forced if +<b>--line-offsets</b> is used. +</P> +<P> +<b>--no-jit</b> +If the PCRE library is built with support for just-in-time compiling (which +speeds up matching), <b>pcregrep</b> automatically makes use of this, unless it +was explicitly disabled at build time. This option can be used to disable the +use of JIT at run time. It is provided for testing and working round problems. +It should never be needed in normal use. +</P> +<P> +<b>-o</b>, <b>--only-matching</b> +Show only the part of the line that matched a pattern instead of the whole +line. In this mode, no context is shown. That is, the <b>-A</b>, <b>-B</b>, and +<b>-C</b> options are ignored. If there is more than one match in a line, each +of them is shown separately. If <b>-o</b> is combined with <b>-v</b> (invert the +sense of the match to find non-matching lines), no output is generated, but the +return code is set appropriately. If the matched portion of the line is empty, +nothing is output unless the file name or line number are being printed, in +which case they are shown on an otherwise empty line. This option is mutually +exclusive with <b>--file-offsets</b> and <b>--line-offsets</b>. +</P> +<P> +<b>-o</b><i>number</i>, <b>--only-matching</b>=<i>number</i> +Show only the part of the line that matched the capturing parentheses of the +given number. Up to 32 capturing parentheses are supported, and -o0 is +equivalent to <b>-o</b> without a number. Because these options can be given +without an argument (see above), if an argument is present, it must be given in +the same shell item, for example, -o3 or --only-matching=2. The comments given +for the non-argument case above also apply to this case. If the specified +capturing parentheses do not exist in the pattern, or were not set in the +match, nothing is output unless the file name or line number are being printed. +<br> +<br> +If this option is given multiple times, multiple substrings are output, in the +order the options are given. For example, -o3 -o1 -o3 causes the substrings +matched by capturing parentheses 3 and 1 and then 3 again to be output. By +default, there is no separator (but see the next option). +</P> +<P> +<b>--om-separator</b>=<i>text</i> +Specify a separating string for multiple occurrences of <b>-o</b>. The default +is an empty string. Separating strings are never coloured. +</P> +<P> +<b>-q</b>, <b>--quiet</b> +Work quietly, that is, display nothing except error messages. The exit +status indicates whether or not any matches were found. +</P> +<P> +<b>-r</b>, <b>--recursive</b> +If any given path is a directory, recursively scan the files it contains, +taking note of any <b>--include</b> and <b>--exclude</b> settings. By default, a +directory is read as a normal file; in some operating systems this gives an +immediate end-of-file. This option is a shorthand for setting the <b>-d</b> +option to "recurse". +</P> +<P> +<b>--recursion-limit</b>=<i>number</i> +See <b>--match-limit</b> above. +</P> +<P> +<b>-s</b>, <b>--no-messages</b> +Suppress error messages about non-existent or unreadable files. Such files are +quietly skipped. However, the return code is still 2, even if matches were +found in other files. +</P> +<P> +<b>-u</b>, <b>--utf-8</b> +Operate in UTF-8 mode. This option is available only if PCRE has been compiled +with UTF-8 support. All patterns (including those for any <b>--exclude</b> and +<b>--include</b> options) and all subject lines that are scanned must be valid +strings of UTF-8 characters. +</P> +<P> +<b>-V</b>, <b>--version</b> +Write the version numbers of <b>pcregrep</b> and the PCRE library to the +standard output and then exit. Anything else on the command line is +ignored. +</P> +<P> +<b>-v</b>, <b>--invert-match</b> +Invert the sense of the match, so that lines which do <i>not</i> match any of +the patterns are the ones that are found. +</P> +<P> +<b>-w</b>, <b>--word-regex</b>, <b>--word-regexp</b> +Force the patterns to match only whole words. This is equivalent to having \b +at the start and end of the pattern. This option applies only to the patterns +that are matched against the contents of files; it does not apply to patterns +specified by any of the <b>--include</b> or <b>--exclude</b> options. +</P> +<P> +<b>-x</b>, <b>--line-regex</b>, <b>--line-regexp</b> +Force the patterns to be anchored (each must start matching at the beginning of +a line) and in addition, require them to match entire lines. This is equivalent +to having ^ and $ characters at the start and end of each alternative branch in +every pattern. This option applies only to the patterns that are matched +against the contents of files; it does not apply to patterns specified by any +of the <b>--include</b> or <b>--exclude</b> options. +</P> +<br><a name="SEC6" href="#TOC1">ENVIRONMENT VARIABLES</a><br> +<P> +The environment variables <b>LC_ALL</b> and <b>LC_CTYPE</b> are examined, in that +order, for a locale. The first one that is set is used. This can be overridden +by the <b>--locale</b> option. If no locale is set, the PCRE library's default +(usually the "C" locale) is used. +</P> +<br><a name="SEC7" href="#TOC1">NEWLINES</a><br> +<P> +The <b>-N</b> (<b>--newline</b>) option allows <b>pcregrep</b> to scan files with +different newline conventions from the default. Any parts of the input files +that are written to the standard output are copied identically, with whatever +newline sequences they have in the input. However, the setting of this option +does not affect the interpretation of files specified by the <b>-f</b>, +<b>--exclude-from</b>, or <b>--include-from</b> options, which are assumed to use +the operating system's standard newline sequence, nor does it affect the way in +which <b>pcregrep</b> writes informational messages to the standard error and +output streams. For these it uses the string "\n" to indicate newlines, +relying on the C I/O library to convert this to an appropriate sequence. +</P> +<br><a name="SEC8" href="#TOC1">OPTIONS COMPATIBILITY</a><br> +<P> +Many of the short and long forms of <b>pcregrep</b>'s options are the same +as in the GNU <b>grep</b> program. Any long option of the form +<b>--xxx-regexp</b> (GNU terminology) is also available as <b>--xxx-regex</b> +(PCRE terminology). However, the <b>--file-list</b>, <b>--file-offsets</b>, +<b>--include-dir</b>, <b>--line-offsets</b>, <b>--locale</b>, <b>--match-limit</b>, +<b>-M</b>, <b>--multiline</b>, <b>-N</b>, <b>--newline</b>, <b>--om-separator</b>, +<b>--recursion-limit</b>, <b>-u</b>, and <b>--utf-8</b> options are specific to +<b>pcregrep</b>, as is the use of the <b>--only-matching</b> option with a +capturing parentheses number. +</P> +<P> +Although most of the common options work the same way, a few are different in +<b>pcregrep</b>. For example, the <b>--include</b> option's argument is a glob +for GNU <b>grep</b>, but a regular expression for <b>pcregrep</b>. If both the +<b>-c</b> and <b>-l</b> options are given, GNU grep lists only file names, +without counts, but <b>pcregrep</b> gives the counts. +</P> +<br><a name="SEC9" href="#TOC1">OPTIONS WITH DATA</a><br> +<P> +There are four different ways in which an option with data can be specified. +If a short form option is used, the data may follow immediately, or (with one +exception) in the next command line item. For example: +<pre> + -f/some/file + -f /some/file +</pre> +The exception is the <b>-o</b> option, which may appear with or without data. +Because of this, if data is present, it must follow immediately in the same +item, for example -o3. +</P> +<P> +If a long form option is used, the data may appear in the same command line +item, separated by an equals character, or (with two exceptions) it may appear +in the next command line item. For example: +<pre> + --file=/some/file + --file /some/file +</pre> +Note, however, that if you want to supply a file name beginning with ~ as data +in a shell command, and have the shell expand ~ to a home directory, you must +separate the file name from the option, because the shell does not treat ~ +specially unless it is at the start of an item. +</P> +<P> +The exceptions to the above are the <b>--colour</b> (or <b>--color</b>) and +<b>--only-matching</b> options, for which the data is optional. If one of these +options does have data, it must be given in the first form, using an equals +character. Otherwise <b>pcregrep</b> will assume that it has no data. +</P> +<br><a name="SEC10" href="#TOC1">MATCHING ERRORS</a><br> +<P> +It is possible to supply a regular expression that takes a very long time to +fail to match certain lines. Such patterns normally involve nested indefinite +repeats, for example: (a+)*\d when matched against a line of a's with no final +digit. The PCRE matching function has a resource limit that causes it to abort +in these circumstances. If this happens, <b>pcregrep</b> outputs an error +message and the line that caused the problem to the standard error stream. If +there are more than 20 such errors, <b>pcregrep</b> gives up. +</P> +<P> +The <b>--match-limit</b> option of <b>pcregrep</b> can be used to set the overall +resource limit; there is a second option called <b>--recursion-limit</b> that +sets a limit on the amount of memory (usually stack) that is used (see the +discussion of these options above). +</P> +<br><a name="SEC11" href="#TOC1">DIAGNOSTICS</a><br> +<P> +Exit status is 0 if any matches were found, 1 if no matches were found, and 2 +for syntax errors, overlong lines, non-existent or inaccessible files (even if +matches were found in other files) or too many matching errors. Using the +<b>-s</b> option to suppress error messages about inaccessible files does not +affect the return code. +</P> +<br><a name="SEC12" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcrepattern</b>(3), <b>pcresyntax</b>(3), <b>pcretest</b>(1). +</P> +<br><a name="SEC13" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC14" href="#TOC1">REVISION</a><br> +<P> +Last updated: 03 April 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrejit.html b/doc/html/pcrejit.html new file mode 100644 index 0000000..210f1da --- /dev/null +++ b/doc/html/pcrejit.html @@ -0,0 +1,452 @@ +<html> +<head> +<title>pcrejit specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrejit man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE JUST-IN-TIME COMPILER SUPPORT</a> +<li><a name="TOC2" href="#SEC2">8-BIT, 16-BIT AND 32-BIT SUPPORT</a> +<li><a name="TOC3" href="#SEC3">AVAILABILITY OF JIT SUPPORT</a> +<li><a name="TOC4" href="#SEC4">SIMPLE USE OF JIT</a> +<li><a name="TOC5" href="#SEC5">UNSUPPORTED OPTIONS AND PATTERN ITEMS</a> +<li><a name="TOC6" href="#SEC6">RETURN VALUES FROM JIT EXECUTION</a> +<li><a name="TOC7" href="#SEC7">SAVING AND RESTORING COMPILED PATTERNS</a> +<li><a name="TOC8" href="#SEC8">CONTROLLING THE JIT STACK</a> +<li><a name="TOC9" href="#SEC9">JIT STACK FAQ</a> +<li><a name="TOC10" href="#SEC10">EXAMPLE CODE</a> +<li><a name="TOC11" href="#SEC11">JIT FAST PATH API</a> +<li><a name="TOC12" href="#SEC12">SEE ALSO</a> +<li><a name="TOC13" href="#SEC13">AUTHOR</a> +<li><a name="TOC14" href="#SEC14">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">PCRE JUST-IN-TIME COMPILER SUPPORT</a><br> +<P> +Just-in-time compiling is a heavyweight optimization that can greatly speed up +pattern matching. However, it comes at the cost of extra processing before the +match is performed. Therefore, it is of most benefit when the same pattern is +going to be matched many times. This does not necessarily mean many calls of a +matching function; if the pattern is not anchored, matching attempts may take +place many times at various positions in the subject, even for a single call. +Therefore, if the subject string is very long, it may still pay to use JIT for +one-off matches. +</P> +<P> +JIT support applies only to the traditional Perl-compatible matching function. +It does not apply when the DFA matching function is being used. The code for +this support was written by Zoltan Herczeg. +</P> +<br><a name="SEC2" href="#TOC1">8-BIT, 16-BIT AND 32-BIT SUPPORT</a><br> +<P> +JIT support is available for all of the 8-bit, 16-bit and 32-bit PCRE +libraries. To keep this documentation simple, only the 8-bit interface is +described in what follows. If you are using the 16-bit library, substitute the +16-bit functions and 16-bit structures (for example, <i>pcre16_jit_stack</i> +instead of <i>pcre_jit_stack</i>). If you are using the 32-bit library, +substitute the 32-bit functions and 32-bit structures (for example, +<i>pcre32_jit_stack</i> instead of <i>pcre_jit_stack</i>). +</P> +<br><a name="SEC3" href="#TOC1">AVAILABILITY OF JIT SUPPORT</a><br> +<P> +JIT support is an optional feature of PCRE. The "configure" option --enable-jit +(or equivalent CMake option) must be set when PCRE is built if you want to use +JIT. The support is limited to the following hardware platforms: +<pre> + ARM v5, v7, and Thumb2 + Intel x86 32-bit and 64-bit + MIPS 32-bit + Power PC 32-bit and 64-bit + SPARC 32-bit (experimental) +</pre> +If --enable-jit is set on an unsupported platform, compilation fails. +</P> +<P> +A program that is linked with PCRE 8.20 or later can tell if JIT support is +available by calling <b>pcre_config()</b> with the PCRE_CONFIG_JIT option. The +result is 1 when JIT is available, and 0 otherwise. However, a simple program +does not need to check this in order to use JIT. The normal API is implemented +in a way that falls back to the interpretive code if JIT is not available. For +programs that need the best possible performance, there is also a "fast path" +API that is JIT-specific. +</P> +<P> +If your program may sometimes be linked with versions of PCRE that are older +than 8.20, but you want to use JIT when it is available, you can test +the values of PCRE_MAJOR and PCRE_MINOR, or the existence of a JIT macro such +as PCRE_CONFIG_JIT, for compile-time control of your code. +</P> +<br><a name="SEC4" href="#TOC1">SIMPLE USE OF JIT</a><br> +<P> +You have to do two things to make use of the JIT support in the simplest way: +<pre> + (1) Call <b>pcre_study()</b> with the PCRE_STUDY_JIT_COMPILE option for + each compiled pattern, and pass the resulting <b>pcre_extra</b> block to + <b>pcre_exec()</b>. + + (2) Use <b>pcre_free_study()</b> to free the <b>pcre_extra</b> block when it is + no longer needed, instead of just freeing it yourself. This ensures that + any JIT data is also freed. +</pre> +For a program that may be linked with pre-8.20 versions of PCRE, you can insert +<pre> + #ifndef PCRE_STUDY_JIT_COMPILE + #define PCRE_STUDY_JIT_COMPILE 0 + #endif +</pre> +so that no option is passed to <b>pcre_study()</b>, and then use something like +this to free the study data: +<pre> + #ifdef PCRE_CONFIG_JIT + pcre_free_study(study_ptr); + #else + pcre_free(study_ptr); + #endif +</pre> +PCRE_STUDY_JIT_COMPILE requests the JIT compiler to generate code for complete +matches. If you want to run partial matches using the PCRE_PARTIAL_HARD or +PCRE_PARTIAL_SOFT options of <b>pcre_exec()</b>, you should set one or both of +the following options in addition to, or instead of, PCRE_STUDY_JIT_COMPILE +when you call <b>pcre_study()</b>: +<pre> + PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE + PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE +</pre> +The JIT compiler generates different optimized code for each of the three +modes (normal, soft partial, hard partial). When <b>pcre_exec()</b> is called, +the appropriate code is run if it is available. Otherwise, the pattern is +matched using interpretive code. +</P> +<P> +In some circumstances you may need to call additional functions. These are +described in the section entitled +<a href="#stackcontrol">"Controlling the JIT stack"</a> +below. +</P> +<P> +If JIT support is not available, PCRE_STUDY_JIT_COMPILE etc. are ignored, and +no JIT data is created. Otherwise, the compiled pattern is passed to the JIT +compiler, which turns it into machine code that executes much faster than the +normal interpretive code. When <b>pcre_exec()</b> is passed a <b>pcre_extra</b> +block containing a pointer to JIT code of the appropriate mode (normal or +hard/soft partial), it obeys that code instead of running the interpreter. The +result is identical, but the compiled JIT code runs much faster. +</P> +<P> +There are some <b>pcre_exec()</b> options that are not supported for JIT +execution. There are also some pattern items that JIT cannot handle. Details +are given below. In both cases, execution automatically falls back to the +interpretive code. If you want to know whether JIT was actually used for a +particular match, you should arrange for a JIT callback function to be set up +as described in the section entitled +<a href="#stackcontrol">"Controlling the JIT stack"</a> +below, even if you do not need to supply a non-default JIT stack. Such a +callback function is called whenever JIT code is about to be obeyed. If the +execution options are not right for JIT execution, the callback function is not +obeyed. +</P> +<P> +If the JIT compiler finds an unsupported item, no JIT data is generated. You +can find out if JIT execution is available after studying a pattern by calling +<b>pcre_fullinfo()</b> with the PCRE_INFO_JIT option. A result of 1 means that +JIT compilation was successful. A result of 0 means that JIT support is not +available, or the pattern was not studied with PCRE_STUDY_JIT_COMPILE etc., or +the JIT compiler was not able to handle the pattern. +</P> +<P> +Once a pattern has been studied, with or without JIT, it can be used as many +times as you like for matching different subject strings. +</P> +<br><a name="SEC5" href="#TOC1">UNSUPPORTED OPTIONS AND PATTERN ITEMS</a><br> +<P> +The only <b>pcre_exec()</b> options that are supported for JIT execution are +PCRE_NO_UTF8_CHECK, PCRE_NO_UTF16_CHECK, PCRE_NO_UTF32_CHECK, PCRE_NOTBOL, +PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and +PCRE_PARTIAL_SOFT. +</P> +<P> +The only unsupported pattern items are \C (match a single data unit) when +running in a UTF mode, and a callout immediately before an assertion condition +in a conditional group. +</P> +<br><a name="SEC6" href="#TOC1">RETURN VALUES FROM JIT EXECUTION</a><br> +<P> +When a pattern is matched using JIT execution, the return values are the same +as those given by the interpretive <b>pcre_exec()</b> code, with the addition of +one new error code: PCRE_ERROR_JIT_STACKLIMIT. This means that the memory used +for the JIT stack was insufficient. See +<a href="#stackcontrol">"Controlling the JIT stack"</a> +below for a discussion of JIT stack usage. For compatibility with the +interpretive <b>pcre_exec()</b> code, no more than two-thirds of the +<i>ovector</i> argument is used for passing back captured substrings. +</P> +<P> +The error code PCRE_ERROR_MATCHLIMIT is returned by the JIT code if searching a +very large pattern tree goes on for too long, as it is in the same circumstance +when JIT is not used, but the details of exactly what is counted are not the +same. The PCRE_ERROR_RECURSIONLIMIT error code is never returned by JIT +execution. +</P> +<br><a name="SEC7" href="#TOC1">SAVING AND RESTORING COMPILED PATTERNS</a><br> +<P> +The code that is generated by the JIT compiler is architecture-specific, and is +also position dependent. For those reasons it cannot be saved (in a file or +database) and restored later like the bytecode and other data of a compiled +pattern. Saving and restoring compiled patterns is not something many people +do. More detail about this facility is given in the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation. It should be possible to run <b>pcre_study()</b> on a saved and +restored pattern, and thereby recreate the JIT data, but because JIT +compilation uses significant resources, it is probably not worth doing this; +you might as well recompile the original pattern. +<a name="stackcontrol"></a></P> +<br><a name="SEC8" href="#TOC1">CONTROLLING THE JIT STACK</a><br> +<P> +When the compiled JIT code runs, it needs a block of memory to use as a stack. +By default, it uses 32K on the machine stack. However, some large or +complicated patterns need more than this. The error PCRE_ERROR_JIT_STACKLIMIT +is given when there is not enough stack. Three functions are provided for +managing blocks of memory for use as JIT stacks. There is further discussion +about the use of JIT stacks in the section entitled +<a href="#stackcontrol">"JIT stack FAQ"</a> +below. +</P> +<P> +The <b>pcre_jit_stack_alloc()</b> function creates a JIT stack. Its arguments +are a starting size and a maximum size, and it returns a pointer to an opaque +structure of type <b>pcre_jit_stack</b>, or NULL if there is an error. The +<b>pcre_jit_stack_free()</b> function can be used to free a stack that is no +longer needed. (For the technically minded: the address space is allocated by +mmap or VirtualAlloc.) +</P> +<P> +JIT uses far less memory for recursion than the interpretive code, +and a maximum stack size of 512K to 1M should be more than enough for any +pattern. +</P> +<P> +The <b>pcre_assign_jit_stack()</b> function specifies which stack JIT code +should use. Its arguments are as follows: +<pre> + pcre_extra *extra + pcre_jit_callback callback + void *data +</pre> +The <i>extra</i> argument must be the result of studying a pattern with +PCRE_STUDY_JIT_COMPILE etc. There are three cases for the values of the other +two options: +<pre> + (1) If <i>callback</i> is NULL and <i>data</i> is NULL, an internal 32K block + on the machine stack is used. + + (2) If <i>callback</i> is NULL and <i>data</i> is not NULL, <i>data</i> must be + a valid JIT stack, the result of calling <b>pcre_jit_stack_alloc()</b>. + + (3) If <i>callback</i> is not NULL, it must point to a function that is + called with <i>data</i> as an argument at the start of matching, in + order to set up a JIT stack. If the return from the callback + function is NULL, the internal 32K stack is used; otherwise the + return value must be a valid JIT stack, the result of calling + <b>pcre_jit_stack_alloc()</b>. +</pre> +A callback function is obeyed whenever JIT code is about to be run; it is not +obeyed when <b>pcre_exec()</b> is called with options that are incompatible for +JIT execution. A callback function can therefore be used to determine whether a +match operation was executed by JIT or by the interpreter. +</P> +<P> +You may safely use the same JIT stack for more than one pattern (either by +assigning directly or by callback), as long as the patterns are all matched +sequentially in the same thread. In a multithread application, if you do not +specify a JIT stack, or if you assign or pass back NULL from a callback, that +is thread-safe, because each thread has its own machine stack. However, if you +assign or pass back a non-NULL JIT stack, this must be a different stack for +each thread so that the application is thread-safe. +</P> +<P> +Strictly speaking, even more is allowed. You can assign the same non-NULL stack +to any number of patterns as long as they are not used for matching by multiple +threads at the same time. For example, you can assign the same stack to all +compiled patterns, and use a global mutex in the callback to wait until the +stack is available for use. However, this is an inefficient solution, and not +recommended. +</P> +<P> +This is a suggestion for how a multithreaded program that needs to set up +non-default JIT stacks might operate: +<pre> + During thread initalization + thread_local_var = pcre_jit_stack_alloc(...) + + During thread exit + pcre_jit_stack_free(thread_local_var) + + Use a one-line callback function + return thread_local_var +</pre> +All the functions described in this section do nothing if JIT is not available, +and <b>pcre_assign_jit_stack()</b> does nothing unless the <b>extra</b> argument +is non-NULL and points to a <b>pcre_extra</b> block that is the result of a +successful study with PCRE_STUDY_JIT_COMPILE etc. +<a name="stackfaq"></a></P> +<br><a name="SEC9" href="#TOC1">JIT STACK FAQ</a><br> +<P> +(1) Why do we need JIT stacks? +<br> +<br> +PCRE (and JIT) is a recursive, depth-first engine, so it needs a stack where +the local data of the current node is pushed before checking its child nodes. +Allocating real machine stack on some platforms is difficult. For example, the +stack chain needs to be updated every time if we extend the stack on PowerPC. +Although it is possible, its updating time overhead decreases performance. So +we do the recursion in memory. +</P> +<P> +(2) Why don't we simply allocate blocks of memory with <b>malloc()</b>? +<br> +<br> +Modern operating systems have a nice feature: they can reserve an address space +instead of allocating memory. We can safely allocate memory pages inside this +address space, so the stack could grow without moving memory data (this is +important because of pointers). Thus we can allocate 1M address space, and use +only a single memory page (usually 4K) if that is enough. However, we can still +grow up to 1M anytime if needed. +</P> +<P> +(3) Who "owns" a JIT stack? +<br> +<br> +The owner of the stack is the user program, not the JIT studied pattern or +anything else. The user program must ensure that if a stack is used by +<b>pcre_exec()</b>, (that is, it is assigned to the pattern currently running), +that stack must not be used by any other threads (to avoid overwriting the same +memory area). The best practice for multithreaded programs is to allocate a +stack for each thread, and return this stack through the JIT callback function. +</P> +<P> +(4) When should a JIT stack be freed? +<br> +<br> +You can free a JIT stack at any time, as long as it will not be used by +<b>pcre_exec()</b> again. When you assign the stack to a pattern, only a pointer +is set. There is no reference counting or any other magic. You can free the +patterns and stacks in any order, anytime. Just <i>do not</i> call +<b>pcre_exec()</b> with a pattern pointing to an already freed stack, as that +will cause SEGFAULT. (Also, do not free a stack currently used by +<b>pcre_exec()</b> in another thread). You can also replace the stack for a +pattern at any time. You can even free the previous stack before assigning a +replacement. +</P> +<P> +(5) Should I allocate/free a stack every time before/after calling +<b>pcre_exec()</b>? +<br> +<br> +No, because this is too costly in terms of resources. However, you could +implement some clever idea which release the stack if it is not used in let's +say two minutes. The JIT callback can help to achieve this without keeping a +list of the currently JIT studied patterns. +</P> +<P> +(6) OK, the stack is for long term memory allocation. But what happens if a +pattern causes stack overflow with a stack of 1M? Is that 1M kept until the +stack is freed? +<br> +<br> +Especially on embedded sytems, it might be a good idea to release memory +sometimes without freeing the stack. There is no API for this at the moment. +Probably a function call which returns with the currently allocated memory for +any stack and another which allows releasing memory (shrinking the stack) would +be a good idea if someone needs this. +</P> +<P> +(7) This is too much of a headache. Isn't there any better solution for JIT +stack handling? +<br> +<br> +No, thanks to Windows. If POSIX threads were used everywhere, we could throw +out this complicated API. +</P> +<br><a name="SEC10" href="#TOC1">EXAMPLE CODE</a><br> +<P> +This is a single-threaded example that specifies a JIT stack without using a +callback. +<pre> + int rc; + int ovector[30]; + pcre *re; + pcre_extra *extra; + pcre_jit_stack *jit_stack; + + re = pcre_compile(pattern, 0, &error, &erroffset, NULL); + /* Check for errors */ + extra = pcre_study(re, PCRE_STUDY_JIT_COMPILE, &error); + jit_stack = pcre_jit_stack_alloc(32*1024, 512*1024); + /* Check for error (NULL) */ + pcre_assign_jit_stack(extra, NULL, jit_stack); + rc = pcre_exec(re, extra, subject, length, 0, 0, ovector, 30); + /* Check results */ + pcre_free(re); + pcre_free_study(extra); + pcre_jit_stack_free(jit_stack); + +</PRE> +</P> +<br><a name="SEC11" href="#TOC1">JIT FAST PATH API</a><br> +<P> +Because the API described above falls back to interpreted execution when JIT is +not available, it is convenient for programs that are written for general use +in many environments. However, calling JIT via <b>pcre_exec()</b> does have a +performance impact. Programs that are written for use where JIT is known to be +available, and which need the best possible performance, can instead use a +"fast path" API to call JIT execution directly instead of calling +<b>pcre_exec()</b> (obviously only for patterns that have been successfully +studied by JIT). +</P> +<P> +The fast path function is called <b>pcre_jit_exec()</b>, and it takes exactly +the same arguments as <b>pcre_exec()</b>, plus one additional argument that +must point to a JIT stack. The JIT stack arrangements described above do not +apply. The return values are the same as for <b>pcre_exec()</b>. +</P> +<P> +When you call <b>pcre_exec()</b>, as well as testing for invalid options, a +number of other sanity checks are performed on the arguments. For example, if +the subject pointer is NULL, or its length is negative, an immediate error is +given. Also, unless PCRE_NO_UTF[8|16|32] is set, a UTF subject string is tested +for validity. In the interests of speed, these checks do not happen on the JIT +fast path, and if invalid data is passed, the result is undefined. +</P> +<P> +Bypassing the sanity checks and the <b>pcre_exec()</b> wrapping can give +speedups of more than 10%. +</P> +<br><a name="SEC12" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcreapi</b>(3) +</P> +<br><a name="SEC13" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel (FAQ by Zoltan Herczeg) +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC14" href="#TOC1">REVISION</a><br> +<P> +Last updated: 17 March 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrelimits.html b/doc/html/pcrelimits.html new file mode 100644 index 0000000..ee5ebf0 --- /dev/null +++ b/doc/html/pcrelimits.html @@ -0,0 +1,90 @@ +<html> +<head> +<title>pcrelimits specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrelimits man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +SIZE AND OTHER LIMITATIONS +</b><br> +<P> +There are some size limitations in PCRE but it is hoped that they will never in +practice be relevant. +</P> +<P> +The maximum length of a compiled pattern is approximately 64K data units (bytes +for the 8-bit library, 16-bit units for the 16-bit library, and 32-bit units for +the 32-bit library) if PCRE is compiled with the default internal linkage size, +which is 2 bytes for the 8-bit and 16-bit libraries, and 4 bytes for the 32-bit +library. If you want to process regular expressions that are truly enormous, +you can compile PCRE with an internal linkage size of 3 or 4 (when building the +16-bit or 32-bit library, 3 is rounded up to 4). See the <b>README</b> file in +the source distribution and the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation for details. In these cases the limit is substantially larger. +However, the speed of execution is slower. +</P> +<P> +All values in repeating quantifiers must be less than 65536. +</P> +<P> +There is no limit to the number of parenthesized subpatterns, but there can be +no more than 65535 capturing subpatterns. There is, however, a limit to the +depth of nesting of parenthesized subpatterns of all kinds. This is imposed in +order to limit the amount of system stack used at compile time. The limit can +be specified when PCRE is built; the default is 250. +</P> +<P> +There is a limit to the number of forward references to subsequent subpatterns +of around 200,000. Repeated forward references with fixed upper limits, for +example, (?2){0,100} when subpattern number 2 is to the right, are included in +the count. There is no limit to the number of backward references. +</P> +<P> +The maximum length of name for a named subpattern is 32 characters, and the +maximum number of named subpatterns is 10000. +</P> +<P> +The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb +is 255 for the 8-bit library and 65535 for the 16-bit and 32-bit libraries. +</P> +<P> +The maximum length of a subject string is the largest positive number that an +integer variable can hold. However, when using the traditional matching +function, PCRE uses recursion to handle subpatterns and indefinite repetition. +This means that the available stack space may limit the size of a subject +string that can be processed by certain patterns. For a discussion of stack +issues, see the +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 05 November 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrematching.html b/doc/html/pcrematching.html new file mode 100644 index 0000000..a1af39b --- /dev/null +++ b/doc/html/pcrematching.html @@ -0,0 +1,242 @@ +<html> +<head> +<title>pcrematching specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrematching man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE MATCHING ALGORITHMS</a> +<li><a name="TOC2" href="#SEC2">REGULAR EXPRESSIONS AS TREES</a> +<li><a name="TOC3" href="#SEC3">THE STANDARD MATCHING ALGORITHM</a> +<li><a name="TOC4" href="#SEC4">THE ALTERNATIVE MATCHING ALGORITHM</a> +<li><a name="TOC5" href="#SEC5">ADVANTAGES OF THE ALTERNATIVE ALGORITHM</a> +<li><a name="TOC6" href="#SEC6">DISADVANTAGES OF THE ALTERNATIVE ALGORITHM</a> +<li><a name="TOC7" href="#SEC7">AUTHOR</a> +<li><a name="TOC8" href="#SEC8">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">PCRE MATCHING ALGORITHMS</a><br> +<P> +This document describes the two different algorithms that are available in PCRE +for matching a compiled regular expression against a given subject string. The +"standard" algorithm is the one provided by the <b>pcre_exec()</b>, +<b>pcre16_exec()</b> and <b>pcre32_exec()</b> functions. These work in the same +as as Perl's matching function, and provide a Perl-compatible matching operation. +The just-in-time (JIT) optimization that is described in the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation is compatible with these functions. +</P> +<P> +An alternative algorithm is provided by the <b>pcre_dfa_exec()</b>, +<b>pcre16_dfa_exec()</b> and <b>pcre32_dfa_exec()</b> functions; they operate in +a different way, and are not Perl-compatible. This alternative has advantages +and disadvantages compared with the standard algorithm, and these are described +below. +</P> +<P> +When there is only one possible way in which a given subject string can match a +pattern, the two algorithms give the same answer. A difference arises, however, +when there are multiple possibilities. For example, if the pattern +<pre> + ^<.*> +</pre> +is matched against the string +<pre> + <something> <something else> <something further> +</pre> +there are three possible answers. The standard algorithm finds only one of +them, whereas the alternative algorithm finds all three. +</P> +<br><a name="SEC2" href="#TOC1">REGULAR EXPRESSIONS AS TREES</a><br> +<P> +The set of strings that are matched by a regular expression can be represented +as a tree structure. An unlimited repetition in the pattern makes the tree of +infinite size, but it is still a tree. Matching the pattern to a given subject +string (from a given starting point) can be thought of as a search of the tree. +There are two ways to search a tree: depth-first and breadth-first, and these +correspond to the two matching algorithms provided by PCRE. +</P> +<br><a name="SEC3" href="#TOC1">THE STANDARD MATCHING ALGORITHM</a><br> +<P> +In the terminology of Jeffrey Friedl's book "Mastering Regular +Expressions", the standard algorithm is an "NFA algorithm". It conducts a +depth-first search of the pattern tree. That is, it proceeds along a single +path through the tree, checking that the subject matches what is required. When +there is a mismatch, the algorithm tries any alternatives at the current point, +and if they all fail, it backs up to the previous branch point in the tree, and +tries the next alternative branch at that level. This often involves backing up +(moving to the left) in the subject string as well. The order in which +repetition branches are tried is controlled by the greedy or ungreedy nature of +the quantifier. +</P> +<P> +If a leaf node is reached, a matching string has been found, and at that point +the algorithm stops. Thus, if there is more than one possible match, this +algorithm returns the first one that it finds. Whether this is the shortest, +the longest, or some intermediate length depends on the way the greedy and +ungreedy repetition quantifiers are specified in the pattern. +</P> +<P> +Because it ends up with a single path through the tree, it is relatively +straightforward for this algorithm to keep track of the substrings that are +matched by portions of the pattern in parentheses. This provides support for +capturing parentheses and back references. +</P> +<br><a name="SEC4" href="#TOC1">THE ALTERNATIVE MATCHING ALGORITHM</a><br> +<P> +This algorithm conducts a breadth-first search of the tree. Starting from the +first matching point in the subject, it scans the subject string from left to +right, once, character by character, and as it does this, it remembers all the +paths through the tree that represent valid matches. In Friedl's terminology, +this is a kind of "DFA algorithm", though it is not implemented as a +traditional finite state machine (it keeps multiple states active +simultaneously). +</P> +<P> +Although the general principle of this matching algorithm is that it scans the +subject string only once, without backtracking, there is one exception: when a +lookaround assertion is encountered, the characters following or preceding the +current point have to be independently inspected. +</P> +<P> +The scan continues until either the end of the subject is reached, or there are +no more unterminated paths. At this point, terminated paths represent the +different matching possibilities (if there are none, the match has failed). +Thus, if there is more than one possible match, this algorithm finds all of +them, and in particular, it finds the longest. The matches are returned in +decreasing order of length. There is an option to stop the algorithm after the +first match (which is necessarily the shortest) is found. +</P> +<P> +Note that all the matches that are found start at the same point in the +subject. If the pattern +<pre> + cat(er(pillar)?)? +</pre> +is matched against the string "the caterpillar catchment", the result will be +the three strings "caterpillar", "cater", and "cat" that start at the fifth +character of the subject. The algorithm does not automatically move on to find +matches that start at later positions. +</P> +<P> +PCRE's "auto-possessification" optimization usually applies to character +repeats at the end of a pattern (as well as internally). For example, the +pattern "a\d+" is compiled as if it were "a\d++" because there is no point +even considering the possibility of backtracking into the repeated digits. For +DFA matching, this means that only one possible match is found. If you really +do want multiple matches in such cases, either use an ungreedy repeat +("a\d+?") or set the PCRE_NO_AUTO_POSSESS option when compiling. +</P> +<P> +There are a number of features of PCRE regular expressions that are not +supported by the alternative matching algorithm. They are as follows: +</P> +<P> +1. Because the algorithm finds all possible matches, the greedy or ungreedy +nature of repetition quantifiers is not relevant. Greedy and ungreedy +quantifiers are treated in exactly the same way. However, possessive +quantifiers can make a difference when what follows could also match what is +quantified, for example in a pattern like this: +<pre> + ^a++\w! +</pre> +This pattern matches "aaab!" but not "aaa!", which would be matched by a +non-possessive quantifier. Similarly, if an atomic group is present, it is +matched as if it were a standalone pattern at the current point, and the +longest match is then "locked in" for the rest of the overall pattern. +</P> +<P> +2. When dealing with multiple paths through the tree simultaneously, it is not +straightforward to keep track of captured substrings for the different matching +possibilities, and PCRE's implementation of this algorithm does not attempt to +do this. This means that no captured substrings are available. +</P> +<P> +3. Because no substrings are captured, back references within the pattern are +not supported, and cause errors if encountered. +</P> +<P> +4. For the same reason, conditional expressions that use a backreference as the +condition or test for a specific group recursion are not supported. +</P> +<P> +5. Because many paths through the tree may be active, the \K escape sequence, +which resets the start of the match when encountered (but may be on some paths +and not on others), is not supported. It causes an error if encountered. +</P> +<P> +6. Callouts are supported, but the value of the <i>capture_top</i> field is +always 1, and the value of the <i>capture_last</i> field is always -1. +</P> +<P> +7. The \C escape sequence, which (in the standard algorithm) always matches a +single data unit, even in UTF-8, UTF-16 or UTF-32 modes, is not supported in +these modes, because the alternative algorithm moves through the subject string +one character (not data unit) at a time, for all active paths through the tree. +</P> +<P> +8. Except for (*FAIL), the backtracking control verbs such as (*PRUNE) are not +supported. (*FAIL) is supported, and behaves like a failing negative assertion. +</P> +<br><a name="SEC5" href="#TOC1">ADVANTAGES OF THE ALTERNATIVE ALGORITHM</a><br> +<P> +Using the alternative matching algorithm provides the following advantages: +</P> +<P> +1. All possible matches (at a single point in the subject) are automatically +found, and in particular, the longest match is found. To find more than one +match using the standard algorithm, you have to do kludgy things with +callouts. +</P> +<P> +2. Because the alternative algorithm scans the subject string just once, and +never needs to backtrack (except for lookbehinds), it is possible to pass very +long subject strings to the matching function in several pieces, checking for +partial matching each time. Although it is possible to do multi-segment +matching using the standard algorithm by retaining partially matched +substrings, it is more complicated. The +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation gives details of partial matching and discusses multi-segment +matching. +</P> +<br><a name="SEC6" href="#TOC1">DISADVANTAGES OF THE ALTERNATIVE ALGORITHM</a><br> +<P> +The alternative algorithm suffers from a number of disadvantages: +</P> +<P> +1. It is substantially slower than the standard algorithm. This is partly +because it has to search for all possible matches, but is also because it is +less susceptible to optimization. +</P> +<P> +2. Capturing parentheses and back references are not supported. +</P> +<P> +3. Although atomic groups are supported, their use does not provide the +performance advantage that it does for the standard algorithm. +</P> +<br><a name="SEC7" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC8" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 November 2013 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrepartial.html b/doc/html/pcrepartial.html new file mode 100644 index 0000000..4faeafc --- /dev/null +++ b/doc/html/pcrepartial.html @@ -0,0 +1,509 @@ +<html> +<head> +<title>pcrepartial specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrepartial man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PARTIAL MATCHING IN PCRE</a> +<li><a name="TOC2" href="#SEC2">PARTIAL MATCHING USING pcre_exec() OR pcre[16|32]_exec()</a> +<li><a name="TOC3" href="#SEC3">PARTIAL MATCHING USING pcre_dfa_exec() OR pcre[16|32]_dfa_exec()</a> +<li><a name="TOC4" href="#SEC4">PARTIAL MATCHING AND WORD BOUNDARIES</a> +<li><a name="TOC5" href="#SEC5">FORMERLY RESTRICTED PATTERNS</a> +<li><a name="TOC6" href="#SEC6">EXAMPLE OF PARTIAL MATCHING USING PCRETEST</a> +<li><a name="TOC7" href="#SEC7">MULTI-SEGMENT MATCHING WITH pcre_dfa_exec() OR pcre[16|32]_dfa_exec()</a> +<li><a name="TOC8" href="#SEC8">MULTI-SEGMENT MATCHING WITH pcre_exec() OR pcre[16|32]_exec()</a> +<li><a name="TOC9" href="#SEC9">ISSUES WITH MULTI-SEGMENT MATCHING</a> +<li><a name="TOC10" href="#SEC10">AUTHOR</a> +<li><a name="TOC11" href="#SEC11">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">PARTIAL MATCHING IN PCRE</a><br> +<P> +In normal use of PCRE, if the subject string that is passed to a matching +function matches as far as it goes, but is too short to match the entire +pattern, PCRE_ERROR_NOMATCH is returned. There are circumstances where it might +be helpful to distinguish this case from other cases in which there is no +match. +</P> +<P> +Consider, for example, an application where a human is required to type in data +for a field with specific formatting requirements. An example might be a date +in the form <i>ddmmmyy</i>, defined by this pattern: +<pre> + ^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$ +</pre> +If the application sees the user's keystrokes one by one, and can check that +what has been typed so far is potentially valid, it is able to raise an error +as soon as a mistake is made, by beeping and not reflecting the character that +has been typed, for example. This immediate feedback is likely to be a better +user interface than a check that is delayed until the entire string has been +entered. Partial matching can also be useful when the subject string is very +long and is not all available at once. +</P> +<P> +PCRE supports partial matching by means of the PCRE_PARTIAL_SOFT and +PCRE_PARTIAL_HARD options, which can be set when calling any of the matching +functions. For backwards compatibility, PCRE_PARTIAL is a synonym for +PCRE_PARTIAL_SOFT. The essential difference between the two options is whether +or not a partial match is preferred to an alternative complete match, though +the details differ between the two types of matching function. If both options +are set, PCRE_PARTIAL_HARD takes precedence. +</P> +<P> +If you want to use partial matching with just-in-time optimized code, you must +call <b>pcre_study()</b>, <b>pcre16_study()</b> or <b>pcre32_study()</b> with one +or both of these options: +<pre> + PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE + PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE +</pre> +PCRE_STUDY_JIT_COMPILE should also be set if you are going to run non-partial +matches on the same pattern. If the appropriate JIT study mode has not been set +for a match, the interpretive matching code is used. +</P> +<P> +Setting a partial matching option disables two of PCRE's standard +optimizations. PCRE remembers the last literal data unit in a pattern, and +abandons matching immediately if it is not present in the subject string. This +optimization cannot be used for a subject string that might match only +partially. If the pattern was studied, PCRE knows the minimum length of a +matching string, and does not bother to run the matching function on shorter +strings. This optimization is also disabled for partial matching. +</P> +<br><a name="SEC2" href="#TOC1">PARTIAL MATCHING USING pcre_exec() OR pcre[16|32]_exec()</a><br> +<P> +A partial match occurs during a call to <b>pcre_exec()</b> or +<b>pcre[16|32]_exec()</b> when the end of the subject string is reached +successfully, but matching cannot continue because more characters are needed. +However, at least one character in the subject must have been inspected. This +character need not form part of the final matched string; lookbehind assertions +and the \K escape sequence provide ways of inspecting characters before the +start of a matched substring. The requirement for inspecting at least one +character exists because an empty string can always be matched; without such a +restriction there would always be a partial match of an empty string at the end +of the subject. +</P> +<P> +If there are at least two slots in the offsets vector when a partial match is +returned, the first slot is set to the offset of the earliest character that +was inspected. For convenience, the second offset points to the end of the +subject so that a substring can easily be identified. If there are at least +three slots in the offsets vector, the third slot is set to the offset of the +character where matching started. +</P> +<P> +For the majority of patterns, the contents of the first and third slots will be +the same. However, for patterns that contain lookbehind assertions, or begin +with \b or \B, characters before the one where matching started may have been +inspected while carrying out the match. For example, consider this pattern: +<pre> + /(?<=abc)123/ +</pre> +This pattern matches "123", but only if it is preceded by "abc". If the subject +string is "xyzabc12", the first two offsets after a partial match are for the +substring "abc12", because all these characters were inspected. However, the +third offset is set to 6, because that is the offset where matching began. +</P> +<P> +What happens when a partial match is identified depends on which of the two +partial matching options are set. +</P> +<br><b> +PCRE_PARTIAL_SOFT WITH pcre_exec() OR pcre[16|32]_exec() +</b><br> +<P> +If PCRE_PARTIAL_SOFT is set when <b>pcre_exec()</b> or <b>pcre[16|32]_exec()</b> +identifies a partial match, the partial match is remembered, but matching +continues as normal, and other alternatives in the pattern are tried. If no +complete match can be found, PCRE_ERROR_PARTIAL is returned instead of +PCRE_ERROR_NOMATCH. +</P> +<P> +This option is "soft" because it prefers a complete match over a partial match. +All the various matching items in a pattern behave as if the subject string is +potentially complete. For example, \z, \Z, and $ match at the end of the +subject, as normal, and for \b and \B the end of the subject is treated as a +non-alphanumeric. +</P> +<P> +If there is more than one partial match, the first one that was found provides +the data that is returned. Consider this pattern: +<pre> + /123\w+X|dogY/ +</pre> +If this is matched against the subject string "abc123dog", both +alternatives fail to match, but the end of the subject is reached during +matching, so PCRE_ERROR_PARTIAL is returned. The offsets are set to 3 and 9, +identifying "123dog" as the first partial match that was found. (In this +example, there are two partial matches, because "dog" on its own partially +matches the second alternative.) +</P> +<br><b> +PCRE_PARTIAL_HARD WITH pcre_exec() OR pcre[16|32]_exec() +</b><br> +<P> +If PCRE_PARTIAL_HARD is set for <b>pcre_exec()</b> or <b>pcre[16|32]_exec()</b>, +PCRE_ERROR_PARTIAL is returned as soon as a partial match is found, without +continuing to search for possible complete matches. This option is "hard" +because it prefers an earlier partial match over a later complete match. For +this reason, the assumption is made that the end of the supplied subject string +may not be the true end of the available data, and so, if \z, \Z, \b, \B, +or $ are encountered at the end of the subject, the result is +PCRE_ERROR_PARTIAL, provided that at least one character in the subject has +been inspected. +</P> +<P> +Setting PCRE_PARTIAL_HARD also affects the way UTF-8 and UTF-16 +subject strings are checked for validity. Normally, an invalid sequence +causes the error PCRE_ERROR_BADUTF8 or PCRE_ERROR_BADUTF16. However, in the +special case of a truncated character at the end of the subject, +PCRE_ERROR_SHORTUTF8 or PCRE_ERROR_SHORTUTF16 is returned when +PCRE_PARTIAL_HARD is set. +</P> +<br><b> +Comparing hard and soft partial matching +</b><br> +<P> +The difference between the two partial matching options can be illustrated by a +pattern such as: +<pre> + /dog(sbody)?/ +</pre> +This matches either "dog" or "dogsbody", greedily (that is, it prefers the +longer string if possible). If it is matched against the string "dog" with +PCRE_PARTIAL_SOFT, it yields a complete match for "dog". However, if +PCRE_PARTIAL_HARD is set, the result is PCRE_ERROR_PARTIAL. On the other hand, +if the pattern is made ungreedy the result is different: +<pre> + /dog(sbody)??/ +</pre> +In this case the result is always a complete match because that is found first, +and matching never continues after finding a complete match. It might be easier +to follow this explanation by thinking of the two patterns like this: +<pre> + /dog(sbody)?/ is the same as /dogsbody|dog/ + /dog(sbody)??/ is the same as /dog|dogsbody/ +</pre> +The second pattern will never match "dogsbody", because it will always find the +shorter match first. +</P> +<br><a name="SEC3" href="#TOC1">PARTIAL MATCHING USING pcre_dfa_exec() OR pcre[16|32]_dfa_exec()</a><br> +<P> +The DFA functions move along the subject string character by character, without +backtracking, searching for all possible matches simultaneously. If the end of +the subject is reached before the end of the pattern, there is the possibility +of a partial match, again provided that at least one character has been +inspected. +</P> +<P> +When PCRE_PARTIAL_SOFT is set, PCRE_ERROR_PARTIAL is returned only if there +have been no complete matches. Otherwise, the complete matches are returned. +However, if PCRE_PARTIAL_HARD is set, a partial match takes precedence over any +complete matches. The portion of the string that was inspected when the longest +partial match was found is set as the first matching string, provided there are +at least two slots in the offsets vector. +</P> +<P> +Because the DFA functions always search for all possible matches, and there is +no difference between greedy and ungreedy repetition, their behaviour is +different from the standard functions when PCRE_PARTIAL_HARD is set. Consider +the string "dog" matched against the ungreedy pattern shown above: +<pre> + /dog(sbody)??/ +</pre> +Whereas the standard functions stop as soon as they find the complete match for +"dog", the DFA functions also find the partial match for "dogsbody", and so +return that when PCRE_PARTIAL_HARD is set. +</P> +<br><a name="SEC4" href="#TOC1">PARTIAL MATCHING AND WORD BOUNDARIES</a><br> +<P> +If a pattern ends with one of sequences \b or \B, which test for word +boundaries, partial matching with PCRE_PARTIAL_SOFT can give counter-intuitive +results. Consider this pattern: +<pre> + /\bcat\b/ +</pre> +This matches "cat", provided there is a word boundary at either end. If the +subject string is "the cat", the comparison of the final "t" with a following +character cannot take place, so a partial match is found. However, normal +matching carries on, and \b matches at the end of the subject when the last +character is a letter, so a complete match is found. The result, therefore, is +<i>not</i> PCRE_ERROR_PARTIAL. Using PCRE_PARTIAL_HARD in this case does yield +PCRE_ERROR_PARTIAL, because then the partial match takes precedence. +</P> +<br><a name="SEC5" href="#TOC1">FORMERLY RESTRICTED PATTERNS</a><br> +<P> +For releases of PCRE prior to 8.00, because of the way certain internal +optimizations were implemented in the <b>pcre_exec()</b> function, the +PCRE_PARTIAL option (predecessor of PCRE_PARTIAL_SOFT) could not be used with +all patterns. From release 8.00 onwards, the restrictions no longer apply, and +partial matching with can be requested for any pattern. +</P> +<P> +Items that were formerly restricted were repeated single characters and +repeated metasequences. If PCRE_PARTIAL was set for a pattern that did not +conform to the restrictions, <b>pcre_exec()</b> returned the error code +PCRE_ERROR_BADPARTIAL (-13). This error code is no longer in use. The +PCRE_INFO_OKPARTIAL call to <b>pcre_fullinfo()</b> to find out if a compiled +pattern can be used for partial matching now always returns 1. +</P> +<br><a name="SEC6" href="#TOC1">EXAMPLE OF PARTIAL MATCHING USING PCRETEST</a><br> +<P> +If the escape sequence \P is present in a <b>pcretest</b> data line, the +PCRE_PARTIAL_SOFT option is used for the match. Here is a run of <b>pcretest</b> +that uses the date example quoted above: +<pre> + re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ + data> 25jun04\P + 0: 25jun04 + 1: jun + data> 25dec3\P + Partial match: 23dec3 + data> 3ju\P + Partial match: 3ju + data> 3juj\P + No match + data> j\P + No match +</pre> +The first data string is matched completely, so <b>pcretest</b> shows the +matched substrings. The remaining four strings do not match the complete +pattern, but the first two are partial matches. Similar output is obtained +if DFA matching is used. +</P> +<P> +If the escape sequence \P is present more than once in a <b>pcretest</b> data +line, the PCRE_PARTIAL_HARD option is set for the match. +</P> +<br><a name="SEC7" href="#TOC1">MULTI-SEGMENT MATCHING WITH pcre_dfa_exec() OR pcre[16|32]_dfa_exec()</a><br> +<P> +When a partial match has been found using a DFA matching function, it is +possible to continue the match by providing additional subject data and calling +the function again with the same compiled regular expression, this time setting +the PCRE_DFA_RESTART option. You must pass the same working space as before, +because this is where details of the previous partial match are stored. Here is +an example using <b>pcretest</b>, using the \R escape sequence to set the +PCRE_DFA_RESTART option (\D specifies the use of the DFA matching function): +<pre> + re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ + data> 23ja\P\D + Partial match: 23ja + data> n05\R\D + 0: n05 +</pre> +The first call has "23ja" as the subject, and requests partial matching; the +second call has "n05" as the subject for the continued (restarted) match. +Notice that when the match is complete, only the last part is shown; PCRE does +not retain the previously partially-matched string. It is up to the calling +program to do that if it needs to. +</P> +<P> +That means that, for an unanchored pattern, if a continued match fails, it is +not possible to try again at a new starting point. All this facility is capable +of doing is continuing with the previous match attempt. In the previous +example, if the second set of data is "ug23" the result is no match, even +though there would be a match for "aug23" if the entire string were given at +once. Depending on the application, this may or may not be what you want. +The only way to allow for starting again at the next character is to retain the +matched part of the subject and try a new complete match. +</P> +<P> +You can set the PCRE_PARTIAL_SOFT or PCRE_PARTIAL_HARD options with +PCRE_DFA_RESTART to continue partial matching over multiple segments. This +facility can be used to pass very long subject strings to the DFA matching +functions. +</P> +<br><a name="SEC8" href="#TOC1">MULTI-SEGMENT MATCHING WITH pcre_exec() OR pcre[16|32]_exec()</a><br> +<P> +From release 8.00, the standard matching functions can also be used to do +multi-segment matching. Unlike the DFA functions, it is not possible to +restart the previous match with a new segment of data. Instead, new data must +be added to the previous subject string, and the entire match re-run, starting +from the point where the partial match occurred. Earlier data can be discarded. +</P> +<P> +It is best to use PCRE_PARTIAL_HARD in this situation, because it does not +treat the end of a segment as the end of the subject when matching \z, \Z, +\b, \B, and $. Consider an unanchored pattern that matches dates: +<pre> + re> /\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d/ + data> The date is 23ja\P\P + Partial match: 23ja +</pre> +At this stage, an application could discard the text preceding "23ja", add on +text from the next segment, and call the matching function again. Unlike the +DFA matching functions, the entire matching string must always be available, +and the complete matching process occurs for each call, so more memory and more +processing time is needed. +</P> +<P> +<b>Note:</b> If the pattern contains lookbehind assertions, or \K, or starts +with \b or \B, the string that is returned for a partial match includes +characters that precede the start of what would be returned for a complete +match, because it contains all the characters that were inspected during the +partial match. +</P> +<br><a name="SEC9" href="#TOC1">ISSUES WITH MULTI-SEGMENT MATCHING</a><br> +<P> +Certain types of pattern may give problems with multi-segment matching, +whichever matching function is used. +</P> +<P> +1. If the pattern contains a test for the beginning of a line, you need to pass +the PCRE_NOTBOL option when the subject string for any call does start at the +beginning of a line. There is also a PCRE_NOTEOL option, but in practice when +doing multi-segment matching you should be using PCRE_PARTIAL_HARD, which +includes the effect of PCRE_NOTEOL. +</P> +<P> +2. Lookbehind assertions that have already been obeyed are catered for in the +offsets that are returned for a partial match. However a lookbehind assertion +later in the pattern could require even earlier characters to be inspected. You +can handle this case by using the PCRE_INFO_MAXLOOKBEHIND option of the +<b>pcre_fullinfo()</b> or <b>pcre[16|32]_fullinfo()</b> functions to obtain the +length of the longest lookbehind in the pattern. This length is given in +characters, not bytes. If you always retain at least that many characters +before the partially matched string, all should be well. (Of course, near the +start of the subject, fewer characters may be present; in that case all +characters should be retained.) +</P> +<P> +From release 8.33, there is a more accurate way of deciding which characters to +retain. Instead of subtracting the length of the longest lookbehind from the +earliest inspected character (<i>offsets[0]</i>), the match start position +(<i>offsets[2]</i>) should be used, and the next match attempt started at the +<i>offsets[2]</i> character by setting the <i>startoffset</i> argument of +<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. +</P> +<P> +For example, if the pattern "(?<=123)abc" is partially +matched against the string "xx123a", the three offset values returned are 2, 6, +and 5. This indicates that the matching process that gave a partial match +started at offset 5, but the characters "123a" were all inspected. The maximum +lookbehind for that pattern is 3, so taking that away from 5 shows that we need +only keep "123a", and the next match attempt can be started at offset 3 (that +is, at "a") when further characters have been added. When the match start is +not the earliest inspected character, <b>pcretest</b> shows it explicitly: +<pre> + re> "(?<=123)abc" + data> xx123a\P\P + Partial match at offset 5: 123a +</PRE> +</P> +<P> +3. Because a partial match must always contain at least one character, what +might be considered a partial match of an empty string actually gives a "no +match" result. For example: +<pre> + re> /c(?<=abc)x/ + data> ab\P + No match +</pre> +If the next segment begins "cx", a match should be found, but this will only +happen if characters from the previous segment are retained. For this reason, a +"no match" result should be interpreted as "partial match of an empty string" +when the pattern contains lookbehinds. +</P> +<P> +4. Matching a subject string that is split into multiple segments may not +always produce exactly the same result as matching over one single long string, +especially when PCRE_PARTIAL_SOFT is used. The section "Partial Matching and +Word Boundaries" above describes an issue that arises if the pattern ends with +\b or \B. Another kind of difference may occur when there are multiple +matching possibilities, because (for PCRE_PARTIAL_SOFT) a partial match result +is given only when there are no completed matches. This means that as soon as +the shortest match has been found, continuation to a new subject segment is no +longer possible. Consider again this <b>pcretest</b> example: +<pre> + re> /dog(sbody)?/ + data> dogsb\P + 0: dog + data> do\P\D + Partial match: do + data> gsb\R\P\D + 0: g + data> dogsbody\D + 0: dogsbody + 1: dog +</pre> +The first data line passes the string "dogsb" to a standard matching function, +setting the PCRE_PARTIAL_SOFT option. Although the string is a partial match +for "dogsbody", the result is not PCRE_ERROR_PARTIAL, because the shorter +string "dog" is a complete match. Similarly, when the subject is presented to +a DFA matching function in several parts ("do" and "gsb" being the first two) +the match stops when "dog" has been found, and it is not possible to continue. +On the other hand, if "dogsbody" is presented as a single string, a DFA +matching function finds both matches. +</P> +<P> +Because of these problems, it is best to use PCRE_PARTIAL_HARD when matching +multi-segment data. The example above then behaves differently: +<pre> + re> /dog(sbody)?/ + data> dogsb\P\P + Partial match: dogsb + data> do\P\D + Partial match: do + data> gsb\R\P\P\D + Partial match: gsb +</pre> +5. Patterns that contain alternatives at the top level which do not all start +with the same pattern item may not work as expected when PCRE_DFA_RESTART is +used. For example, consider this pattern: +<pre> + 1234|3789 +</pre> +If the first part of the subject is "ABC123", a partial match of the first +alternative is found at offset 3. There is no partial match for the second +alternative, because such a match does not start at the same point in the +subject string. Attempting to continue with the string "7890" does not yield a +match because only those alternatives that match at one point in the subject +are remembered. The problem arises because the start of the second alternative +matches within the first alternative. There is no problem with anchored +patterns or patterns such as: +<pre> + 1234|ABCD +</pre> +where no string can be a partial match for both alternatives. This is not a +problem if a standard matching function is used, because the entire match has +to be rerun each time: +<pre> + re> /1234|3789/ + data> ABC123\P\P + Partial match: 123 + data> 1237890 + 0: 3789 +</pre> +Of course, instead of using PCRE_DFA_RESTART, the same technique of re-running +the entire match can also be used with the DFA matching functions. Another +possibility is to work with two buffers. If a partial match at offset <i>n</i> +in the first buffer is followed by "no match" when PCRE_DFA_RESTART is used on +the second buffer, you can then try a new match starting at offset <i>n+1</i> in +the first buffer. +</P> +<br><a name="SEC10" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC11" href="#TOC1">REVISION</a><br> +<P> +Last updated: 02 July 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrepattern.html b/doc/html/pcrepattern.html new file mode 100644 index 0000000..c06d1e0 --- /dev/null +++ b/doc/html/pcrepattern.html @@ -0,0 +1,3235 @@ +<html> +<head> +<title>pcrepattern specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrepattern man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION DETAILS</a> +<li><a name="TOC2" href="#SEC2">SPECIAL START-OF-PATTERN ITEMS</a> +<li><a name="TOC3" href="#SEC3">EBCDIC CHARACTER CODES</a> +<li><a name="TOC4" href="#SEC4">CHARACTERS AND METACHARACTERS</a> +<li><a name="TOC5" href="#SEC5">BACKSLASH</a> +<li><a name="TOC6" href="#SEC6">CIRCUMFLEX AND DOLLAR</a> +<li><a name="TOC7" href="#SEC7">FULL STOP (PERIOD, DOT) AND \N</a> +<li><a name="TOC8" href="#SEC8">MATCHING A SINGLE DATA UNIT</a> +<li><a name="TOC9" href="#SEC9">SQUARE BRACKETS AND CHARACTER CLASSES</a> +<li><a name="TOC10" href="#SEC10">POSIX CHARACTER CLASSES</a> +<li><a name="TOC11" href="#SEC11">COMPATIBILITY FEATURE FOR WORD BOUNDARIES</a> +<li><a name="TOC12" href="#SEC12">VERTICAL BAR</a> +<li><a name="TOC13" href="#SEC13">INTERNAL OPTION SETTING</a> +<li><a name="TOC14" href="#SEC14">SUBPATTERNS</a> +<li><a name="TOC15" href="#SEC15">DUPLICATE SUBPATTERN NUMBERS</a> +<li><a name="TOC16" href="#SEC16">NAMED SUBPATTERNS</a> +<li><a name="TOC17" href="#SEC17">REPETITION</a> +<li><a name="TOC18" href="#SEC18">ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS</a> +<li><a name="TOC19" href="#SEC19">BACK REFERENCES</a> +<li><a name="TOC20" href="#SEC20">ASSERTIONS</a> +<li><a name="TOC21" href="#SEC21">CONDITIONAL SUBPATTERNS</a> +<li><a name="TOC22" href="#SEC22">COMMENTS</a> +<li><a name="TOC23" href="#SEC23">RECURSIVE PATTERNS</a> +<li><a name="TOC24" href="#SEC24">SUBPATTERNS AS SUBROUTINES</a> +<li><a name="TOC25" href="#SEC25">ONIGURUMA SUBROUTINE SYNTAX</a> +<li><a name="TOC26" href="#SEC26">CALLOUTS</a> +<li><a name="TOC27" href="#SEC27">BACKTRACKING CONTROL</a> +<li><a name="TOC28" href="#SEC28">SEE ALSO</a> +<li><a name="TOC29" href="#SEC29">AUTHOR</a> +<li><a name="TOC30" href="#SEC30">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION DETAILS</a><br> +<P> +The syntax and semantics of the regular expressions that are supported by PCRE +are described in detail below. There is a quick-reference syntax summary in the +<a href="pcresyntax.html"><b>pcresyntax</b></a> +page. PCRE tries to match Perl syntax and semantics as closely as it can. PCRE +also supports some alternative regular expression syntax (which does not +conflict with the Perl syntax) in order to provide some compatibility with +regular expressions in Python, .NET, and Oniguruma. +</P> +<P> +Perl's regular expressions are described in its own documentation, and +regular expressions in general are covered in a number of books, some of which +have copious examples. Jeffrey Friedl's "Mastering Regular Expressions", +published by O'Reilly, covers regular expressions in great detail. This +description of PCRE's regular expressions is intended as reference material. +</P> +<P> +This document discusses the patterns that are supported by PCRE when one its +main matching functions, <b>pcre_exec()</b> (8-bit) or <b>pcre[16|32]_exec()</b> +(16- or 32-bit), is used. PCRE also has alternative matching functions, +<b>pcre_dfa_exec()</b> and <b>pcre[16|32_dfa_exec()</b>, which match using a +different algorithm that is not Perl-compatible. Some of the features discussed +below are not available when DFA matching is used. The advantages and +disadvantages of the alternative functions, and how they differ from the normal +functions, are discussed in the +<a href="pcrematching.html"><b>pcrematching</b></a> +page. +</P> +<br><a name="SEC2" href="#TOC1">SPECIAL START-OF-PATTERN ITEMS</a><br> +<P> +A number of options that can be passed to <b>pcre_compile()</b> can also be set +by special items at the start of a pattern. These are not Perl-compatible, but +are provided to make these options accessible to pattern writers who are not +able to change the program that processes the pattern. Any number of these +items may appear, but they must all be together right at the start of the +pattern string, and the letters must be in upper case. +</P> +<br><b> +UTF support +</b><br> +<P> +The original operation of PCRE was on strings of one-byte characters. However, +there is now also support for UTF-8 strings in the original library, an +extra library that supports 16-bit and UTF-16 character strings, and a +third library that supports 32-bit and UTF-32 character strings. To use these +features, PCRE must be built to include appropriate support. When using UTF +strings you must either call the compiling function with the PCRE_UTF8, +PCRE_UTF16, or PCRE_UTF32 option, or the pattern must start with one of +these special sequences: +<pre> + (*UTF8) + (*UTF16) + (*UTF32) + (*UTF) +</pre> +(*UTF) is a generic sequence that can be used with any of the libraries. +Starting a pattern with such a sequence is equivalent to setting the relevant +option. How setting a UTF mode affects pattern matching is mentioned in several +places below. There is also a summary of features in the +<a href="pcreunicode.html"><b>pcreunicode</b></a> +page. +</P> +<P> +Some applications that allow their users to supply patterns may wish to +restrict them to non-UTF data for security reasons. If the PCRE_NEVER_UTF +option is set at compile time, (*UTF) etc. are not allowed, and their +appearance causes an error. +</P> +<br><b> +Unicode property support +</b><br> +<P> +Another special sequence that may appear at the start of a pattern is (*UCP). +This has the same effect as setting the PCRE_UCP option: it causes sequences +such as \d and \w to use Unicode properties to determine character types, +instead of recognizing only characters with codes less than 128 via a lookup +table. +</P> +<br><b> +Disabling auto-possessification +</b><br> +<P> +If a pattern starts with (*NO_AUTO_POSSESS), it has the same effect as setting +the PCRE_NO_AUTO_POSSESS option at compile time. This stops PCRE from making +quantifiers possessive when what follows cannot match the repeated item. For +example, by default a+b is treated as a++b. For more details, see the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<br><b> +Disabling start-up optimizations +</b><br> +<P> +If a pattern starts with (*NO_START_OPT), it has the same effect as setting the +PCRE_NO_START_OPTIMIZE option either at compile or matching time. This disables +several optimizations for quickly reaching "no match" results. For more +details, see the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +<a name="newlines"></a></P> +<br><b> +Newline conventions +</b><br> +<P> +PCRE supports five different conventions for indicating line breaks in +strings: a single CR (carriage return) character, a single LF (linefeed) +character, the two-character sequence CRLF, any of the three preceding, or any +Unicode newline sequence. The +<a href="pcreapi.html"><b>pcreapi</b></a> +page has +<a href="pcreapi.html#newlines">further discussion</a> +about newlines, and shows how to set the newline convention in the +<i>options</i> arguments for the compiling and matching functions. +</P> +<P> +It is also possible to specify a newline convention by starting a pattern +string with one of the following five sequences: +<pre> + (*CR) carriage return + (*LF) linefeed + (*CRLF) carriage return, followed by linefeed + (*ANYCRLF) any of the three above + (*ANY) all Unicode newline sequences +</pre> +These override the default and the options given to the compiling function. For +example, on a Unix system where LF is the default newline sequence, the pattern +<pre> + (*CR)a.b +</pre> +changes the convention to CR. That pattern matches "a\nb" because LF is no +longer a newline. If more than one of these settings is present, the last one +is used. +</P> +<P> +The newline convention affects where the circumflex and dollar assertions are +true. It also affects the interpretation of the dot metacharacter when +PCRE_DOTALL is not set, and the behaviour of \N. However, it does not affect +what the \R escape sequence matches. By default, this is any Unicode newline +sequence, for Perl compatibility. However, this can be changed; see the +description of \R in the section entitled +<a href="#newlineseq">"Newline sequences"</a> +below. A change of \R setting can be combined with a change of newline +convention. +</P> +<br><b> +Setting match and recursion limits +</b><br> +<P> +The caller of <b>pcre_exec()</b> can set a limit on the number of times the +internal <b>match()</b> function is called and on the maximum depth of +recursive calls. These facilities are provided to catch runaway matches that +are provoked by patterns with huge matching trees (a typical example is a +pattern with nested unlimited repeats) and to avoid running out of system stack +by too much recursion. When one of these limits is reached, <b>pcre_exec()</b> +gives an error return. The limits can also be set by items at the start of the +pattern of the form +<pre> + (*LIMIT_MATCH=d) + (*LIMIT_RECURSION=d) +</pre> +where d is any number of decimal digits. However, the value of the setting must +be less than the value set (or defaulted) by the caller of <b>pcre_exec()</b> +for it to have any effect. In other words, the pattern writer can lower the +limits set by the programmer, but not raise them. If there is more than one +setting of one of these limits, the lower value is used. +</P> +<br><a name="SEC3" href="#TOC1">EBCDIC CHARACTER CODES</a><br> +<P> +PCRE can be compiled to run in an environment that uses EBCDIC as its character +code rather than ASCII or Unicode (typically a mainframe system). In the +sections below, character code values are ASCII or Unicode; in an EBCDIC +environment these characters may have different code values, and there are no +code points greater than 255. +</P> +<br><a name="SEC4" href="#TOC1">CHARACTERS AND METACHARACTERS</a><br> +<P> +A regular expression is a pattern that is matched against a subject string from +left to right. Most characters stand for themselves in a pattern, and match the +corresponding characters in the subject. As a trivial example, the pattern +<pre> + The quick brown fox +</pre> +matches a portion of a subject string that is identical to itself. When +caseless matching is specified (the PCRE_CASELESS option), letters are matched +independently of case. In a UTF mode, PCRE always understands the concept of +case for characters whose values are less than 128, so caseless matching is +always possible. For characters with higher values, the concept of case is +supported if PCRE is compiled with Unicode property support, but not otherwise. +If you want to use caseless matching for characters 128 and above, you must +ensure that PCRE is compiled with Unicode property support as well as with +UTF support. +</P> +<P> +The power of regular expressions comes from the ability to include alternatives +and repetitions in the pattern. These are encoded in the pattern by the use of +<i>metacharacters</i>, which do not stand for themselves but instead are +interpreted in some special way. +</P> +<P> +There are two different sets of metacharacters: those that are recognized +anywhere in the pattern except within square brackets, and those that are +recognized within square brackets. Outside square brackets, the metacharacters +are as follows: +<pre> + \ general escape character with several uses + ^ assert start of string (or line, in multiline mode) + $ assert end of string (or line, in multiline mode) + . match any character except newline (by default) + [ start character class definition + | start of alternative branch + ( start subpattern + ) end subpattern + ? extends the meaning of ( + also 0 or 1 quantifier + also quantifier minimizer + * 0 or more quantifier + + 1 or more quantifier + also "possessive quantifier" + { start min/max quantifier +</pre> +Part of a pattern that is in square brackets is called a "character class". In +a character class the only metacharacters are: +<pre> + \ general escape character + ^ negate the class, but only if the first character + - indicates character range + [ POSIX character class (only if followed by POSIX syntax) + ] terminates the character class +</pre> +The following sections describe the use of each of the metacharacters. +</P> +<br><a name="SEC5" href="#TOC1">BACKSLASH</a><br> +<P> +The backslash character has several uses. Firstly, if it is followed by a +character that is not a number or a letter, it takes away any special meaning +that character may have. This use of backslash as an escape character applies +both inside and outside character classes. +</P> +<P> +For example, if you want to match a * character, you write \* in the pattern. +This escaping action applies whether or not the following character would +otherwise be interpreted as a metacharacter, so it is always safe to precede a +non-alphanumeric with backslash to specify that it stands for itself. In +particular, if you want to match a backslash, you write \\. +</P> +<P> +In a UTF mode, only ASCII numbers and letters have any special meaning after a +backslash. All other characters (in particular, those whose codepoints are +greater than 127) are treated as literals. +</P> +<P> +If a pattern is compiled with the PCRE_EXTENDED option, most white space in the +pattern (other than in a character class), and characters between a # outside a +character class and the next newline, inclusive, are ignored. An escaping +backslash can be used to include a white space or # character as part of the +pattern. +</P> +<P> +If you want to remove the special meaning from a sequence of characters, you +can do so by putting them between \Q and \E. This is different from Perl in +that $ and @ are handled as literals in \Q...\E sequences in PCRE, whereas in +Perl, $ and @ cause variable interpolation. Note the following examples: +<pre> + Pattern PCRE matches Perl matches + + \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz + \Qabc\$xyz\E abc\$xyz abc\$xyz + \Qabc\E\$\Qxyz\E abc$xyz abc$xyz +</pre> +The \Q...\E sequence is recognized both inside and outside character classes. +An isolated \E that is not preceded by \Q is ignored. If \Q is not followed +by \E later in the pattern, the literal interpretation continues to the end of +the pattern (that is, \E is assumed at the end). If the isolated \Q is inside +a character class, this causes an error, because the character class is not +terminated. +<a name="digitsafterbackslash"></a></P> +<br><b> +Non-printing characters +</b><br> +<P> +A second use of backslash provides a way of encoding non-printing characters +in patterns in a visible manner. There is no restriction on the appearance of +non-printing characters, apart from the binary zero that terminates a pattern, +but when a pattern is being prepared by text editing, it is often easier to use +one of the following escape sequences than the binary character it represents: +<pre> + \a alarm, that is, the BEL character (hex 07) + \cx "control-x", where x is any ASCII character + \e escape (hex 1B) + \f form feed (hex 0C) + \n linefeed (hex 0A) + \r carriage return (hex 0D) + \t tab (hex 09) + \0dd character with octal code 0dd + \ddd character with octal code ddd, or back reference + \o{ddd..} character with octal code ddd.. + \xhh character with hex code hh + \x{hhh..} character with hex code hhh.. (non-JavaScript mode) + \uhhhh character with hex code hhhh (JavaScript mode only) +</pre> +The precise effect of \cx on ASCII characters is as follows: if x is a lower +case letter, it is converted to upper case. Then bit 6 of the character (hex +40) is inverted. Thus \cA to \cZ become hex 01 to hex 1A (A is 41, Z is 5A), +but \c{ becomes hex 3B ({ is 7B), and \c; becomes hex 7B (; is 3B). If the +data item (byte or 16-bit value) following \c has a value greater than 127, a +compile-time error occurs. This locks out non-ASCII characters in all modes. +</P> +<P> +The \c facility was designed for use with ASCII characters, but with the +extension to Unicode it is even less useful than it once was. It is, however, +recognized when PCRE is compiled in EBCDIC mode, where data items are always +bytes. In this mode, all values are valid after \c. If the next character is a +lower case letter, it is converted to upper case. Then the 0xc0 bits of the +byte are inverted. Thus \cA becomes hex 01, as in ASCII (A is C1), but because +the EBCDIC letters are disjoint, \cZ becomes hex 29 (Z is E9), and other +characters also generate different values. +</P> +<P> +After \0 up to two further octal digits are read. If there are fewer than two +digits, just those that are present are used. Thus the sequence \0\x\07 +specifies two binary zeros followed by a BEL character (code value 7). Make +sure you supply two digits after the initial zero if the pattern character that +follows is itself an octal digit. +</P> +<P> +The escape \o must be followed by a sequence of octal digits, enclosed in +braces. An error occurs if this is not the case. This escape is a recent +addition to Perl; it provides way of specifying character code points as octal +numbers greater than 0777, and it also allows octal numbers and back references +to be unambiguously specified. +</P> +<P> +For greater clarity and unambiguity, it is best to avoid following \ by a +digit greater than zero. Instead, use \o{} or \x{} to specify character +numbers, and \g{} to specify back references. The following paragraphs +describe the old, ambiguous syntax. +</P> +<P> +The handling of a backslash followed by a digit other than 0 is complicated, +and Perl has changed in recent releases, causing PCRE also to change. Outside a +character class, PCRE reads the digit and any following digits as a decimal +number. If the number is less than 8, or if there have been at least that many +previous capturing left parentheses in the expression, the entire sequence is +taken as a <i>back reference</i>. A description of how this works is given +<a href="#backreferences">later,</a> +following the discussion of +<a href="#subpattern">parenthesized subpatterns.</a> +</P> +<P> +Inside a character class, or if the decimal number following \ is greater than +7 and there have not been that many capturing subpatterns, PCRE handles \8 and +\9 as the literal characters "8" and "9", and otherwise re-reads up to three +octal digits following the backslash, using them to generate a data character. +Any subsequent digits stand for themselves. For example: +<pre> + \040 is another way of writing an ASCII space + \40 is the same, provided there are fewer than 40 previous capturing subpatterns + \7 is always a back reference + \11 might be a back reference, or another way of writing a tab + \011 is always a tab + \0113 is a tab followed by the character "3" + \113 might be a back reference, otherwise the character with octal code 113 + \377 might be a back reference, otherwise the value 255 (decimal) + \81 is either a back reference, or the two characters "8" and "1" +</pre> +Note that octal values of 100 or greater that are specified using this syntax +must not be introduced by a leading zero, because no more than three octal +digits are ever read. +</P> +<P> +By default, after \x that is not followed by {, from zero to two hexadecimal +digits are read (letters can be in upper or lower case). Any number of +hexadecimal digits may appear between \x{ and }. If a character other than +a hexadecimal digit appears between \x{ and }, or if there is no terminating +}, an error occurs. +</P> +<P> +If the PCRE_JAVASCRIPT_COMPAT option is set, the interpretation of \x is +as just described only when it is followed by two hexadecimal digits. +Otherwise, it matches a literal "x" character. In JavaScript mode, support for +code points greater than 256 is provided by \u, which must be followed by +four hexadecimal digits; otherwise it matches a literal "u" character. +</P> +<P> +Characters whose value is less than 256 can be defined by either of the two +syntaxes for \x (or by \u in JavaScript mode). There is no difference in the +way they are handled. For example, \xdc is exactly the same as \x{dc} (or +\u00dc in JavaScript mode). +</P> +<br><b> +Constraints on character values +</b><br> +<P> +Characters that are specified using octal or hexadecimal numbers are +limited to certain values, as follows: +<pre> + 8-bit non-UTF mode less than 0x100 + 8-bit UTF-8 mode less than 0x10ffff and a valid codepoint + 16-bit non-UTF mode less than 0x10000 + 16-bit UTF-16 mode less than 0x10ffff and a valid codepoint + 32-bit non-UTF mode less than 0x100000000 + 32-bit UTF-32 mode less than 0x10ffff and a valid codepoint +</pre> +Invalid Unicode codepoints are the range 0xd800 to 0xdfff (the so-called +"surrogate" codepoints), and 0xffef. +</P> +<br><b> +Escape sequences in character classes +</b><br> +<P> +All the sequences that define a single character value can be used both inside +and outside character classes. In addition, inside a character class, \b is +interpreted as the backspace character (hex 08). +</P> +<P> +\N is not allowed in a character class. \B, \R, and \X are not special +inside a character class. Like other unrecognized escape sequences, they are +treated as the literal characters "B", "R", and "X" by default, but cause an +error if the PCRE_EXTRA option is set. Outside a character class, these +sequences have different meanings. +</P> +<br><b> +Unsupported escape sequences +</b><br> +<P> +In Perl, the sequences \l, \L, \u, and \U are recognized by its string +handler and used to modify the case of following characters. By default, PCRE +does not support these escape sequences. However, if the PCRE_JAVASCRIPT_COMPAT +option is set, \U matches a "U" character, and \u can be used to define a +character by code point, as described in the previous section. +</P> +<br><b> +Absolute and relative back references +</b><br> +<P> +The sequence \g followed by an unsigned or a negative number, optionally +enclosed in braces, is an absolute or relative back reference. A named back +reference can be coded as \g{name}. Back references are discussed +<a href="#backreferences">later,</a> +following the discussion of +<a href="#subpattern">parenthesized subpatterns.</a> +</P> +<br><b> +Absolute and relative subroutine calls +</b><br> +<P> +For compatibility with Oniguruma, the non-Perl syntax \g followed by a name or +a number enclosed either in angle brackets or single quotes, is an alternative +syntax for referencing a subpattern as a "subroutine". Details are discussed +<a href="#onigurumasubroutines">later.</a> +Note that \g{...} (Perl syntax) and \g<...> (Oniguruma syntax) are <i>not</i> +synonymous. The former is a back reference; the latter is a +<a href="#subpatternsassubroutines">subroutine</a> +call. +<a name="genericchartypes"></a></P> +<br><b> +Generic character types +</b><br> +<P> +Another use of backslash is for specifying generic character types: +<pre> + \d any decimal digit + \D any character that is not a decimal digit + \h any horizontal white space character + \H any character that is not a horizontal white space character + \s any white space character + \S any character that is not a white space character + \v any vertical white space character + \V any character that is not a vertical white space character + \w any "word" character + \W any "non-word" character +</pre> +There is also the single sequence \N, which matches a non-newline character. +This is the same as +<a href="#fullstopdot">the "." metacharacter</a> +when PCRE_DOTALL is not set. Perl also uses \N to match characters by name; +PCRE does not support this. +</P> +<P> +Each pair of lower and upper case escape sequences partitions the complete set +of characters into two disjoint sets. Any given character matches one, and only +one, of each pair. The sequences can appear both inside and outside character +classes. They each match one character of the appropriate type. If the current +matching point is at the end of the subject string, all of them fail, because +there is no character to match. +</P> +<P> +For compatibility with Perl, \s did not used to match the VT character (code +11), which made it different from the the POSIX "space" class. However, Perl +added VT at release 5.18, and PCRE followed suit at release 8.34. The default +\s characters are now HT (9), LF (10), VT (11), FF (12), CR (13), and space +(32), which are defined as white space in the "C" locale. This list may vary if +locale-specific matching is taking place. For example, in some locales the +"non-breaking space" character (\xA0) is recognized as white space, and in +others the VT character is not. +</P> +<P> +A "word" character is an underscore or any character that is a letter or digit. +By default, the definition of letters and digits is controlled by PCRE's +low-valued character tables, and may vary if locale-specific matching is taking +place (see +<a href="pcreapi.html#localesupport">"Locale support"</a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page). For example, in a French locale such as "fr_FR" in Unix-like systems, +or "french" in Windows, some character codes greater than 127 are used for +accented letters, and these are then matched by \w. The use of locales with +Unicode is discouraged. +</P> +<P> +By default, characters whose code points are greater than 127 never match \d, +\s, or \w, and always match \D, \S, and \W, although this may vary for +characters in the range 128-255 when locale-specific matching is happening. +These escape sequences retain their original meanings from before Unicode +support was available, mainly for efficiency reasons. If PCRE is compiled with +Unicode property support, and the PCRE_UCP option is set, the behaviour is +changed so that Unicode properties are used to determine character types, as +follows: +<pre> + \d any character that matches \p{Nd} (decimal digit) + \s any character that matches \p{Z} or \h or \v + \w any character that matches \p{L} or \p{N}, plus underscore +</pre> +The upper case escapes match the inverse sets of characters. Note that \d +matches only decimal digits, whereas \w matches any Unicode digit, as well as +any Unicode letter, and underscore. Note also that PCRE_UCP affects \b, and +\B because they are defined in terms of \w and \W. Matching these sequences +is noticeably slower when PCRE_UCP is set. +</P> +<P> +The sequences \h, \H, \v, and \V are features that were added to Perl at +release 5.10. In contrast to the other sequences, which match only ASCII +characters by default, these always match certain high-valued code points, +whether or not PCRE_UCP is set. The horizontal space characters are: +<pre> + U+0009 Horizontal tab (HT) + U+0020 Space + U+00A0 Non-break space + U+1680 Ogham space mark + U+180E Mongolian vowel separator + U+2000 En quad + U+2001 Em quad + U+2002 En space + U+2003 Em space + U+2004 Three-per-em space + U+2005 Four-per-em space + U+2006 Six-per-em space + U+2007 Figure space + U+2008 Punctuation space + U+2009 Thin space + U+200A Hair space + U+202F Narrow no-break space + U+205F Medium mathematical space + U+3000 Ideographic space +</pre> +The vertical space characters are: +<pre> + U+000A Linefeed (LF) + U+000B Vertical tab (VT) + U+000C Form feed (FF) + U+000D Carriage return (CR) + U+0085 Next line (NEL) + U+2028 Line separator + U+2029 Paragraph separator +</pre> +In 8-bit, non-UTF-8 mode, only the characters with codepoints less than 256 are +relevant. +<a name="newlineseq"></a></P> +<br><b> +Newline sequences +</b><br> +<P> +Outside a character class, by default, the escape sequence \R matches any +Unicode newline sequence. In 8-bit non-UTF-8 mode \R is equivalent to the +following: +<pre> + (?>\r\n|\n|\x0b|\f|\r|\x85) +</pre> +This is an example of an "atomic group", details of which are given +<a href="#atomicgroup">below.</a> +This particular group matches either the two-character sequence CR followed by +LF, or one of the single characters LF (linefeed, U+000A), VT (vertical tab, +U+000B), FF (form feed, U+000C), CR (carriage return, U+000D), or NEL (next +line, U+0085). The two-character sequence is treated as a single unit that +cannot be split. +</P> +<P> +In other modes, two additional characters whose codepoints are greater than 255 +are added: LS (line separator, U+2028) and PS (paragraph separator, U+2029). +Unicode character property support is not needed for these characters to be +recognized. +</P> +<P> +It is possible to restrict \R to match only CR, LF, or CRLF (instead of the +complete set of Unicode line endings) by setting the option PCRE_BSR_ANYCRLF +either at compile time or when the pattern is matched. (BSR is an abbrevation +for "backslash R".) This can be made the default when PCRE is built; if this is +the case, the other behaviour can be requested via the PCRE_BSR_UNICODE option. +It is also possible to specify these settings by starting a pattern string with +one of the following sequences: +<pre> + (*BSR_ANYCRLF) CR, LF, or CRLF only + (*BSR_UNICODE) any Unicode newline sequence +</pre> +These override the default and the options given to the compiling function, but +they can themselves be overridden by options given to a matching function. Note +that these special settings, which are not Perl-compatible, are recognized only +at the very start of a pattern, and that they must be in upper case. If more +than one of them is present, the last one is used. They can be combined with a +change of newline convention; for example, a pattern can start with: +<pre> + (*ANY)(*BSR_ANYCRLF) +</pre> +They can also be combined with the (*UTF8), (*UTF16), (*UTF32), (*UTF) or +(*UCP) special sequences. Inside a character class, \R is treated as an +unrecognized escape sequence, and so matches the letter "R" by default, but +causes an error if PCRE_EXTRA is set. +<a name="uniextseq"></a></P> +<br><b> +Unicode character properties +</b><br> +<P> +When PCRE is built with Unicode character property support, three additional +escape sequences that match characters with specific properties are available. +When in 8-bit non-UTF-8 mode, these sequences are of course limited to testing +characters whose codepoints are less than 256, but they do work in this mode. +The extra escape sequences are: +<pre> + \p{<i>xx</i>} a character with the <i>xx</i> property + \P{<i>xx</i>} a character without the <i>xx</i> property + \X a Unicode extended grapheme cluster +</pre> +The property names represented by <i>xx</i> above are limited to the Unicode +script names, the general category properties, "Any", which matches any +character (including newline), and some special PCRE properties (described +in the +<a href="#extraprops">next section).</a> +Other Perl properties such as "InMusicalSymbols" are not currently supported by +PCRE. Note that \P{Any} does not match any characters, so always causes a +match failure. +</P> +<P> +Sets of Unicode characters are defined as belonging to certain scripts. A +character from one of these sets can be matched using a script name. For +example: +<pre> + \p{Greek} + \P{Han} +</pre> +Those that are not part of an identified script are lumped together as +"Common". The current list of scripts is: +</P> +<P> +Arabic, +Armenian, +Avestan, +Balinese, +Bamum, +Batak, +Bengali, +Bopomofo, +Brahmi, +Braille, +Buginese, +Buhid, +Canadian_Aboriginal, +Carian, +Chakma, +Cham, +Cherokee, +Common, +Coptic, +Cuneiform, +Cypriot, +Cyrillic, +Deseret, +Devanagari, +Egyptian_Hieroglyphs, +Ethiopic, +Georgian, +Glagolitic, +Gothic, +Greek, +Gujarati, +Gurmukhi, +Han, +Hangul, +Hanunoo, +Hebrew, +Hiragana, +Imperial_Aramaic, +Inherited, +Inscriptional_Pahlavi, +Inscriptional_Parthian, +Javanese, +Kaithi, +Kannada, +Katakana, +Kayah_Li, +Kharoshthi, +Khmer, +Lao, +Latin, +Lepcha, +Limbu, +Linear_B, +Lisu, +Lycian, +Lydian, +Malayalam, +Mandaic, +Meetei_Mayek, +Meroitic_Cursive, +Meroitic_Hieroglyphs, +Miao, +Mongolian, +Myanmar, +New_Tai_Lue, +Nko, +Ogham, +Old_Italic, +Old_Persian, +Old_South_Arabian, +Old_Turkic, +Ol_Chiki, +Oriya, +Osmanya, +Phags_Pa, +Phoenician, +Rejang, +Runic, +Samaritan, +Saurashtra, +Sharada, +Shavian, +Sinhala, +Sora_Sompeng, +Sundanese, +Syloti_Nagri, +Syriac, +Tagalog, +Tagbanwa, +Tai_Le, +Tai_Tham, +Tai_Viet, +Takri, +Tamil, +Telugu, +Thaana, +Thai, +Tibetan, +Tifinagh, +Ugaritic, +Vai, +Yi. +</P> +<P> +Each character has exactly one Unicode general category property, specified by +a two-letter abbreviation. For compatibility with Perl, negation can be +specified by including a circumflex between the opening brace and the property +name. For example, \p{^Lu} is the same as \P{Lu}. +</P> +<P> +If only one letter is specified with \p or \P, it includes all the general +category properties that start with that letter. In this case, in the absence +of negation, the curly brackets in the escape sequence are optional; these two +examples have the same effect: +<pre> + \p{L} + \pL +</pre> +The following general category property codes are supported: +<pre> + C Other + Cc Control + Cf Format + Cn Unassigned + Co Private use + Cs Surrogate + + L Letter + Ll Lower case letter + Lm Modifier letter + Lo Other letter + Lt Title case letter + Lu Upper case letter + + M Mark + Mc Spacing mark + Me Enclosing mark + Mn Non-spacing mark + + N Number + Nd Decimal number + Nl Letter number + No Other number + + P Punctuation + Pc Connector punctuation + Pd Dash punctuation + Pe Close punctuation + Pf Final punctuation + Pi Initial punctuation + Po Other punctuation + Ps Open punctuation + + S Symbol + Sc Currency symbol + Sk Modifier symbol + Sm Mathematical symbol + So Other symbol + + Z Separator + Zl Line separator + Zp Paragraph separator + Zs Space separator +</pre> +The special property L& is also supported: it matches a character that has +the Lu, Ll, or Lt property, in other words, a letter that is not classified as +a modifier or "other". +</P> +<P> +The Cs (Surrogate) property applies only to characters in the range U+D800 to +U+DFFF. Such characters are not valid in Unicode strings and so +cannot be tested by PCRE, unless UTF validity checking has been turned off +(see the discussion of PCRE_NO_UTF8_CHECK, PCRE_NO_UTF16_CHECK and +PCRE_NO_UTF32_CHECK in the +<a href="pcreapi.html"><b>pcreapi</b></a> +page). Perl does not support the Cs property. +</P> +<P> +The long synonyms for property names that Perl supports (such as \p{Letter}) +are not supported by PCRE, nor is it permitted to prefix any of these +properties with "Is". +</P> +<P> +No character that is in the Unicode table has the Cn (unassigned) property. +Instead, this property is assumed for any code point that is not in the +Unicode table. +</P> +<P> +Specifying caseless matching does not affect these escape sequences. For +example, \p{Lu} always matches only upper case letters. This is different from +the behaviour of current versions of Perl. +</P> +<P> +Matching characters by Unicode property is not fast, because PCRE has to do a +multistage table lookup in order to find a character's property. That is why +the traditional escape sequences such as \d and \w do not use Unicode +properties in PCRE by default, though you can make them do so by setting the +PCRE_UCP option or by starting the pattern with (*UCP). +</P> +<br><b> +Extended grapheme clusters +</b><br> +<P> +The \X escape matches any number of Unicode characters that form an "extended +grapheme cluster", and treats the sequence as an atomic group +<a href="#atomicgroup">(see below).</a> +Up to and including release 8.31, PCRE matched an earlier, simpler definition +that was equivalent to +<pre> + (?>\PM\pM*) +</pre> +That is, it matched a character without the "mark" property, followed by zero +or more characters with the "mark" property. Characters with the "mark" +property are typically non-spacing accents that affect the preceding character. +</P> +<P> +This simple definition was extended in Unicode to include more complicated +kinds of composite character by giving each character a grapheme breaking +property, and creating rules that use these properties to define the boundaries +of extended grapheme clusters. In releases of PCRE later than 8.31, \X matches +one of these clusters. +</P> +<P> +\X always matches at least one character. Then it decides whether to add +additional characters according to the following rules for ending a cluster: +</P> +<P> +1. End at the end of the subject string. +</P> +<P> +2. Do not end between CR and LF; otherwise end after any control character. +</P> +<P> +3. Do not break Hangul (a Korean script) syllable sequences. Hangul characters +are of five types: L, V, T, LV, and LVT. An L character may be followed by an +L, V, LV, or LVT character; an LV or V character may be followed by a V or T +character; an LVT or T character may be follwed only by a T character. +</P> +<P> +4. Do not end before extending characters or spacing marks. Characters with +the "mark" property always have the "extend" grapheme breaking property. +</P> +<P> +5. Do not end after prepend characters. +</P> +<P> +6. Otherwise, end the cluster. +<a name="extraprops"></a></P> +<br><b> +PCRE's additional properties +</b><br> +<P> +As well as the standard Unicode properties described above, PCRE supports four +more that make it possible to convert traditional escape sequences such as \w +and \s to use Unicode properties. PCRE uses these non-standard, non-Perl +properties internally when PCRE_UCP is set. However, they may also be used +explicitly. These properties are: +<pre> + Xan Any alphanumeric character + Xps Any POSIX space character + Xsp Any Perl space character + Xwd Any Perl "word" character +</pre> +Xan matches characters that have either the L (letter) or the N (number) +property. Xps matches the characters tab, linefeed, vertical tab, form feed, or +carriage return, and any other character that has the Z (separator) property. +Xsp is the same as Xps; it used to exclude vertical tab, for Perl +compatibility, but Perl changed, and so PCRE followed at release 8.34. Xwd +matches the same characters as Xan, plus underscore. +</P> +<P> +There is another non-standard property, Xuc, which matches any character that +can be represented by a Universal Character Name in C++ and other programming +languages. These are the characters $, @, ` (grave accent), and all characters +with Unicode code points greater than or equal to U+00A0, except for the +surrogates U+D800 to U+DFFF. Note that most base (ASCII) characters are +excluded. (Universal Character Names are of the form \uHHHH or \UHHHHHHHH +where H is a hexadecimal digit. Note that the Xuc property does not match these +sequences but the characters that they represent.) +<a name="resetmatchstart"></a></P> +<br><b> +Resetting the match start +</b><br> +<P> +The escape sequence \K causes any previously matched characters not to be +included in the final matched sequence. For example, the pattern: +<pre> + foo\Kbar +</pre> +matches "foobar", but reports that it has matched "bar". This feature is +similar to a lookbehind assertion +<a href="#lookbehind">(described below).</a> +However, in this case, the part of the subject before the real match does not +have to be of fixed length, as lookbehind assertions do. The use of \K does +not interfere with the setting of +<a href="#subpattern">captured substrings.</a> +For example, when the pattern +<pre> + (foo)\Kbar +</pre> +matches "foobar", the first substring is still set to "foo". +</P> +<P> +Perl documents that the use of \K within assertions is "not well defined". In +PCRE, \K is acted upon when it occurs inside positive assertions, but is +ignored in negative assertions. Note that when a pattern such as (?=ab\K) +matches, the reported start of the match can be greater than the end of the +match. +<a name="smallassertions"></a></P> +<br><b> +Simple assertions +</b><br> +<P> +The final use of backslash is for certain simple assertions. An assertion +specifies a condition that has to be met at a particular point in a match, +without consuming any characters from the subject string. The use of +subpatterns for more complicated assertions is described +<a href="#bigassertions">below.</a> +The backslashed assertions are: +<pre> + \b matches at a word boundary + \B matches when not at a word boundary + \A matches at the start of the subject + \Z matches at the end of the subject + also matches before a newline at the end of the subject + \z matches only at the end of the subject + \G matches at the first matching position in the subject +</pre> +Inside a character class, \b has a different meaning; it matches the backspace +character. If any other of these assertions appears in a character class, by +default it matches the corresponding literal character (for example, \B +matches the letter B). However, if the PCRE_EXTRA option is set, an "invalid +escape sequence" error is generated instead. +</P> +<P> +A word boundary is a position in the subject string where the current character +and the previous character do not both match \w or \W (i.e. one matches +\w and the other matches \W), or the start or end of the string if the +first or last character matches \w, respectively. In a UTF mode, the meanings +of \w and \W can be changed by setting the PCRE_UCP option. When this is +done, it also affects \b and \B. Neither PCRE nor Perl has a separate "start +of word" or "end of word" metasequence. However, whatever follows \b normally +determines which it is. For example, the fragment \ba matches "a" at the start +of a word. +</P> +<P> +The \A, \Z, and \z assertions differ from the traditional circumflex and +dollar (described in the next section) in that they only ever match at the very +start and end of the subject string, whatever options are set. Thus, they are +independent of multiline mode. These three assertions are not affected by the +PCRE_NOTBOL or PCRE_NOTEOL options, which affect only the behaviour of the +circumflex and dollar metacharacters. However, if the <i>startoffset</i> +argument of <b>pcre_exec()</b> is non-zero, indicating that matching is to start +at a point other than the beginning of the subject, \A can never match. The +difference between \Z and \z is that \Z matches before a newline at the end +of the string as well as at the very end, whereas \z matches only at the end. +</P> +<P> +The \G assertion is true only when the current matching position is at the +start point of the match, as specified by the <i>startoffset</i> argument of +<b>pcre_exec()</b>. It differs from \A when the value of <i>startoffset</i> is +non-zero. By calling <b>pcre_exec()</b> multiple times with appropriate +arguments, you can mimic Perl's /g option, and it is in this kind of +implementation where \G can be useful. +</P> +<P> +Note, however, that PCRE's interpretation of \G, as the start of the current +match, is subtly different from Perl's, which defines it as the end of the +previous match. In Perl, these can be different when the previously matched +string was empty. Because PCRE does just one match at a time, it cannot +reproduce this behaviour. +</P> +<P> +If all the alternatives of a pattern begin with \G, the expression is anchored +to the starting match position, and the "anchored" flag is set in the compiled +regular expression. +</P> +<br><a name="SEC6" href="#TOC1">CIRCUMFLEX AND DOLLAR</a><br> +<P> +The circumflex and dollar metacharacters are zero-width assertions. That is, +they test for a particular condition being true without consuming any +characters from the subject string. +</P> +<P> +Outside a character class, in the default matching mode, the circumflex +character is an assertion that is true only if the current matching point is at +the start of the subject string. If the <i>startoffset</i> argument of +<b>pcre_exec()</b> is non-zero, circumflex can never match if the PCRE_MULTILINE +option is unset. Inside a character class, circumflex has an entirely different +meaning +<a href="#characterclass">(see below).</a> +</P> +<P> +Circumflex need not be the first character of the pattern if a number of +alternatives are involved, but it should be the first thing in each alternative +in which it appears if the pattern is ever to match that branch. If all +possible alternatives start with a circumflex, that is, if the pattern is +constrained to match only at the start of the subject, it is said to be an +"anchored" pattern. (There are also other constructs that can cause a pattern +to be anchored.) +</P> +<P> +The dollar character is an assertion that is true only if the current matching +point is at the end of the subject string, or immediately before a newline at +the end of the string (by default). Note, however, that it does not actually +match the newline. Dollar need not be the last character of the pattern if a +number of alternatives are involved, but it should be the last item in any +branch in which it appears. Dollar has no special meaning in a character class. +</P> +<P> +The meaning of dollar can be changed so that it matches only at the very end of +the string, by setting the PCRE_DOLLAR_ENDONLY option at compile time. This +does not affect the \Z assertion. +</P> +<P> +The meanings of the circumflex and dollar characters are changed if the +PCRE_MULTILINE option is set. When this is the case, a circumflex matches +immediately after internal newlines as well as at the start of the subject +string. It does not match after a newline that ends the string. A dollar +matches before any newlines in the string, as well as at the very end, when +PCRE_MULTILINE is set. When newline is specified as the two-character +sequence CRLF, isolated CR and LF characters do not indicate newlines. +</P> +<P> +For example, the pattern /^abc$/ matches the subject string "def\nabc" (where +\n represents a newline) in multiline mode, but not otherwise. Consequently, +patterns that are anchored in single line mode because all branches start with +^ are not anchored in multiline mode, and a match for circumflex is possible +when the <i>startoffset</i> argument of <b>pcre_exec()</b> is non-zero. The +PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set. +</P> +<P> +Note that the sequences \A, \Z, and \z can be used to match the start and +end of the subject in both modes, and if all branches of a pattern start with +\A it is always anchored, whether or not PCRE_MULTILINE is set. +<a name="fullstopdot"></a></P> +<br><a name="SEC7" href="#TOC1">FULL STOP (PERIOD, DOT) AND \N</a><br> +<P> +Outside a character class, a dot in the pattern matches any one character in +the subject string except (by default) a character that signifies the end of a +line. +</P> +<P> +When a line ending is defined as a single character, dot never matches that +character; when the two-character sequence CRLF is used, dot does not match CR +if it is immediately followed by LF, but otherwise it matches all characters +(including isolated CRs and LFs). When any Unicode line endings are being +recognized, dot does not match CR or LF or any of the other line ending +characters. +</P> +<P> +The behaviour of dot with regard to newlines can be changed. If the PCRE_DOTALL +option is set, a dot matches any one character, without exception. If the +two-character sequence CRLF is present in the subject string, it takes two dots +to match it. +</P> +<P> +The handling of dot is entirely independent of the handling of circumflex and +dollar, the only relationship being that they both involve newlines. Dot has no +special meaning in a character class. +</P> +<P> +The escape sequence \N behaves like a dot, except that it is not affected by +the PCRE_DOTALL option. In other words, it matches any character except one +that signifies the end of a line. Perl also uses \N to match characters by +name; PCRE does not support this. +</P> +<br><a name="SEC8" href="#TOC1">MATCHING A SINGLE DATA UNIT</a><br> +<P> +Outside a character class, the escape sequence \C matches any one data unit, +whether or not a UTF mode is set. In the 8-bit library, one data unit is one +byte; in the 16-bit library it is a 16-bit unit; in the 32-bit library it is +a 32-bit unit. Unlike a dot, \C always +matches line-ending characters. The feature is provided in Perl in order to +match individual bytes in UTF-8 mode, but it is unclear how it can usefully be +used. Because \C breaks up characters into individual data units, matching one +unit with \C in a UTF mode means that the rest of the string may start with a +malformed UTF character. This has undefined results, because PCRE assumes that +it is dealing with valid UTF strings (and by default it checks this at the +start of processing unless the PCRE_NO_UTF8_CHECK, PCRE_NO_UTF16_CHECK or +PCRE_NO_UTF32_CHECK option is used). +</P> +<P> +PCRE does not allow \C to appear in lookbehind assertions +<a href="#lookbehind">(described below)</a> +in a UTF mode, because this would make it impossible to calculate the length of +the lookbehind. +</P> +<P> +In general, the \C escape sequence is best avoided. However, one +way of using it that avoids the problem of malformed UTF characters is to use a +lookahead to check the length of the next character, as in this pattern, which +could be used with a UTF-8 string (ignore white space and line breaks): +<pre> + (?| (?=[\x00-\x7f])(\C) | + (?=[\x80-\x{7ff}])(\C)(\C) | + (?=[\x{800}-\x{ffff}])(\C)(\C)(\C) | + (?=[\x{10000}-\x{1fffff}])(\C)(\C)(\C)(\C)) +</pre> +A group that starts with (?| resets the capturing parentheses numbers in each +alternative (see +<a href="#dupsubpatternnumber">"Duplicate Subpattern Numbers"</a> +below). The assertions at the start of each branch check the next UTF-8 +character for values whose encoding uses 1, 2, 3, or 4 bytes, respectively. The +character's individual bytes are then captured by the appropriate number of +groups. +<a name="characterclass"></a></P> +<br><a name="SEC9" href="#TOC1">SQUARE BRACKETS AND CHARACTER CLASSES</a><br> +<P> +An opening square bracket introduces a character class, terminated by a closing +square bracket. A closing square bracket on its own is not special by default. +However, if the PCRE_JAVASCRIPT_COMPAT option is set, a lone closing square +bracket causes a compile-time error. If a closing square bracket is required as +a member of the class, it should be the first data character in the class +(after an initial circumflex, if present) or escaped with a backslash. +</P> +<P> +A character class matches a single character in the subject. In a UTF mode, the +character may be more than one data unit long. A matched character must be in +the set of characters defined by the class, unless the first character in the +class definition is a circumflex, in which case the subject character must not +be in the set defined by the class. If a circumflex is actually required as a +member of the class, ensure it is not the first character, or escape it with a +backslash. +</P> +<P> +For example, the character class [aeiou] matches any lower case vowel, while +[^aeiou] matches any character that is not a lower case vowel. Note that a +circumflex is just a convenient notation for specifying the characters that +are in the class by enumerating those that are not. A class that starts with a +circumflex is not an assertion; it still consumes a character from the subject +string, and therefore it fails if the current pointer is at the end of the +string. +</P> +<P> +In UTF-8 (UTF-16, UTF-32) mode, characters with values greater than 255 (0xffff) +can be included in a class as a literal string of data units, or by using the +\x{ escaping mechanism. +</P> +<P> +When caseless matching is set, any letters in a class represent both their +upper case and lower case versions, so for example, a caseless [aeiou] matches +"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a +caseful version would. In a UTF mode, PCRE always understands the concept of +case for characters whose values are less than 128, so caseless matching is +always possible. For characters with higher values, the concept of case is +supported if PCRE is compiled with Unicode property support, but not otherwise. +If you want to use caseless matching in a UTF mode for characters 128 and +above, you must ensure that PCRE is compiled with Unicode property support as +well as with UTF support. +</P> +<P> +Characters that might indicate line breaks are never treated in any special way +when matching character classes, whatever line-ending sequence is in use, and +whatever setting of the PCRE_DOTALL and PCRE_MULTILINE options is used. A class +such as [^a] always matches one of these characters. +</P> +<P> +The minus (hyphen) character can be used to specify a range of characters in a +character class. For example, [d-m] matches any letter between d and m, +inclusive. If a minus character is required in a class, it must be escaped with +a backslash or appear in a position where it cannot be interpreted as +indicating a range, typically as the first or last character in the class, or +immediately after a range. For example, [b-d-z] matches letters in the range b +to d, a hyphen character, or z. +</P> +<P> +It is not possible to have the literal character "]" as the end character of a +range. A pattern such as [W-]46] is interpreted as a class of two characters +("W" and "-") followed by a literal string "46]", so it would match "W46]" or +"-46]". However, if the "]" is escaped with a backslash it is interpreted as +the end of range, so [W-\]46] is interpreted as a class containing a range +followed by two other characters. The octal or hexadecimal representation of +"]" can also be used to end a range. +</P> +<P> +An error is generated if a POSIX character class (see below) or an escape +sequence other than one that defines a single character appears at a point +where a range ending character is expected. For example, [z-\xff] is valid, +but [A-\d] and [A-[:digit:]] are not. +</P> +<P> +Ranges operate in the collating sequence of character values. They can also be +used for characters specified numerically, for example [\000-\037]. Ranges +can include any characters that are valid for the current mode. +</P> +<P> +If a range that includes letters is used when caseless matching is set, it +matches the letters in either case. For example, [W-c] is equivalent to +[][\\^_`wxyzabc], matched caselessly, and in a non-UTF mode, if character +tables for a French locale are in use, [\xc8-\xcb] matches accented E +characters in both cases. In UTF modes, PCRE supports the concept of case for +characters with values greater than 128 only when it is compiled with Unicode +property support. +</P> +<P> +The character escape sequences \d, \D, \h, \H, \p, \P, \s, \S, \v, +\V, \w, and \W may appear in a character class, and add the characters that +they match to the class. For example, [\dABCDEF] matches any hexadecimal +digit. In UTF modes, the PCRE_UCP option affects the meanings of \d, \s, \w +and their upper case partners, just as it does when they appear outside a +character class, as described in the section entitled +<a href="#genericchartypes">"Generic character types"</a> +above. The escape sequence \b has a different meaning inside a character +class; it matches the backspace character. The sequences \B, \N, \R, and \X +are not special inside a character class. Like any other unrecognized escape +sequences, they are treated as the literal characters "B", "N", "R", and "X" by +default, but cause an error if the PCRE_EXTRA option is set. +</P> +<P> +A circumflex can conveniently be used with the upper case character types to +specify a more restricted set of characters than the matching lower case type. +For example, the class [^\W_] matches any letter or digit, but not underscore, +whereas [\w] includes underscore. A positive character class should be read as +"something OR something OR ..." and a negative class as "NOT something AND NOT +something AND NOT ...". +</P> +<P> +The only metacharacters that are recognized in character classes are backslash, +hyphen (only where it can be interpreted as specifying a range), circumflex +(only at the start), opening square bracket (only when it can be interpreted as +introducing a POSIX class name, or for a special compatibility feature - see +the next two sections), and the terminating closing square bracket. However, +escaping other non-alphanumeric characters does no harm. +</P> +<br><a name="SEC10" href="#TOC1">POSIX CHARACTER CLASSES</a><br> +<P> +Perl supports the POSIX notation for character classes. This uses names +enclosed by [: and :] within the enclosing square brackets. PCRE also supports +this notation. For example, +<pre> + [01[:alpha:]%] +</pre> +matches "0", "1", any alphabetic character, or "%". The supported class names +are: +<pre> + alnum letters and digits + alpha letters + ascii character codes 0 - 127 + blank space or tab only + cntrl control characters + digit decimal digits (same as \d) + graph printing characters, excluding space + lower lower case letters + print printing characters, including space + punct printing characters, excluding letters and digits and space + space white space (the same as \s from PCRE 8.34) + upper upper case letters + word "word" characters (same as \w) + xdigit hexadecimal digits +</pre> +The default "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13), +and space (32). If locale-specific matching is taking place, the list of space +characters may be different; there may be fewer or more of them. "Space" used +to be different to \s, which did not include VT, for Perl compatibility. +However, Perl changed at release 5.18, and PCRE followed at release 8.34. +"Space" and \s now match the same set of characters. +</P> +<P> +The name "word" is a Perl extension, and "blank" is a GNU extension from Perl +5.8. Another Perl extension is negation, which is indicated by a ^ character +after the colon. For example, +<pre> + [12[:^digit:]] +</pre> +matches "1", "2", or any non-digit. PCRE (and Perl) also recognize the POSIX +syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not +supported, and an error is given if they are encountered. +</P> +<P> +By default, characters with values greater than 128 do not match any of the +POSIX character classes. However, if the PCRE_UCP option is passed to +<b>pcre_compile()</b>, some of the classes are changed so that Unicode character +properties are used. This is achieved by replacing certain POSIX classes by +other sequences, as follows: +<pre> + [:alnum:] becomes \p{Xan} + [:alpha:] becomes \p{L} + [:blank:] becomes \h + [:digit:] becomes \p{Nd} + [:lower:] becomes \p{Ll} + [:space:] becomes \p{Xps} + [:upper:] becomes \p{Lu} + [:word:] becomes \p{Xwd} +</pre> +Negated versions, such as [:^alpha:] use \P instead of \p. Three other POSIX +classes are handled specially in UCP mode: +</P> +<P> +[:graph:] +This matches characters that have glyphs that mark the page when printed. In +Unicode property terms, it matches all characters with the L, M, N, P, S, or Cf +properties, except for: +<pre> + U+061C Arabic Letter Mark + U+180E Mongolian Vowel Separator + U+2066 - U+2069 Various "isolate"s + +</PRE> +</P> +<P> +[:print:] +This matches the same characters as [:graph:] plus space characters that are +not controls, that is, characters with the Zs property. +</P> +<P> +[:punct:] +This matches all characters that have the Unicode P (punctuation) property, +plus those characters whose code points are less than 128 that have the S +(Symbol) property. +</P> +<P> +The other POSIX classes are unchanged, and match only characters with code +points less than 128. +</P> +<br><a name="SEC11" href="#TOC1">COMPATIBILITY FEATURE FOR WORD BOUNDARIES</a><br> +<P> +In the POSIX.2 compliant library that was included in 4.4BSD Unix, the ugly +syntax [[:<:]] and [[:>:]] is used for matching "start of word" and "end of +word". PCRE treats these items as follows: +<pre> + [[:<:]] is converted to \b(?=\w) + [[:>:]] is converted to \b(?<=\w) +</pre> +Only these exact character sequences are recognized. A sequence such as +[a[:<:]b] provokes error for an unrecognized POSIX class name. This support is +not compatible with Perl. It is provided to help migrations from other +environments, and is best not used in any new patterns. Note that \b matches +at the start and the end of a word (see +<a href="#smallassertions">"Simple assertions"</a> +above), and in a Perl-style pattern the preceding or following character +normally shows which is wanted, without the need for the assertions that are +used above in order to give exactly the POSIX behaviour. +</P> +<br><a name="SEC12" href="#TOC1">VERTICAL BAR</a><br> +<P> +Vertical bar characters are used to separate alternative patterns. For example, +the pattern +<pre> + gilbert|sullivan +</pre> +matches either "gilbert" or "sullivan". Any number of alternatives may appear, +and an empty alternative is permitted (matching the empty string). The matching +process tries each alternative in turn, from left to right, and the first one +that succeeds is used. If the alternatives are within a subpattern +<a href="#subpattern">(defined below),</a> +"succeeds" means matching the rest of the main pattern as well as the +alternative in the subpattern. +</P> +<br><a name="SEC13" href="#TOC1">INTERNAL OPTION SETTING</a><br> +<P> +The settings of the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and +PCRE_EXTENDED options (which are Perl-compatible) can be changed from within +the pattern by a sequence of Perl option letters enclosed between "(?" and ")". +The option letters are +<pre> + i for PCRE_CASELESS + m for PCRE_MULTILINE + s for PCRE_DOTALL + x for PCRE_EXTENDED +</pre> +For example, (?im) sets caseless, multiline matching. It is also possible to +unset these options by preceding the letter with a hyphen, and a combined +setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and +PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also +permitted. If a letter appears both before and after the hyphen, the option is +unset. +</P> +<P> +The PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and PCRE_EXTRA can be +changed in the same way as the Perl-compatible options by using the characters +J, U and X respectively. +</P> +<P> +When one of these option changes occurs at top level (that is, not inside +subpattern parentheses), the change applies to the remainder of the pattern +that follows. If the change is placed right at the start of a pattern, PCRE +extracts it into the global options (and it will therefore show up in data +extracted by the <b>pcre_fullinfo()</b> function). +</P> +<P> +An option change within a subpattern (see below for a description of +subpatterns) affects only that part of the subpattern that follows it, so +<pre> + (a(?i)b)c +</pre> +matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). +By this means, options can be made to have different settings in different +parts of the pattern. Any changes made in one alternative do carry on +into subsequent branches within the same subpattern. For example, +<pre> + (a(?i)b|c) +</pre> +matches "ab", "aB", "c", and "C", even though when matching "C" the first +branch is abandoned before the option setting. This is because the effects of +option settings happen at compile time. There would be some very weird +behaviour otherwise. +</P> +<P> +<b>Note:</b> There are other PCRE-specific options that can be set by the +application when the compiling or matching functions are called. In some cases +the pattern can contain special leading sequences such as (*CRLF) to override +what the application has set or what has been defaulted. Details are given in +the section entitled +<a href="#newlineseq">"Newline sequences"</a> +above. There are also the (*UTF8), (*UTF16),(*UTF32), and (*UCP) leading +sequences that can be used to set UTF and Unicode property modes; they are +equivalent to setting the PCRE_UTF8, PCRE_UTF16, PCRE_UTF32 and the PCRE_UCP +options, respectively. The (*UTF) sequence is a generic version that can be +used with any of the libraries. However, the application can set the +PCRE_NEVER_UTF option, which locks out the use of the (*UTF) sequences. +<a name="subpattern"></a></P> +<br><a name="SEC14" href="#TOC1">SUBPATTERNS</a><br> +<P> +Subpatterns are delimited by parentheses (round brackets), which can be nested. +Turning part of a pattern into a subpattern does two things: +<br> +<br> +1. It localizes a set of alternatives. For example, the pattern +<pre> + cat(aract|erpillar|) +</pre> +matches "cataract", "caterpillar", or "cat". Without the parentheses, it would +match "cataract", "erpillar" or an empty string. +<br> +<br> +2. It sets up the subpattern as a capturing subpattern. This means that, when +the whole pattern matches, that portion of the subject string that matched the +subpattern is passed back to the caller via the <i>ovector</i> argument of the +matching function. (This applies only to the traditional matching functions; +the DFA matching functions do not support capturing.) +</P> +<P> +Opening parentheses are counted from left to right (starting from 1) to obtain +numbers for the capturing subpatterns. For example, if the string "the red +king" is matched against the pattern +<pre> + the ((red|white) (king|queen)) +</pre> +the captured substrings are "red king", "red", and "king", and are numbered 1, +2, and 3, respectively. +</P> +<P> +The fact that plain parentheses fulfil two functions is not always helpful. +There are often times when a grouping subpattern is required without a +capturing requirement. If an opening parenthesis is followed by a question mark +and a colon, the subpattern does not do any capturing, and is not counted when +computing the number of any subsequent capturing subpatterns. For example, if +the string "the white queen" is matched against the pattern +<pre> + the ((?:red|white) (king|queen)) +</pre> +the captured substrings are "white queen" and "queen", and are numbered 1 and +2. The maximum number of capturing subpatterns is 65535. +</P> +<P> +As a convenient shorthand, if any option settings are required at the start of +a non-capturing subpattern, the option letters may appear between the "?" and +the ":". Thus the two patterns +<pre> + (?i:saturday|sunday) + (?:(?i)saturday|sunday) +</pre> +match exactly the same set of strings. Because alternative branches are tried +from left to right, and options are not reset until the end of the subpattern +is reached, an option setting in one branch does affect subsequent branches, so +the above patterns match "SUNDAY" as well as "Saturday". +<a name="dupsubpatternnumber"></a></P> +<br><a name="SEC15" href="#TOC1">DUPLICATE SUBPATTERN NUMBERS</a><br> +<P> +Perl 5.10 introduced a feature whereby each alternative in a subpattern uses +the same numbers for its capturing parentheses. Such a subpattern starts with +(?| and is itself a non-capturing subpattern. For example, consider this +pattern: +<pre> + (?|(Sat)ur|(Sun))day +</pre> +Because the two alternatives are inside a (?| group, both sets of capturing +parentheses are numbered one. Thus, when the pattern matches, you can look +at captured substring number one, whichever alternative matched. This construct +is useful when you want to capture part, but not all, of one of a number of +alternatives. Inside a (?| group, parentheses are numbered as usual, but the +number is reset at the start of each branch. The numbers of any capturing +parentheses that follow the subpattern start after the highest number used in +any branch. The following example is taken from the Perl documentation. The +numbers underneath show in which buffer the captured content will be stored. +<pre> + # before ---------------branch-reset----------- after + / ( a ) (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x + # 1 2 2 3 2 3 4 +</pre> +A back reference to a numbered subpattern uses the most recent value that is +set for that number by any subpattern. The following pattern matches "abcabc" +or "defdef": +<pre> + /(?|(abc)|(def))\1/ +</pre> +In contrast, a subroutine call to a numbered subpattern always refers to the +first one in the pattern with the given number. The following pattern matches +"abcabc" or "defabc": +<pre> + /(?|(abc)|(def))(?1)/ +</pre> +If a +<a href="#conditions">condition test</a> +for a subpattern's having matched refers to a non-unique number, the test is +true if any of the subpatterns of that number have matched. +</P> +<P> +An alternative approach to using this "branch reset" feature is to use +duplicate named subpatterns, as described in the next section. +</P> +<br><a name="SEC16" href="#TOC1">NAMED SUBPATTERNS</a><br> +<P> +Identifying capturing parentheses by number is simple, but it can be very hard +to keep track of the numbers in complicated regular expressions. Furthermore, +if an expression is modified, the numbers may change. To help with this +difficulty, PCRE supports the naming of subpatterns. This feature was not +added to Perl until release 5.10. Python had the feature earlier, and PCRE +introduced it at release 4.0, using the Python syntax. PCRE now supports both +the Perl and the Python syntax. Perl allows identically numbered subpatterns to +have different names, but PCRE does not. +</P> +<P> +In PCRE, a subpattern can be named in one of three ways: (?<name>...) or +(?'name'...) as in Perl, or (?P<name>...) as in Python. References to capturing +parentheses from other parts of the pattern, such as +<a href="#backreferences">back references,</a> +<a href="#recursion">recursion,</a> +and +<a href="#conditions">conditions,</a> +can be made by name as well as by number. +</P> +<P> +Names consist of up to 32 alphanumeric characters and underscores, but must +start with a non-digit. Named capturing parentheses are still allocated numbers +as well as names, exactly as if the names were not present. The PCRE API +provides function calls for extracting the name-to-number translation table +from a compiled pattern. There is also a convenience function for extracting a +captured substring by name. +</P> +<P> +By default, a name must be unique within a pattern, but it is possible to relax +this constraint by setting the PCRE_DUPNAMES option at compile time. (Duplicate +names are also always permitted for subpatterns with the same number, set up as +described in the previous section.) Duplicate names can be useful for patterns +where only one instance of the named parentheses can match. Suppose you want to +match the name of a weekday, either as a 3-letter abbreviation or as the full +name, and in both cases you want to extract the abbreviation. This pattern +(ignoring the line breaks) does the job: +<pre> + (?<DN>Mon|Fri|Sun)(?:day)?| + (?<DN>Tue)(?:sday)?| + (?<DN>Wed)(?:nesday)?| + (?<DN>Thu)(?:rsday)?| + (?<DN>Sat)(?:urday)? +</pre> +There are five capturing substrings, but only one is ever set after a match. +(An alternative way of solving this problem is to use a "branch reset" +subpattern, as described in the previous section.) +</P> +<P> +The convenience function for extracting the data by name returns the substring +for the first (and in this example, the only) subpattern of that name that +matched. This saves searching to find which numbered subpattern it was. +</P> +<P> +If you make a back reference to a non-unique named subpattern from elsewhere in +the pattern, the subpatterns to which the name refers are checked in the order +in which they appear in the overall pattern. The first one that is set is used +for the reference. For example, this pattern matches both "foofoo" and +"barbar" but not "foobar" or "barfoo": +<pre> + (?:(?<n>foo)|(?<n>bar))\k<n> + +</PRE> +</P> +<P> +If you make a subroutine call to a non-unique named subpattern, the one that +corresponds to the first occurrence of the name is used. In the absence of +duplicate numbers (see the previous section) this is the one with the lowest +number. +</P> +<P> +If you use a named reference in a condition +test (see the +<a href="#conditions">section about conditions</a> +below), either to check whether a subpattern has matched, or to check for +recursion, all subpatterns with the same name are tested. If the condition is +true for any one of them, the overall condition is true. This is the same +behaviour as testing by number. For further details of the interfaces for +handling named subpatterns, see the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<P> +<b>Warning:</b> You cannot use different names to distinguish between two +subpatterns with the same number because PCRE uses only the numbers when +matching. For this reason, an error is given at compile time if different names +are given to subpatterns with the same number. However, you can always give the +same name to subpatterns with the same number, even when PCRE_DUPNAMES is not +set. +</P> +<br><a name="SEC17" href="#TOC1">REPETITION</a><br> +<P> +Repetition is specified by quantifiers, which can follow any of the following +items: +<pre> + a literal data character + the dot metacharacter + the \C escape sequence + the \X escape sequence + the \R escape sequence + an escape such as \d or \pL that matches a single character + a character class + a back reference (see next section) + a parenthesized subpattern (including assertions) + a subroutine call to a subpattern (recursive or otherwise) +</pre> +The general repetition quantifier specifies a minimum and maximum number of +permitted matches, by giving the two numbers in curly brackets (braces), +separated by a comma. The numbers must be less than 65536, and the first must +be less than or equal to the second. For example: +<pre> + z{2,4} +</pre> +matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special +character. If the second number is omitted, but the comma is present, there is +no upper limit; if the second number and the comma are both omitted, the +quantifier specifies an exact number of required matches. Thus +<pre> + [aeiou]{3,} +</pre> +matches at least 3 successive vowels, but may match many more, while +<pre> + \d{8} +</pre> +matches exactly 8 digits. An opening curly bracket that appears in a position +where a quantifier is not allowed, or one that does not match the syntax of a +quantifier, is taken as a literal character. For example, {,6} is not a +quantifier, but a literal string of four characters. +</P> +<P> +In UTF modes, quantifiers apply to characters rather than to individual data +units. Thus, for example, \x{100}{2} matches two characters, each of +which is represented by a two-byte sequence in a UTF-8 string. Similarly, +\X{3} matches three Unicode extended grapheme clusters, each of which may be +several data units long (and they may be of different lengths). +</P> +<P> +The quantifier {0} is permitted, causing the expression to behave as if the +previous item and the quantifier were not present. This may be useful for +subpatterns that are referenced as +<a href="#subpatternsassubroutines">subroutines</a> +from elsewhere in the pattern (but see also the section entitled +<a href="#subdefine">"Defining subpatterns for use by reference only"</a> +below). Items other than subpatterns that have a {0} quantifier are omitted +from the compiled pattern. +</P> +<P> +For convenience, the three most common quantifiers have single-character +abbreviations: +<pre> + * is equivalent to {0,} + + is equivalent to {1,} + ? is equivalent to {0,1} +</pre> +It is possible to construct infinite loops by following a subpattern that can +match no characters with a quantifier that has no upper limit, for example: +<pre> + (a?)* +</pre> +Earlier versions of Perl and PCRE used to give an error at compile time for +such patterns. However, because there are cases where this can be useful, such +patterns are now accepted, but if any repetition of the subpattern does in fact +match no characters, the loop is forcibly broken. +</P> +<P> +By default, the quantifiers are "greedy", that is, they match as much as +possible (up to the maximum number of permitted times), without causing the +rest of the pattern to fail. The classic example of where this gives problems +is in trying to match comments in C programs. These appear between /* and */ +and within the comment, individual * and / characters may appear. An attempt to +match C comments by applying the pattern +<pre> + /\*.*\*/ +</pre> +to the string +<pre> + /* first comment */ not comment /* second comment */ +</pre> +fails, because it matches the entire string owing to the greediness of the .* +item. +</P> +<P> +However, if a quantifier is followed by a question mark, it ceases to be +greedy, and instead matches the minimum number of times possible, so the +pattern +<pre> + /\*.*?\*/ +</pre> +does the right thing with the C comments. The meaning of the various +quantifiers is not otherwise changed, just the preferred number of matches. +Do not confuse this use of question mark with its use as a quantifier in its +own right. Because it has two uses, it can sometimes appear doubled, as in +<pre> + \d??\d +</pre> +which matches one digit by preference, but can match two if that is the only +way the rest of the pattern matches. +</P> +<P> +If the PCRE_UNGREEDY option is set (an option that is not available in Perl), +the quantifiers are not greedy by default, but individual ones can be made +greedy by following them with a question mark. In other words, it inverts the +default behaviour. +</P> +<P> +When a parenthesized subpattern is quantified with a minimum repeat count that +is greater than 1 or with a limited maximum, more memory is required for the +compiled pattern, in proportion to the size of the minimum or maximum. +</P> +<P> +If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent +to Perl's /s) is set, thus allowing the dot to match newlines, the pattern is +implicitly anchored, because whatever follows will be tried against every +character position in the subject string, so there is no point in retrying the +overall match at any position after the first. PCRE normally treats such a +pattern as though it were preceded by \A. +</P> +<P> +In cases where it is known that the subject string contains no newlines, it is +worth setting PCRE_DOTALL in order to obtain this optimization, or +alternatively using ^ to indicate anchoring explicitly. +</P> +<P> +However, there are some cases where the optimization cannot be used. When .* +is inside capturing parentheses that are the subject of a back reference +elsewhere in the pattern, a match at the start may fail where a later one +succeeds. Consider, for example: +<pre> + (.*)abc\1 +</pre> +If the subject is "xyz123abc123" the match point is the fourth character. For +this reason, such a pattern is not implicitly anchored. +</P> +<P> +Another case where implicit anchoring is not applied is when the leading .* is +inside an atomic group. Once again, a match at the start may fail where a later +one succeeds. Consider this pattern: +<pre> + (?>.*?a)b +</pre> +It matches "ab" in the subject "aab". The use of the backtracking control verbs +(*PRUNE) and (*SKIP) also disable this optimization. +</P> +<P> +When a capturing subpattern is repeated, the value captured is the substring +that matched the final iteration. For example, after +<pre> + (tweedle[dume]{3}\s*)+ +</pre> +has matched "tweedledum tweedledee" the value of the captured substring is +"tweedledee". However, if there are nested capturing subpatterns, the +corresponding captured values may have been set in previous iterations. For +example, after +<pre> + /(a|(b))+/ +</pre> +matches "aba" the value of the second captured substring is "b". +<a name="atomicgroup"></a></P> +<br><a name="SEC18" href="#TOC1">ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS</a><br> +<P> +With both maximizing ("greedy") and minimizing ("ungreedy" or "lazy") +repetition, failure of what follows normally causes the repeated item to be +re-evaluated to see if a different number of repeats allows the rest of the +pattern to match. Sometimes it is useful to prevent this, either to change the +nature of the match, or to cause it fail earlier than it otherwise might, when +the author of the pattern knows there is no point in carrying on. +</P> +<P> +Consider, for example, the pattern \d+foo when applied to the subject line +<pre> + 123456bar +</pre> +After matching all 6 digits and then failing to match "foo", the normal +action of the matcher is to try again with only 5 digits matching the \d+ +item, and then with 4, and so on, before ultimately failing. "Atomic grouping" +(a term taken from Jeffrey Friedl's book) provides the means for specifying +that once a subpattern has matched, it is not to be re-evaluated in this way. +</P> +<P> +If we use atomic grouping for the previous example, the matcher gives up +immediately on failing to match "foo" the first time. The notation is a kind of +special parenthesis, starting with (?> as in this example: +<pre> + (?>\d+)foo +</pre> +This kind of parenthesis "locks up" the part of the pattern it contains once +it has matched, and a failure further into the pattern is prevented from +backtracking into it. Backtracking past it to previous items, however, works as +normal. +</P> +<P> +An alternative description is that a subpattern of this type matches the string +of characters that an identical standalone pattern would match, if anchored at +the current point in the subject string. +</P> +<P> +Atomic grouping subpatterns are not capturing subpatterns. Simple cases such as +the above example can be thought of as a maximizing repeat that must swallow +everything it can. So, while both \d+ and \d+? are prepared to adjust the +number of digits they match in order to make the rest of the pattern match, +(?>\d+) can only match an entire sequence of digits. +</P> +<P> +Atomic groups in general can of course contain arbitrarily complicated +subpatterns, and can be nested. However, when the subpattern for an atomic +group is just a single repeated item, as in the example above, a simpler +notation, called a "possessive quantifier" can be used. This consists of an +additional + character following a quantifier. Using this notation, the +previous example can be rewritten as +<pre> + \d++foo +</pre> +Note that a possessive quantifier can be used with an entire group, for +example: +<pre> + (abc|xyz){2,3}+ +</pre> +Possessive quantifiers are always greedy; the setting of the PCRE_UNGREEDY +option is ignored. They are a convenient notation for the simpler forms of +atomic group. However, there is no difference in the meaning of a possessive +quantifier and the equivalent atomic group, though there may be a performance +difference; possessive quantifiers should be slightly faster. +</P> +<P> +The possessive quantifier syntax is an extension to the Perl 5.8 syntax. +Jeffrey Friedl originated the idea (and the name) in the first edition of his +book. Mike McCloskey liked it, so implemented it when he built Sun's Java +package, and PCRE copied it from there. It ultimately found its way into Perl +at release 5.10. +</P> +<P> +PCRE has an optimization that automatically "possessifies" certain simple +pattern constructs. For example, the sequence A+B is treated as A++B because +there is no point in backtracking into a sequence of A's when B must follow. +</P> +<P> +When a pattern contains an unlimited repeat inside a subpattern that can itself +be repeated an unlimited number of times, the use of an atomic group is the +only way to avoid some failing matches taking a very long time indeed. The +pattern +<pre> + (\D+|<\d+>)*[!?] +</pre> +matches an unlimited number of substrings that either consist of non-digits, or +digits enclosed in <>, followed by either ! or ?. When it matches, it runs +quickly. However, if it is applied to +<pre> + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +</pre> +it takes a long time before reporting failure. This is because the string can +be divided between the internal \D+ repeat and the external * repeat in a +large number of ways, and all have to be tried. (The example uses [!?] rather +than a single character at the end, because both PCRE and Perl have an +optimization that allows for fast failure when a single character is used. They +remember the last single character that is required for a match, and fail early +if it is not present in the string.) If the pattern is changed so that it uses +an atomic group, like this: +<pre> + ((?>\D+)|<\d+>)*[!?] +</pre> +sequences of non-digits cannot be broken, and failure happens quickly. +<a name="backreferences"></a></P> +<br><a name="SEC19" href="#TOC1">BACK REFERENCES</a><br> +<P> +Outside a character class, a backslash followed by a digit greater than 0 (and +possibly further digits) is a back reference to a capturing subpattern earlier +(that is, to its left) in the pattern, provided there have been that many +previous capturing left parentheses. +</P> +<P> +However, if the decimal number following the backslash is less than 10, it is +always taken as a back reference, and causes an error only if there are not +that many capturing left parentheses in the entire pattern. In other words, the +parentheses that are referenced need not be to the left of the reference for +numbers less than 10. A "forward back reference" of this type can make sense +when a repetition is involved and the subpattern to the right has participated +in an earlier iteration. +</P> +<P> +It is not possible to have a numerical "forward back reference" to a subpattern +whose number is 10 or more using this syntax because a sequence such as \50 is +interpreted as a character defined in octal. See the subsection entitled +"Non-printing characters" +<a href="#digitsafterbackslash">above</a> +for further details of the handling of digits following a backslash. There is +no such problem when named parentheses are used. A back reference to any +subpattern is possible using named parentheses (see below). +</P> +<P> +Another way of avoiding the ambiguity inherent in the use of digits following a +backslash is to use the \g escape sequence. This escape must be followed by an +unsigned number or a negative number, optionally enclosed in braces. These +examples are all identical: +<pre> + (ring), \1 + (ring), \g1 + (ring), \g{1} +</pre> +An unsigned number specifies an absolute reference without the ambiguity that +is present in the older syntax. It is also useful when literal digits follow +the reference. A negative number is a relative reference. Consider this +example: +<pre> + (abc(def)ghi)\g{-1} +</pre> +The sequence \g{-1} is a reference to the most recently started capturing +subpattern before \g, that is, is it equivalent to \2 in this example. +Similarly, \g{-2} would be equivalent to \1. The use of relative references +can be helpful in long patterns, and also in patterns that are created by +joining together fragments that contain references within themselves. +</P> +<P> +A back reference matches whatever actually matched the capturing subpattern in +the current subject string, rather than anything matching the subpattern +itself (see +<a href="#subpatternsassubroutines">"Subpatterns as subroutines"</a> +below for a way of doing that). So the pattern +<pre> + (sens|respons)e and \1ibility +</pre> +matches "sense and sensibility" and "response and responsibility", but not +"sense and responsibility". If caseful matching is in force at the time of the +back reference, the case of letters is relevant. For example, +<pre> + ((?i)rah)\s+\1 +</pre> +matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original +capturing subpattern is matched caselessly. +</P> +<P> +There are several different ways of writing back references to named +subpatterns. The .NET syntax \k{name} and the Perl syntax \k<name> or +\k'name' are supported, as is the Python syntax (?P=name). Perl 5.10's unified +back reference syntax, in which \g can be used for both numeric and named +references, is also supported. We could rewrite the above example in any of +the following ways: +<pre> + (?<p1>(?i)rah)\s+\k<p1> + (?'p1'(?i)rah)\s+\k{p1} + (?P<p1>(?i)rah)\s+(?P=p1) + (?<p1>(?i)rah)\s+\g{p1} +</pre> +A subpattern that is referenced by name may appear in the pattern before or +after the reference. +</P> +<P> +There may be more than one back reference to the same subpattern. If a +subpattern has not actually been used in a particular match, any back +references to it always fail by default. For example, the pattern +<pre> + (a|(bc))\2 +</pre> +always fails if it starts to match "a" rather than "bc". However, if the +PCRE_JAVASCRIPT_COMPAT option is set at compile time, a back reference to an +unset value matches an empty string. +</P> +<P> +Because there may be many capturing parentheses in a pattern, all digits +following a backslash are taken as part of a potential back reference number. +If the pattern continues with a digit character, some delimiter must be used to +terminate the back reference. If the PCRE_EXTENDED option is set, this can be +white space. Otherwise, the \g{ syntax or an empty comment (see +<a href="#comments">"Comments"</a> +below) can be used. +</P> +<br><b> +Recursive back references +</b><br> +<P> +A back reference that occurs inside the parentheses to which it refers fails +when the subpattern is first used, so, for example, (a\1) never matches. +However, such references can be useful inside repeated subpatterns. For +example, the pattern +<pre> + (a|b\1)+ +</pre> +matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of +the subpattern, the back reference matches the character string corresponding +to the previous iteration. In order for this to work, the pattern must be such +that the first iteration does not need to match the back reference. This can be +done using alternation, as in the example above, or by a quantifier with a +minimum of zero. +</P> +<P> +Back references of this type cause the group that they reference to be treated +as an +<a href="#atomicgroup">atomic group.</a> +Once the whole group has been matched, a subsequent matching failure cannot +cause backtracking into the middle of the group. +<a name="bigassertions"></a></P> +<br><a name="SEC20" href="#TOC1">ASSERTIONS</a><br> +<P> +An assertion is a test on the characters following or preceding the current +matching point that does not actually consume any characters. The simple +assertions coded as \b, \B, \A, \G, \Z, \z, ^ and $ are described +<a href="#smallassertions">above.</a> +</P> +<P> +More complicated assertions are coded as subpatterns. There are two kinds: +those that look ahead of the current position in the subject string, and those +that look behind it. An assertion subpattern is matched in the normal way, +except that it does not cause the current matching position to be changed. +</P> +<P> +Assertion subpatterns are not capturing subpatterns. If such an assertion +contains capturing subpatterns within it, these are counted for the purposes of +numbering the capturing subpatterns in the whole pattern. However, substring +capturing is carried out only for positive assertions. (Perl sometimes, but not +always, does do capturing in negative assertions.) +</P> +<P> +For compatibility with Perl, assertion subpatterns may be repeated; though +it makes no sense to assert the same thing several times, the side effect of +capturing parentheses may occasionally be useful. In practice, there only three +cases: +<br> +<br> +(1) If the quantifier is {0}, the assertion is never obeyed during matching. +However, it may contain internal capturing parenthesized groups that are called +from elsewhere via the +<a href="#subpatternsassubroutines">subroutine mechanism.</a> +<br> +<br> +(2) If quantifier is {0,n} where n is greater than zero, it is treated as if it +were {0,1}. At run time, the rest of the pattern match is tried with and +without the assertion, the order depending on the greediness of the quantifier. +<br> +<br> +(3) If the minimum repetition is greater than zero, the quantifier is ignored. +The assertion is obeyed just once when encountered during matching. +</P> +<br><b> +Lookahead assertions +</b><br> +<P> +Lookahead assertions start with (?= for positive assertions and (?! for +negative assertions. For example, +<pre> + \w+(?=;) +</pre> +matches a word followed by a semicolon, but does not include the semicolon in +the match, and +<pre> + foo(?!bar) +</pre> +matches any occurrence of "foo" that is not followed by "bar". Note that the +apparently similar pattern +<pre> + (?!foo)bar +</pre> +does not find an occurrence of "bar" that is preceded by something other than +"foo"; it finds any occurrence of "bar" whatsoever, because the assertion +(?!foo) is always true when the next three characters are "bar". A +lookbehind assertion is needed to achieve the other effect. +</P> +<P> +If you want to force a matching failure at some point in a pattern, the most +convenient way to do it is with (?!) because an empty string always matches, so +an assertion that requires there not to be an empty string must always fail. +The backtracking control verb (*FAIL) or (*F) is a synonym for (?!). +<a name="lookbehind"></a></P> +<br><b> +Lookbehind assertions +</b><br> +<P> +Lookbehind assertions start with (?<= for positive assertions and (?<! for +negative assertions. For example, +<pre> + (?<!foo)bar +</pre> +does find an occurrence of "bar" that is not preceded by "foo". The contents of +a lookbehind assertion are restricted such that all the strings it matches must +have a fixed length. However, if there are several top-level alternatives, they +do not all have to have the same fixed length. Thus +<pre> + (?<=bullock|donkey) +</pre> +is permitted, but +<pre> + (?<!dogs?|cats?) +</pre> +causes an error at compile time. Branches that match different length strings +are permitted only at the top level of a lookbehind assertion. This is an +extension compared with Perl, which requires all branches to match the same +length of string. An assertion such as +<pre> + (?<=ab(c|de)) +</pre> +is not permitted, because its single top-level branch can match two different +lengths, but it is acceptable to PCRE if rewritten to use two top-level +branches: +<pre> + (?<=abc|abde) +</pre> +In some cases, the escape sequence \K +<a href="#resetmatchstart">(see above)</a> +can be used instead of a lookbehind assertion to get round the fixed-length +restriction. +</P> +<P> +The implementation of lookbehind assertions is, for each alternative, to +temporarily move the current position back by the fixed length and then try to +match. If there are insufficient characters before the current position, the +assertion fails. +</P> +<P> +In a UTF mode, PCRE does not allow the \C escape (which matches a single data +unit even in a UTF mode) to appear in lookbehind assertions, because it makes +it impossible to calculate the length of the lookbehind. The \X and \R +escapes, which can match different numbers of data units, are also not +permitted. +</P> +<P> +<a href="#subpatternsassubroutines">"Subroutine"</a> +calls (see below) such as (?2) or (?&X) are permitted in lookbehinds, as long +as the subpattern matches a fixed-length string. +<a href="#recursion">Recursion,</a> +however, is not supported. +</P> +<P> +Possessive quantifiers can be used in conjunction with lookbehind assertions to +specify efficient matching of fixed-length strings at the end of subject +strings. Consider a simple pattern such as +<pre> + abcd$ +</pre> +when applied to a long string that does not match. Because matching proceeds +from left to right, PCRE will look for each "a" in the subject and then see if +what follows matches the rest of the pattern. If the pattern is specified as +<pre> + ^.*abcd$ +</pre> +the initial .* matches the entire string at first, but when this fails (because +there is no following "a"), it backtracks to match all but the last character, +then all but the last two characters, and so on. Once again the search for "a" +covers the entire string, from right to left, so we are no better off. However, +if the pattern is written as +<pre> + ^.*+(?<=abcd) +</pre> +there can be no backtracking for the .*+ item; it can match only the entire +string. The subsequent lookbehind assertion does a single test on the last four +characters. If it fails, the match fails immediately. For long strings, this +approach makes a significant difference to the processing time. +</P> +<br><b> +Using multiple assertions +</b><br> +<P> +Several assertions (of any sort) may occur in succession. For example, +<pre> + (?<=\d{3})(?<!999)foo +</pre> +matches "foo" preceded by three digits that are not "999". Notice that each of +the assertions is applied independently at the same point in the subject +string. First there is a check that the previous three characters are all +digits, and then there is a check that the same three characters are not "999". +This pattern does <i>not</i> match "foo" preceded by six characters, the first +of which are digits and the last three of which are not "999". For example, it +doesn't match "123abcfoo". A pattern to do that is +<pre> + (?<=\d{3}...)(?<!999)foo +</pre> +This time the first assertion looks at the preceding six characters, checking +that the first three are digits, and then the second assertion checks that the +preceding three characters are not "999". +</P> +<P> +Assertions can be nested in any combination. For example, +<pre> + (?<=(?<!foo)bar)baz +</pre> +matches an occurrence of "baz" that is preceded by "bar" which in turn is not +preceded by "foo", while +<pre> + (?<=\d{3}(?!999)...)foo +</pre> +is another pattern that matches "foo" preceded by three digits and any three +characters that are not "999". +<a name="conditions"></a></P> +<br><a name="SEC21" href="#TOC1">CONDITIONAL SUBPATTERNS</a><br> +<P> +It is possible to cause the matching process to obey a subpattern +conditionally or to choose between two alternative subpatterns, depending on +the result of an assertion, or whether a specific capturing subpattern has +already been matched. The two possible forms of conditional subpattern are: +<pre> + (?(condition)yes-pattern) + (?(condition)yes-pattern|no-pattern) +</pre> +If the condition is satisfied, the yes-pattern is used; otherwise the +no-pattern (if present) is used. If there are more than two alternatives in the +subpattern, a compile-time error occurs. Each of the two alternatives may +itself contain nested subpatterns of any form, including conditional +subpatterns; the restriction to two alternatives applies only at the level of +the condition. This pattern fragment is an example where the alternatives are +complex: +<pre> + (?(1) (A|B|C) | (D | (?(2)E|F) | E) ) + +</PRE> +</P> +<P> +There are four kinds of condition: references to subpatterns, references to +recursion, a pseudo-condition called DEFINE, and assertions. +</P> +<br><b> +Checking for a used subpattern by number +</b><br> +<P> +If the text between the parentheses consists of a sequence of digits, the +condition is true if a capturing subpattern of that number has previously +matched. If there is more than one capturing subpattern with the same number +(see the earlier +<a href="#recursion">section about duplicate subpattern numbers),</a> +the condition is true if any of them have matched. An alternative notation is +to precede the digits with a plus or minus sign. In this case, the subpattern +number is relative rather than absolute. The most recently opened parentheses +can be referenced by (?(-1), the next most recent by (?(-2), and so on. Inside +loops it can also make sense to refer to subsequent groups. The next +parentheses to be opened can be referenced as (?(+1), and so on. (The value +zero in any of these forms is not used; it provokes a compile-time error.) +</P> +<P> +Consider the following pattern, which contains non-significant white space to +make it more readable (assume the PCRE_EXTENDED option) and to divide it into +three parts for ease of discussion: +<pre> + ( \( )? [^()]+ (?(1) \) ) +</pre> +The first part matches an optional opening parenthesis, and if that +character is present, sets it as the first captured substring. The second part +matches one or more characters that are not parentheses. The third part is a +conditional subpattern that tests whether or not the first set of parentheses +matched. If they did, that is, if subject started with an opening parenthesis, +the condition is true, and so the yes-pattern is executed and a closing +parenthesis is required. Otherwise, since no-pattern is not present, the +subpattern matches nothing. In other words, this pattern matches a sequence of +non-parentheses, optionally enclosed in parentheses. +</P> +<P> +If you were embedding this pattern in a larger one, you could use a relative +reference: +<pre> + ...other stuff... ( \( )? [^()]+ (?(-1) \) ) ... +</pre> +This makes the fragment independent of the parentheses in the larger pattern. +</P> +<br><b> +Checking for a used subpattern by name +</b><br> +<P> +Perl uses the syntax (?(<name>)...) or (?('name')...) to test for a used +subpattern by name. For compatibility with earlier versions of PCRE, which had +this facility before Perl, the syntax (?(name)...) is also recognized. +</P> +<P> +Rewriting the above example to use a named subpattern gives this: +<pre> + (?<OPEN> \( )? [^()]+ (?(<OPEN>) \) ) +</pre> +If the name used in a condition of this kind is a duplicate, the test is +applied to all subpatterns of the same name, and is true if any one of them has +matched. +</P> +<br><b> +Checking for pattern recursion +</b><br> +<P> +If the condition is the string (R), and there is no subpattern with the name R, +the condition is true if a recursive call to the whole pattern or any +subpattern has been made. If digits or a name preceded by ampersand follow the +letter R, for example: +<pre> + (?(R3)...) or (?(R&name)...) +</pre> +the condition is true if the most recent recursion is into a subpattern whose +number or name is given. This condition does not check the entire recursion +stack. If the name used in a condition of this kind is a duplicate, the test is +applied to all subpatterns of the same name, and is true if any one of them is +the most recent recursion. +</P> +<P> +At "top level", all these recursion test conditions are false. +<a href="#recursion">The syntax for recursive patterns</a> +is described below. +<a name="subdefine"></a></P> +<br><b> +Defining subpatterns for use by reference only +</b><br> +<P> +If the condition is the string (DEFINE), and there is no subpattern with the +name DEFINE, the condition is always false. In this case, there may be only one +alternative in the subpattern. It is always skipped if control reaches this +point in the pattern; the idea of DEFINE is that it can be used to define +subroutines that can be referenced from elsewhere. (The use of +<a href="#subpatternsassubroutines">subroutines</a> +is described below.) For example, a pattern to match an IPv4 address such as +"192.168.23.245" could be written like this (ignore white space and line +breaks): +<pre> + (?(DEFINE) (?<byte> 2[0-4]\d | 25[0-5] | 1\d\d | [1-9]?\d) ) + \b (?&byte) (\.(?&byte)){3} \b +</pre> +The first part of the pattern is a DEFINE group inside which a another group +named "byte" is defined. This matches an individual component of an IPv4 +address (a number less than 256). When matching takes place, this part of the +pattern is skipped because DEFINE acts like a false condition. The rest of the +pattern uses references to the named group to match the four dot-separated +components of an IPv4 address, insisting on a word boundary at each end. +</P> +<br><b> +Assertion conditions +</b><br> +<P> +If the condition is not in any of the above formats, it must be an assertion. +This may be a positive or negative lookahead or lookbehind assertion. Consider +this pattern, again containing non-significant white space, and with the two +alternatives on the second line: +<pre> + (?(?=[^a-z]*[a-z]) + \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) +</pre> +The condition is a positive lookahead assertion that matches an optional +sequence of non-letters followed by a letter. In other words, it tests for the +presence of at least one letter in the subject. If a letter is found, the +subject is matched against the first alternative; otherwise it is matched +against the second. This pattern matches strings in one of the two forms +dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. +<a name="comments"></a></P> +<br><a name="SEC22" href="#TOC1">COMMENTS</a><br> +<P> +There are two ways of including comments in patterns that are processed by +PCRE. In both cases, the start of the comment must not be in a character class, +nor in the middle of any other sequence of related characters such as (?: or a +subpattern name or number. The characters that make up a comment play no part +in the pattern matching. +</P> +<P> +The sequence (?# marks the start of a comment that continues up to the next +closing parenthesis. Nested parentheses are not permitted. If the PCRE_EXTENDED +option is set, an unescaped # character also introduces a comment, which in +this case continues to immediately after the next newline character or +character sequence in the pattern. Which characters are interpreted as newlines +is controlled by the options passed to a compiling function or by a special +sequence at the start of the pattern, as described in the section entitled +<a href="#newlines">"Newline conventions"</a> +above. Note that the end of this type of comment is a literal newline sequence +in the pattern; escape sequences that happen to represent a newline do not +count. For example, consider this pattern when PCRE_EXTENDED is set, and the +default newline convention is in force: +<pre> + abc #comment \n still comment +</pre> +On encountering the # character, <b>pcre_compile()</b> skips along, looking for +a newline in the pattern. The sequence \n is still literal at this stage, so +it does not terminate the comment. Only an actual character with the code value +0x0a (the default newline) does so. +<a name="recursion"></a></P> +<br><a name="SEC23" href="#TOC1">RECURSIVE PATTERNS</a><br> +<P> +Consider the problem of matching a string in parentheses, allowing for +unlimited nested parentheses. Without the use of recursion, the best that can +be done is to use a pattern that matches up to some fixed depth of nesting. It +is not possible to handle an arbitrary nesting depth. +</P> +<P> +For some time, Perl has provided a facility that allows regular expressions to +recurse (amongst other things). It does this by interpolating Perl code in the +expression at run time, and the code can refer to the expression itself. A Perl +pattern using code interpolation to solve the parentheses problem can be +created like this: +<pre> + $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x; +</pre> +The (?p{...}) item interpolates Perl code at run time, and in this case refers +recursively to the pattern in which it appears. +</P> +<P> +Obviously, PCRE cannot support the interpolation of Perl code. Instead, it +supports special syntax for recursion of the entire pattern, and also for +individual subpattern recursion. After its introduction in PCRE and Python, +this kind of recursion was subsequently introduced into Perl at release 5.10. +</P> +<P> +A special item that consists of (? followed by a number greater than zero and a +closing parenthesis is a recursive subroutine call of the subpattern of the +given number, provided that it occurs inside that subpattern. (If not, it is a +<a href="#subpatternsassubroutines">non-recursive subroutine</a> +call, which is described in the next section.) The special item (?R) or (?0) is +a recursive call of the entire regular expression. +</P> +<P> +This PCRE pattern solves the nested parentheses problem (assume the +PCRE_EXTENDED option is set so that white space is ignored): +<pre> + \( ( [^()]++ | (?R) )* \) +</pre> +First it matches an opening parenthesis. Then it matches any number of +substrings which can either be a sequence of non-parentheses, or a recursive +match of the pattern itself (that is, a correctly parenthesized substring). +Finally there is a closing parenthesis. Note the use of a possessive quantifier +to avoid backtracking into sequences of non-parentheses. +</P> +<P> +If this were part of a larger pattern, you would not want to recurse the entire +pattern, so instead you could use this: +<pre> + ( \( ( [^()]++ | (?1) )* \) ) +</pre> +We have put the pattern into parentheses, and caused the recursion to refer to +them instead of the whole pattern. +</P> +<P> +In a larger pattern, keeping track of parenthesis numbers can be tricky. This +is made easier by the use of relative references. Instead of (?1) in the +pattern above you can write (?-2) to refer to the second most recently opened +parentheses preceding the recursion. In other words, a negative number counts +capturing parentheses leftwards from the point at which it is encountered. +</P> +<P> +It is also possible to refer to subsequently opened parentheses, by writing +references such as (?+2). However, these cannot be recursive because the +reference is not inside the parentheses that are referenced. They are always +<a href="#subpatternsassubroutines">non-recursive subroutine</a> +calls, as described in the next section. +</P> +<P> +An alternative approach is to use named parentheses instead. The Perl syntax +for this is (?&name); PCRE's earlier syntax (?P>name) is also supported. We +could rewrite the above example as follows: +<pre> + (?<pn> \( ( [^()]++ | (?&pn) )* \) ) +</pre> +If there is more than one subpattern with the same name, the earliest one is +used. +</P> +<P> +This particular example pattern that we have been looking at contains nested +unlimited repeats, and so the use of a possessive quantifier for matching +strings of non-parentheses is important when applying the pattern to strings +that do not match. For example, when this pattern is applied to +<pre> + (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() +</pre> +it yields "no match" quickly. However, if a possessive quantifier is not used, +the match runs for a very long time indeed because there are so many different +ways the + and * repeats can carve up the subject, and all have to be tested +before failure can be reported. +</P> +<P> +At the end of a match, the values of capturing parentheses are those from +the outermost level. If you want to obtain intermediate values, a callout +function can be used (see below and the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation). If the pattern above is matched against +<pre> + (ab(cd)ef) +</pre> +the value for the inner capturing parentheses (numbered 2) is "ef", which is +the last value taken on at the top level. If a capturing subpattern is not +matched at the top level, its final captured value is unset, even if it was +(temporarily) set at a deeper level during the matching process. +</P> +<P> +If there are more than 15 capturing parentheses in a pattern, PCRE has to +obtain extra memory to store data during a recursion, which it does by using +<b>pcre_malloc</b>, freeing it via <b>pcre_free</b> afterwards. If no memory can +be obtained, the match fails with the PCRE_ERROR_NOMEMORY error. +</P> +<P> +Do not confuse the (?R) item with the condition (R), which tests for recursion. +Consider this pattern, which matches text in angle brackets, allowing for +arbitrary nesting. Only digits are allowed in nested brackets (that is, when +recursing), whereas any characters are permitted at the outer level. +<pre> + < (?: (?(R) \d++ | [^<>]*+) | (?R)) * > +</pre> +In this pattern, (?(R) is the start of a conditional subpattern, with two +different alternatives for the recursive and non-recursive cases. The (?R) item +is the actual recursive call. +<a name="recursiondifference"></a></P> +<br><b> +Differences in recursion processing between PCRE and Perl +</b><br> +<P> +Recursion processing in PCRE differs from Perl in two important ways. In PCRE +(like Python, but unlike Perl), a recursive subpattern call is always treated +as an atomic group. That is, once it has matched some of the subject string, it +is never re-entered, even if it contains untried alternatives and there is a +subsequent matching failure. This can be illustrated by the following pattern, +which purports to match a palindromic string that contains an odd number of +characters (for example, "a", "aba", "abcba", "abcdcba"): +<pre> + ^(.|(.)(?1)\2)$ +</pre> +The idea is that it either matches a single character, or two identical +characters surrounding a sub-palindrome. In Perl, this pattern works; in PCRE +it does not if the pattern is longer than three characters. Consider the +subject string "abcba": +</P> +<P> +At the top level, the first character is matched, but as it is not at the end +of the string, the first alternative fails; the second alternative is taken +and the recursion kicks in. The recursive call to subpattern 1 successfully +matches the next character ("b"). (Note that the beginning and end of line +tests are not part of the recursion). +</P> +<P> +Back at the top level, the next character ("c") is compared with what +subpattern 2 matched, which was "a". This fails. Because the recursion is +treated as an atomic group, there are now no backtracking points, and so the +entire match fails. (Perl is able, at this point, to re-enter the recursion and +try the second alternative.) However, if the pattern is written with the +alternatives in the other order, things are different: +<pre> + ^((.)(?1)\2|.)$ +</pre> +This time, the recursing alternative is tried first, and continues to recurse +until it runs out of characters, at which point the recursion fails. But this +time we do have another alternative to try at the higher level. That is the big +difference: in the previous case the remaining alternative is at a deeper +recursion level, which PCRE cannot use. +</P> +<P> +To change the pattern so that it matches all palindromic strings, not just +those with an odd number of characters, it is tempting to change the pattern to +this: +<pre> + ^((.)(?1)\2|.?)$ +</pre> +Again, this works in Perl, but not in PCRE, and for the same reason. When a +deeper recursion has matched a single character, it cannot be entered again in +order to match an empty string. The solution is to separate the two cases, and +write out the odd and even cases as alternatives at the higher level: +<pre> + ^(?:((.)(?1)\2|)|((.)(?3)\4|.)) +</pre> +If you want to match typical palindromic phrases, the pattern has to ignore all +non-word characters, which can be done like this: +<pre> + ^\W*+(?:((.)\W*+(?1)\W*+\2|)|((.)\W*+(?3)\W*+\4|\W*+.\W*+))\W*+$ +</pre> +If run with the PCRE_CASELESS option, this pattern matches phrases such as "A +man, a plan, a canal: Panama!" and it works well in both PCRE and Perl. Note +the use of the possessive quantifier *+ to avoid backtracking into sequences of +non-word characters. Without this, PCRE takes a great deal longer (ten times or +more) to match typical phrases, and Perl takes so long that you think it has +gone into a loop. +</P> +<P> +<b>WARNING</b>: The palindrome-matching patterns above work only if the subject +string does not start with a palindrome that is shorter than the entire string. +For example, although "abcba" is correctly matched, if the subject is "ababa", +PCRE finds the palindrome "aba" at the start, then fails at top level because +the end of the string does not follow. Once again, it cannot jump back into the +recursion to try other alternatives, so the entire match fails. +</P> +<P> +The second way in which PCRE and Perl differ in their recursion processing is +in the handling of captured values. In Perl, when a subpattern is called +recursively or as a subpattern (see the next section), it has no access to any +values that were captured outside the recursion, whereas in PCRE these values +can be referenced. Consider this pattern: +<pre> + ^(.)(\1|a(?2)) +</pre> +In PCRE, this pattern matches "bab". The first capturing parentheses match "b", +then in the second group, when the back reference \1 fails to match "b", the +second alternative matches "a" and then recurses. In the recursion, \1 does +now match "b" and so the whole match succeeds. In Perl, the pattern fails to +match because inside the recursive call \1 cannot access the externally set +value. +<a name="subpatternsassubroutines"></a></P> +<br><a name="SEC24" href="#TOC1">SUBPATTERNS AS SUBROUTINES</a><br> +<P> +If the syntax for a recursive subpattern call (either by number or by +name) is used outside the parentheses to which it refers, it operates like a +subroutine in a programming language. The called subpattern may be defined +before or after the reference. A numbered reference can be absolute or +relative, as in these examples: +<pre> + (...(absolute)...)...(?2)... + (...(relative)...)...(?-1)... + (...(?+1)...(relative)... +</pre> +An earlier example pointed out that the pattern +<pre> + (sens|respons)e and \1ibility +</pre> +matches "sense and sensibility" and "response and responsibility", but not +"sense and responsibility". If instead the pattern +<pre> + (sens|respons)e and (?1)ibility +</pre> +is used, it does match "sense and responsibility" as well as the other two +strings. Another example is given in the discussion of DEFINE above. +</P> +<P> +All subroutine calls, whether recursive or not, are always treated as atomic +groups. That is, once a subroutine has matched some of the subject string, it +is never re-entered, even if it contains untried alternatives and there is a +subsequent matching failure. Any capturing parentheses that are set during the +subroutine call revert to their previous values afterwards. +</P> +<P> +Processing options such as case-independence are fixed when a subpattern is +defined, so if it is used as a subroutine, such options cannot be changed for +different calls. For example, consider this pattern: +<pre> + (abc)(?i:(?-1)) +</pre> +It matches "abcabc". It does not match "abcABC" because the change of +processing option does not affect the called subpattern. +<a name="onigurumasubroutines"></a></P> +<br><a name="SEC25" href="#TOC1">ONIGURUMA SUBROUTINE SYNTAX</a><br> +<P> +For compatibility with Oniguruma, the non-Perl syntax \g followed by a name or +a number enclosed either in angle brackets or single quotes, is an alternative +syntax for referencing a subpattern as a subroutine, possibly recursively. Here +are two of the examples used above, rewritten using this syntax: +<pre> + (?<pn> \( ( (?>[^()]+) | \g<pn> )* \) ) + (sens|respons)e and \g'1'ibility +</pre> +PCRE supports an extension to Oniguruma: if a number is preceded by a +plus or a minus sign it is taken as a relative reference. For example: +<pre> + (abc)(?i:\g<-1>) +</pre> +Note that \g{...} (Perl syntax) and \g<...> (Oniguruma syntax) are <i>not</i> +synonymous. The former is a back reference; the latter is a subroutine call. +</P> +<br><a name="SEC26" href="#TOC1">CALLOUTS</a><br> +<P> +Perl has a feature whereby using the sequence (?{...}) causes arbitrary Perl +code to be obeyed in the middle of matching a regular expression. This makes it +possible, amongst other things, to extract different substrings that match the +same pair of parentheses when there is a repetition. +</P> +<P> +PCRE provides a similar feature, but of course it cannot obey arbitrary Perl +code. The feature is called "callout". The caller of PCRE provides an external +function by putting its entry point in the global variable <i>pcre_callout</i> +(8-bit library) or <i>pcre[16|32]_callout</i> (16-bit or 32-bit library). +By default, this variable contains NULL, which disables all calling out. +</P> +<P> +Within a regular expression, (?C) indicates the points at which the external +function is to be called. If you want to identify different callout points, you +can put a number less than 256 after the letter C. The default value is zero. +For example, this pattern has two callout points: +<pre> + (?C1)abc(?C2)def +</pre> +If the PCRE_AUTO_CALLOUT flag is passed to a compiling function, callouts are +automatically installed before each item in the pattern. They are all numbered +255. If there is a conditional group in the pattern whose condition is an +assertion, an additional callout is inserted just before the condition. An +explicit callout may also be set at this position, as in this example: +<pre> + (?(?C9)(?=a)abc|def) +</pre> +Note that this applies only to assertion conditions, not to other types of +condition. +</P> +<P> +During matching, when PCRE reaches a callout point, the external function is +called. It is provided with the number of the callout, the position in the +pattern, and, optionally, one item of data originally supplied by the caller of +the matching function. The callout function may cause matching to proceed, to +backtrack, or to fail altogether. +</P> +<P> +By default, PCRE implements a number of optimizations at compile time and +matching time, and one side-effect is that sometimes callouts are skipped. If +you need all possible callouts to happen, you need to set options that disable +the relevant optimizations. More details, and a complete description of the +interface to the callout function, are given in the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +<a name="backtrackcontrol"></a></P> +<br><a name="SEC27" href="#TOC1">BACKTRACKING CONTROL</a><br> +<P> +Perl 5.10 introduced a number of "Special Backtracking Control Verbs", which +are still described in the Perl documentation as "experimental and subject to +change or removal in a future version of Perl". It goes on to say: "Their usage +in production code should be noted to avoid problems during upgrades." The same +remarks apply to the PCRE features described in this section. +</P> +<P> +The new verbs make use of what was previously invalid syntax: an opening +parenthesis followed by an asterisk. They are generally of the form +(*VERB) or (*VERB:NAME). Some may take either form, possibly behaving +differently depending on whether or not a name is present. A name is any +sequence of characters that does not include a closing parenthesis. The maximum +length of name is 255 in the 8-bit library and 65535 in the 16-bit and 32-bit +libraries. If the name is empty, that is, if the closing parenthesis +immediately follows the colon, the effect is as if the colon were not there. +Any number of these verbs may occur in a pattern. +</P> +<P> +Since these verbs are specifically related to backtracking, most of them can be +used only when the pattern is to be matched using one of the traditional +matching functions, because these use a backtracking algorithm. With the +exception of (*FAIL), which behaves like a failing negative assertion, the +backtracking control verbs cause an error if encountered by a DFA matching +function. +</P> +<P> +The behaviour of these verbs in +<a href="#btrepeat">repeated groups,</a> +<a href="#btassert">assertions,</a> +and in +<a href="#btsub">subpatterns called as subroutines</a> +(whether or not recursively) is documented below. +<a name="nooptimize"></a></P> +<br><b> +Optimizations that affect backtracking verbs +</b><br> +<P> +PCRE contains some optimizations that are used to speed up matching by running +some checks at the start of each match attempt. For example, it may know the +minimum length of matching subject, or that a particular character must be +present. When one of these optimizations bypasses the running of a match, any +included backtracking verbs will not, of course, be processed. You can suppress +the start-of-match optimizations by setting the PCRE_NO_START_OPTIMIZE option +when calling <b>pcre_compile()</b> or <b>pcre_exec()</b>, or by starting the +pattern with (*NO_START_OPT). There is more discussion of this option in the +section entitled +<a href="pcreapi.html#execoptions">"Option bits for <b>pcre_exec()</b>"</a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<P> +Experiments with Perl suggest that it too has similar optimizations, sometimes +leading to anomalous results. +</P> +<br><b> +Verbs that act immediately +</b><br> +<P> +The following verbs act as soon as they are encountered. They may not be +followed by a name. +<pre> + (*ACCEPT) +</pre> +This verb causes the match to end successfully, skipping the remainder of the +pattern. However, when it is inside a subpattern that is called as a +subroutine, only that subpattern is ended successfully. Matching then continues +at the outer level. If (*ACCEPT) in triggered in a positive assertion, the +assertion succeeds; in a negative assertion, the assertion fails. +</P> +<P> +If (*ACCEPT) is inside capturing parentheses, the data so far is captured. For +example: +<pre> + A((?:A|B(*ACCEPT)|C)D) +</pre> +This matches "AB", "AAD", or "ACD"; when it matches "AB", "B" is captured by +the outer parentheses. +<pre> + (*FAIL) or (*F) +</pre> +This verb causes a matching failure, forcing backtracking to occur. It is +equivalent to (?!) but easier to read. The Perl documentation notes that it is +probably useful only when combined with (?{}) or (??{}). Those are, of course, +Perl features that are not present in PCRE. The nearest equivalent is the +callout feature, as for example in this pattern: +<pre> + a+(?C)(*FAIL) +</pre> +A match with the string "aaaa" always fails, but the callout is taken before +each backtrack happens (in this example, 10 times). +</P> +<br><b> +Recording which path was taken +</b><br> +<P> +There is one verb whose main purpose is to track how a match was arrived at, +though it also has a secondary use in conjunction with advancing the match +starting point (see (*SKIP) below). +<pre> + (*MARK:NAME) or (*:NAME) +</pre> +A name is always required with this verb. There may be as many instances of +(*MARK) as you like in a pattern, and their names do not have to be unique. +</P> +<P> +When a match succeeds, the name of the last-encountered (*MARK:NAME), +(*PRUNE:NAME), or (*THEN:NAME) on the matching path is passed back to the +caller as described in the section entitled +<a href="pcreapi.html#extradata">"Extra data for <b>pcre_exec()</b>"</a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. Here is an example of <b>pcretest</b> output, where the /K +modifier requests the retrieval and outputting of (*MARK) data: +<pre> + re> /X(*MARK:A)Y|X(*MARK:B)Z/K + data> XY + 0: XY + MK: A + XZ + 0: XZ + MK: B +</pre> +The (*MARK) name is tagged with "MK:" in this output, and in this example it +indicates which of the two alternatives matched. This is a more efficient way +of obtaining this information than putting each alternative in its own +capturing parentheses. +</P> +<P> +If a verb with a name is encountered in a positive assertion that is true, the +name is recorded and passed back if it is the last-encountered. This does not +happen for negative assertions or failing positive assertions. +</P> +<P> +After a partial match or a failed match, the last encountered name in the +entire match process is returned. For example: +<pre> + re> /X(*MARK:A)Y|X(*MARK:B)Z/K + data> XP + No match, mark = B +</pre> +Note that in this unanchored example the mark is retained from the match +attempt that started at the letter "X" in the subject. Subsequent match +attempts starting at "P" and then with an empty string do not get as far as the +(*MARK) item, but nevertheless do not reset it. +</P> +<P> +If you are interested in (*MARK) values after failed matches, you should +probably set the PCRE_NO_START_OPTIMIZE option +<a href="#nooptimize">(see above)</a> +to ensure that the match is always attempted. +</P> +<br><b> +Verbs that act after backtracking +</b><br> +<P> +The following verbs do nothing when they are encountered. Matching continues +with what follows, but if there is no subsequent match, causing a backtrack to +the verb, a failure is forced. That is, backtracking cannot pass to the left of +the verb. However, when one of these verbs appears inside an atomic group or an +assertion that is true, its effect is confined to that group, because once the +group has been matched, there is never any backtracking into it. In this +situation, backtracking can "jump back" to the left of the entire atomic group +or assertion. (Remember also, as stated above, that this localization also +applies in subroutine calls.) +</P> +<P> +These verbs differ in exactly what kind of failure occurs when backtracking +reaches them. The behaviour described below is what happens when the verb is +not in a subroutine or an assertion. Subsequent sections cover these special +cases. +<pre> + (*COMMIT) +</pre> +This verb, which may not be followed by a name, causes the whole match to fail +outright if there is a later matching failure that causes backtracking to reach +it. Even if the pattern is unanchored, no further attempts to find a match by +advancing the starting point take place. If (*COMMIT) is the only backtracking +verb that is encountered, once it has been passed <b>pcre_exec()</b> is +committed to finding a match at the current starting point, or not at all. For +example: +<pre> + a+(*COMMIT)b +</pre> +This matches "xxaab" but not "aacaab". It can be thought of as a kind of +dynamic anchor, or "I've started, so I must finish." The name of the most +recently passed (*MARK) in the path is passed back when (*COMMIT) forces a +match failure. +</P> +<P> +If there is more than one backtracking verb in a pattern, a different one that +follows (*COMMIT) may be triggered first, so merely passing (*COMMIT) during a +match does not always guarantee that a match must be at this starting point. +</P> +<P> +Note that (*COMMIT) at the start of a pattern is not the same as an anchor, +unless PCRE's start-of-match optimizations are turned off, as shown in this +output from <b>pcretest</b>: +<pre> + re> /(*COMMIT)abc/ + data> xyzabc + 0: abc + data> xyzabc\Y + No match +</pre> +For this pattern, PCRE knows that any match must start with "a", so the +optimization skips along the subject to "a" before applying the pattern to the +first set of data. The match attempt then succeeds. In the second set of data, +the escape sequence \Y is interpreted by the <b>pcretest</b> program. It causes +the PCRE_NO_START_OPTIMIZE option to be set when <b>pcre_exec()</b> is called. +This disables the optimization that skips along to the first character. The +pattern is now applied starting at "x", and so the (*COMMIT) causes the match +to fail without trying any other starting points. +<pre> + (*PRUNE) or (*PRUNE:NAME) +</pre> +This verb causes the match to fail at the current starting position in the +subject if there is a later matching failure that causes backtracking to reach +it. If the pattern is unanchored, the normal "bumpalong" advance to the next +starting character then happens. Backtracking can occur as usual to the left of +(*PRUNE), before it is reached, or when matching to the right of (*PRUNE), but +if there is no match to the right, backtracking cannot cross (*PRUNE). In +simple cases, the use of (*PRUNE) is just an alternative to an atomic group or +possessive quantifier, but there are some uses of (*PRUNE) that cannot be +expressed in any other way. In an anchored pattern (*PRUNE) has the same effect +as (*COMMIT). +</P> +<P> +The behaviour of (*PRUNE:NAME) is the not the same as (*MARK:NAME)(*PRUNE). +It is like (*MARK:NAME) in that the name is remembered for passing back to the +caller. However, (*SKIP:NAME) searches only for names set with (*MARK). +<pre> + (*SKIP) +</pre> +This verb, when given without a name, is like (*PRUNE), except that if the +pattern is unanchored, the "bumpalong" advance is not to the next character, +but to the position in the subject where (*SKIP) was encountered. (*SKIP) +signifies that whatever text was matched leading up to it cannot be part of a +successful match. Consider: +<pre> + a+(*SKIP)b +</pre> +If the subject is "aaaac...", after the first match attempt fails (starting at +the first character in the string), the starting point skips on to start the +next attempt at "c". Note that a possessive quantifer does not have the same +effect as this example; although it would suppress backtracking during the +first match attempt, the second attempt would start at the second character +instead of skipping on to "c". +<pre> + (*SKIP:NAME) +</pre> +When (*SKIP) has an associated name, its behaviour is modified. When it is +triggered, the previous path through the pattern is searched for the most +recent (*MARK) that has the same name. If one is found, the "bumpalong" advance +is to the subject position that corresponds to that (*MARK) instead of to where +(*SKIP) was encountered. If no (*MARK) with a matching name is found, the +(*SKIP) is ignored. +</P> +<P> +Note that (*SKIP:NAME) searches only for names set by (*MARK:NAME). It ignores +names that are set by (*PRUNE:NAME) or (*THEN:NAME). +<pre> + (*THEN) or (*THEN:NAME) +</pre> +This verb causes a skip to the next innermost alternative when backtracking +reaches it. That is, it cancels any further backtracking within the current +alternative. Its name comes from the observation that it can be used for a +pattern-based if-then-else block: +<pre> + ( COND1 (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ ) ... +</pre> +If the COND1 pattern matches, FOO is tried (and possibly further items after +the end of the group if FOO succeeds); on failure, the matcher skips to the +second alternative and tries COND2, without backtracking into COND1. If that +succeeds and BAR fails, COND3 is tried. If subsequently BAZ fails, there are no +more alternatives, so there is a backtrack to whatever came before the entire +group. If (*THEN) is not inside an alternation, it acts like (*PRUNE). +</P> +<P> +The behaviour of (*THEN:NAME) is the not the same as (*MARK:NAME)(*THEN). +It is like (*MARK:NAME) in that the name is remembered for passing back to the +caller. However, (*SKIP:NAME) searches only for names set with (*MARK). +</P> +<P> +A subpattern that does not contain a | character is just a part of the +enclosing alternative; it is not a nested alternation with only one +alternative. The effect of (*THEN) extends beyond such a subpattern to the +enclosing alternative. Consider this pattern, where A, B, etc. are complex +pattern fragments that do not contain any | characters at this level: +<pre> + A (B(*THEN)C) | D +</pre> +If A and B are matched, but there is a failure in C, matching does not +backtrack into A; instead it moves to the next alternative, that is, D. +However, if the subpattern containing (*THEN) is given an alternative, it +behaves differently: +<pre> + A (B(*THEN)C | (*FAIL)) | D +</pre> +The effect of (*THEN) is now confined to the inner subpattern. After a failure +in C, matching moves to (*FAIL), which causes the whole subpattern to fail +because there are no more alternatives to try. In this case, matching does now +backtrack into A. +</P> +<P> +Note that a conditional subpattern is not considered as having two +alternatives, because only one is ever used. In other words, the | character in +a conditional subpattern has a different meaning. Ignoring white space, +consider: +<pre> + ^.*? (?(?=a) a | b(*THEN)c ) +</pre> +If the subject is "ba", this pattern does not match. Because .*? is ungreedy, +it initially matches zero characters. The condition (?=a) then fails, the +character "b" is matched, but "c" is not. At this point, matching does not +backtrack to .*? as might perhaps be expected from the presence of the | +character. The conditional subpattern is part of the single alternative that +comprises the whole pattern, and so the match fails. (If there was a backtrack +into .*?, allowing it to match "b", the match would succeed.) +</P> +<P> +The verbs just described provide four different "strengths" of control when +subsequent matching fails. (*THEN) is the weakest, carrying on the match at the +next alternative. (*PRUNE) comes next, failing the match at the current +starting position, but allowing an advance to the next character (for an +unanchored pattern). (*SKIP) is similar, except that the advance may be more +than one character. (*COMMIT) is the strongest, causing the entire match to +fail. +</P> +<br><b> +More than one backtracking verb +</b><br> +<P> +If more than one backtracking verb is present in a pattern, the one that is +backtracked onto first acts. For example, consider this pattern, where A, B, +etc. are complex pattern fragments: +<pre> + (A(*COMMIT)B(*THEN)C|ABD) +</pre> +If A matches but B fails, the backtrack to (*COMMIT) causes the entire match to +fail. However, if A and B match, but C fails, the backtrack to (*THEN) causes +the next alternative (ABD) to be tried. This behaviour is consistent, but is +not always the same as Perl's. It means that if two or more backtracking verbs +appear in succession, all the the last of them has no effect. Consider this +example: +<pre> + ...(*COMMIT)(*PRUNE)... +</pre> +If there is a matching failure to the right, backtracking onto (*PRUNE) causes +it to be triggered, and its action is taken. There can never be a backtrack +onto (*COMMIT). +<a name="btrepeat"></a></P> +<br><b> +Backtracking verbs in repeated groups +</b><br> +<P> +PCRE differs from Perl in its handling of backtracking verbs in repeated +groups. For example, consider: +<pre> + /(a(*COMMIT)b)+ac/ +</pre> +If the subject is "abac", Perl matches, but PCRE fails because the (*COMMIT) in +the second repeat of the group acts. +<a name="btassert"></a></P> +<br><b> +Backtracking verbs in assertions +</b><br> +<P> +(*FAIL) in an assertion has its normal effect: it forces an immediate backtrack. +</P> +<P> +(*ACCEPT) in a positive assertion causes the assertion to succeed without any +further processing. In a negative assertion, (*ACCEPT) causes the assertion to +fail without any further processing. +</P> +<P> +The other backtracking verbs are not treated specially if they appear in a +positive assertion. In particular, (*THEN) skips to the next alternative in the +innermost enclosing group that has alternations, whether or not this is within +the assertion. +</P> +<P> +Negative assertions are, however, different, in order to ensure that changing a +positive assertion into a negative assertion changes its result. Backtracking +into (*COMMIT), (*SKIP), or (*PRUNE) causes a negative assertion to be true, +without considering any further alternative branches in the assertion. +Backtracking into (*THEN) causes it to skip to the next enclosing alternative +within the assertion (the normal behaviour), but if the assertion does not have +such an alternative, (*THEN) behaves like (*PRUNE). +<a name="btsub"></a></P> +<br><b> +Backtracking verbs in subroutines +</b><br> +<P> +These behaviours occur whether or not the subpattern is called recursively. +Perl's treatment of subroutines is different in some cases. +</P> +<P> +(*FAIL) in a subpattern called as a subroutine has its normal effect: it forces +an immediate backtrack. +</P> +<P> +(*ACCEPT) in a subpattern called as a subroutine causes the subroutine match to +succeed without any further processing. Matching then continues after the +subroutine call. +</P> +<P> +(*COMMIT), (*SKIP), and (*PRUNE) in a subpattern called as a subroutine cause +the subroutine match to fail. +</P> +<P> +(*THEN) skips to the next alternative in the innermost enclosing group within +the subpattern that has alternatives. If there is no such group within the +subpattern, (*THEN) causes the subroutine match to fail. +</P> +<br><a name="SEC28" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3), +<b>pcresyntax</b>(3), <b>pcre</b>(3), <b>pcre16(3)</b>, <b>pcre32(3)</b>. +</P> +<br><a name="SEC29" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC30" href="#TOC1">REVISION</a><br> +<P> +Last updated: 08 January 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcreperform.html b/doc/html/pcreperform.html new file mode 100644 index 0000000..dda207f --- /dev/null +++ b/doc/html/pcreperform.html @@ -0,0 +1,195 @@ +<html> +<head> +<title>pcreperform specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcreperform man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +PCRE PERFORMANCE +</b><br> +<P> +Two aspects of performance are discussed below: memory usage and processing +time. The way you express your pattern as a regular expression can affect both +of them. +</P> +<br><b> +COMPILED PATTERN MEMORY USAGE +</b><br> +<P> +Patterns are compiled by PCRE into a reasonably efficient interpretive code, so +that most simple patterns do not use much memory. However, there is one case +where the memory usage of a compiled pattern can be unexpectedly large. If a +parenthesized subpattern has a quantifier with a minimum greater than 1 and/or +a limited maximum, the whole subpattern is repeated in the compiled code. For +example, the pattern +<pre> + (abc|def){2,4} +</pre> +is compiled as if it were +<pre> + (abc|def)(abc|def)((abc|def)(abc|def)?)? +</pre> +(Technical aside: It is done this way so that backtrack points within each of +the repetitions can be independently maintained.) +</P> +<P> +For regular expressions whose quantifiers use only small numbers, this is not +usually a problem. However, if the numbers are large, and particularly if such +repetitions are nested, the memory usage can become an embarrassment. For +example, the very simple pattern +<pre> + ((ab){1,1000}c){1,3} +</pre> +uses 51K bytes when compiled using the 8-bit library. When PCRE is compiled +with its default internal pointer size of two bytes, the size limit on a +compiled pattern is 64K data units, and this is reached with the above pattern +if the outer repetition is increased from 3 to 4. PCRE can be compiled to use +larger internal pointers and thus handle larger compiled patterns, but it is +better to try to rewrite your pattern to use less memory if you can. +</P> +<P> +One way of reducing the memory usage for such patterns is to make use of PCRE's +<a href="pcrepattern.html#subpatternsassubroutines">"subroutine"</a> +facility. Re-writing the above pattern as +<pre> + ((ab)(?2){0,999}c)(?1){0,2} +</pre> +reduces the memory requirements to 18K, and indeed it remains under 20K even +with the outer repetition increased to 100. However, this pattern is not +exactly equivalent, because the "subroutine" calls are treated as +<a href="pcrepattern.html#atomicgroup">atomic groups</a> +into which there can be no backtracking if there is a subsequent matching +failure. Therefore, PCRE cannot do this kind of rewriting automatically. +Furthermore, there is a noticeable loss of speed when executing the modified +pattern. Nevertheless, if the atomic grouping is not a problem and the loss of +speed is acceptable, this kind of rewriting will allow you to process patterns +that PCRE cannot otherwise handle. +</P> +<br><b> +STACK USAGE AT RUN TIME +</b><br> +<P> +When <b>pcre_exec()</b> or <b>pcre[16|32]_exec()</b> is used for matching, certain +kinds of pattern can cause it to use large amounts of the process stack. In +some environments the default process stack is quite small, and if it runs out +the result is often SIGSEGV. This issue is probably the most frequently raised +problem with PCRE. Rewriting your pattern can often help. The +<a href="pcrestack.html"><b>pcrestack</b></a> +documentation discusses this issue in detail. +</P> +<br><b> +PROCESSING TIME +</b><br> +<P> +Certain items in regular expression patterns are processed more efficiently +than others. It is more efficient to use a character class like [aeiou] than a +set of single-character alternatives such as (a|e|i|o|u). In general, the +simplest construction that provides the required behaviour is usually the most +efficient. Jeffrey Friedl's book contains a lot of useful general discussion +about optimizing regular expressions for efficient performance. This document +contains a few observations about PCRE. +</P> +<P> +Using Unicode character properties (the \p, \P, and \X escapes) is slow, +because PCRE has to use a multi-stage table lookup whenever it needs a +character's property. If you can find an alternative pattern that does not use +character properties, it will probably be faster. +</P> +<P> +By default, the escape sequences \b, \d, \s, and \w, and the POSIX +character classes such as [:alpha:] do not use Unicode properties, partly for +backwards compatibility, and partly for performance reasons. However, you can +set PCRE_UCP if you want Unicode character properties to be used. This can +double the matching time for items such as \d, when matched with +a traditional matching function; the performance loss is less with +a DFA matching function, and in both cases there is not much difference for +\b. +</P> +<P> +When a pattern begins with .* not in parentheses, or in parentheses that are +not the subject of a backreference, and the PCRE_DOTALL option is set, the +pattern is implicitly anchored by PCRE, since it can match only at the start of +a subject string. However, if PCRE_DOTALL is not set, PCRE cannot make this +optimization, because the . metacharacter does not then match a newline, and if +the subject string contains newlines, the pattern may match from the character +immediately following one of them instead of from the very start. For example, +the pattern +<pre> + .*second +</pre> +matches the subject "first\nand second" (where \n stands for a newline +character), with the match starting at the seventh character. In order to do +this, PCRE has to retry the match starting after every newline in the subject. +</P> +<P> +If you are using such a pattern with subject strings that do not contain +newlines, the best performance is obtained by setting PCRE_DOTALL, or starting +the pattern with ^.* or ^.*? to indicate explicit anchoring. That saves PCRE +from having to scan along the subject looking for a newline to restart at. +</P> +<P> +Beware of patterns that contain nested indefinite repeats. These can take a +long time to run when applied to a string that does not match. Consider the +pattern fragment +<pre> + ^(a+)* +</pre> +This can match "aaaa" in 16 different ways, and this number increases very +rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4 +times, and for each of those cases other than 0 or 4, the + repeats can match +different numbers of times.) When the remainder of the pattern is such that the +entire match is going to fail, PCRE has in principle to try every possible +variation, and this can take an extremely long time, even for relatively short +strings. +</P> +<P> +An optimization catches some of the more simple cases such as +<pre> + (a+)*b +</pre> +where a literal character follows. Before embarking on the standard matching +procedure, PCRE checks that there is a "b" later in the subject string, and if +there is not, it fails the match immediately. However, when there is no +following literal this optimization cannot be used. You can see the difference +by comparing the behaviour of +<pre> + (a+)*\d +</pre> +with the pattern above. The former gives a failure almost instantly when +applied to a whole line of "a" characters, whereas the latter takes an +appreciable time with strings longer than about 20 characters. +</P> +<P> +In many cases, the solution to this kind of performance issue is to use an +atomic group or a possessive quantifier. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 25 August 2012 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcreposix.html b/doc/html/pcreposix.html new file mode 100644 index 0000000..18924cf --- /dev/null +++ b/doc/html/pcreposix.html @@ -0,0 +1,290 @@ +<html> +<head> +<title>pcreposix specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcreposix man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> +<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> +<li><a name="TOC3" href="#SEC3">COMPILING A PATTERN</a> +<li><a name="TOC4" href="#SEC4">MATCHING NEWLINE CHARACTERS</a> +<li><a name="TOC5" href="#SEC5">MATCHING A PATTERN</a> +<li><a name="TOC6" href="#SEC6">ERROR MESSAGES</a> +<li><a name="TOC7" href="#SEC7">MEMORY USAGE</a> +<li><a name="TOC8" href="#SEC8">AUTHOR</a> +<li><a name="TOC9" href="#SEC9">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> +<P> +<b>#include <pcreposix.h></b> +</P> +<P> +<b>int regcomp(regex_t *<i>preg</i>, const char *<i>pattern</i>,</b> +<b> int <i>cflags</i>);</b> +<br> +<br> +<b>int regexec(regex_t *<i>preg</i>, const char *<i>string</i>,</b> +<b> size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b> +<b> size_t regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b> +<b> char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b> +<br> +<br> +<b>void regfree(regex_t *<i>preg</i>);</b> +</P> +<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> +<P> +This set of functions provides a POSIX-style API for the PCRE regular +expression 8-bit library. See the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation for a description of PCRE's native API, which contains much +additional functionality. There is no POSIX-style wrapper for PCRE's 16-bit +and 32-bit library. +</P> +<P> +The functions described here are just wrapper functions that ultimately call +the PCRE native API. Their prototypes are defined in the <b>pcreposix.h</b> +header file, and on Unix systems the library itself is called +<b>pcreposix.a</b>, so can be accessed by adding <b>-lpcreposix</b> to the +command for linking an application that uses them. Because the POSIX functions +call the native ones, it is also necessary to add <b>-lpcre</b>. +</P> +<P> +I have implemented only those POSIX option bits that can be reasonably mapped +to PCRE native options. In addition, the option REG_EXTENDED is defined with +the value zero. This has no effect, but since programs that are written to the +POSIX interface often use it, this makes it easier to slot in PCRE as a +replacement library. Other POSIX options are not even defined. +</P> +<P> +There are also some other options that are not defined by POSIX. These have +been added at the request of users who want to make use of certain +PCRE-specific features via the POSIX calling interface. +</P> +<P> +When PCRE is called via these functions, it is only the API that is POSIX-like +in style. The syntax and semantics of the regular expressions themselves are +still those of Perl, subject to the setting of various PCRE options, as +described below. "POSIX-like in style" means that the API approximates to the +POSIX definition; it is not fully POSIX-compatible, and in multi-byte encoding +domains it is probably even less compatible. +</P> +<P> +The header for these functions is supplied as <b>pcreposix.h</b> to avoid any +potential clash with other POSIX libraries. It can, of course, be renamed or +aliased as <b>regex.h</b>, which is the "correct" name. It provides two +structure types, <i>regex_t</i> for compiled internal forms, and +<i>regmatch_t</i> for returning captured substrings. It also defines some +constants whose names start with "REG_"; these are used for setting options and +identifying error codes. +</P> +<br><a name="SEC3" href="#TOC1">COMPILING A PATTERN</a><br> +<P> +The function <b>regcomp()</b> is called to compile a pattern into an +internal form. The pattern is a C string terminated by a binary zero, and +is passed in the argument <i>pattern</i>. The <i>preg</i> argument is a pointer +to a <b>regex_t</b> structure that is used as a base for storing information +about the compiled regular expression. +</P> +<P> +The argument <i>cflags</i> is either zero, or contains one or more of the bits +defined by the following macros: +<pre> + REG_DOTALL +</pre> +The PCRE_DOTALL option is set when the regular expression is passed for +compilation to the native function. Note that REG_DOTALL is not part of the +POSIX standard. +<pre> + REG_ICASE +</pre> +The PCRE_CASELESS option is set when the regular expression is passed for +compilation to the native function. +<pre> + REG_NEWLINE +</pre> +The PCRE_MULTILINE option is set when the regular expression is passed for +compilation to the native function. Note that this does <i>not</i> mimic the +defined POSIX behaviour for REG_NEWLINE (see the following section). +<pre> + REG_NOSUB +</pre> +The PCRE_NO_AUTO_CAPTURE option is set when the regular expression is passed +for compilation to the native function. In addition, when a pattern that is +compiled with this flag is passed to <b>regexec()</b> for matching, the +<i>nmatch</i> and <i>pmatch</i> arguments are ignored, and no captured strings +are returned. +<pre> + REG_UCP +</pre> +The PCRE_UCP option is set when the regular expression is passed for +compilation to the native function. This causes PCRE to use Unicode properties +when matchine \d, \w, etc., instead of just recognizing ASCII values. Note +that REG_UTF8 is not part of the POSIX standard. +<pre> + REG_UNGREEDY +</pre> +The PCRE_UNGREEDY option is set when the regular expression is passed for +compilation to the native function. Note that REG_UNGREEDY is not part of the +POSIX standard. +<pre> + REG_UTF8 +</pre> +The PCRE_UTF8 option is set when the regular expression is passed for +compilation to the native function. This causes the pattern itself and all data +strings used for matching it to be treated as UTF-8 strings. Note that REG_UTF8 +is not part of the POSIX standard. +</P> +<P> +In the absence of these flags, no options are passed to the native function. +This means the the regex is compiled with PCRE default semantics. In +particular, the way it handles newline characters in the subject string is the +Perl way, not the POSIX way. Note that setting PCRE_MULTILINE has only +<i>some</i> of the effects specified for REG_NEWLINE. It does not affect the way +newlines are matched by . (they are not) or by a negative class such as [^a] +(they are). +</P> +<P> +The yield of <b>regcomp()</b> is zero on success, and non-zero otherwise. The +<i>preg</i> structure is filled in on success, and one member of the structure +is public: <i>re_nsub</i> contains the number of capturing subpatterns in +the regular expression. Various error codes are defined in the header file. +</P> +<P> +NOTE: If the yield of <b>regcomp()</b> is non-zero, you must not attempt to +use the contents of the <i>preg</i> structure. If, for example, you pass it to +<b>regexec()</b>, the result is undefined and your program is likely to crash. +</P> +<br><a name="SEC4" href="#TOC1">MATCHING NEWLINE CHARACTERS</a><br> +<P> +This area is not simple, because POSIX and Perl take different views of things. +It is not possible to get PCRE to obey POSIX semantics, but then PCRE was never +intended to be a POSIX engine. The following table lists the different +possibilities for matching newline characters in PCRE: +<pre> + Default Change with + + . matches newline no PCRE_DOTALL + newline matches [^a] yes not changeable + $ matches \n at end yes PCRE_DOLLARENDONLY + $ matches \n in middle no PCRE_MULTILINE + ^ matches \n in middle no PCRE_MULTILINE +</pre> +This is the equivalent table for POSIX: +<pre> + Default Change with + + . matches newline yes REG_NEWLINE + newline matches [^a] yes REG_NEWLINE + $ matches \n at end no REG_NEWLINE + $ matches \n in middle no REG_NEWLINE + ^ matches \n in middle no REG_NEWLINE +</pre> +PCRE's behaviour is the same as Perl's, except that there is no equivalent for +PCRE_DOLLAR_ENDONLY in Perl. In both PCRE and Perl, there is no way to stop +newline from matching [^a]. +</P> +<P> +The default POSIX newline handling can be obtained by setting PCRE_DOTALL and +PCRE_DOLLAR_ENDONLY, but there is no way to make PCRE behave exactly as for the +REG_NEWLINE action. +</P> +<br><a name="SEC5" href="#TOC1">MATCHING A PATTERN</a><br> +<P> +The function <b>regexec()</b> is called to match a compiled pattern <i>preg</i> +against a given <i>string</i>, which is by default terminated by a zero byte +(but see REG_STARTEND below), subject to the options in <i>eflags</i>. These can +be: +<pre> + REG_NOTBOL +</pre> +The PCRE_NOTBOL option is set when calling the underlying PCRE matching +function. +<pre> + REG_NOTEMPTY +</pre> +The PCRE_NOTEMPTY option is set when calling the underlying PCRE matching +function. Note that REG_NOTEMPTY is not part of the POSIX standard. However, +setting this option can give more POSIX-like behaviour in some situations. +<pre> + REG_NOTEOL +</pre> +The PCRE_NOTEOL option is set when calling the underlying PCRE matching +function. +<pre> + REG_STARTEND +</pre> +The string is considered to start at <i>string</i> + <i>pmatch[0].rm_so</i> and +to have a terminating NUL located at <i>string</i> + <i>pmatch[0].rm_eo</i> +(there need not actually be a NUL at that location), regardless of the value of +<i>nmatch</i>. This is a BSD extension, compatible with but not specified by +IEEE Standard 1003.2 (POSIX.2), and should be used with caution in software +intended to be portable to other systems. Note that a non-zero <i>rm_so</i> does +not imply REG_NOTBOL; REG_STARTEND affects only the location of the string, not +how it is matched. +</P> +<P> +If the pattern was compiled with the REG_NOSUB flag, no data about any matched +strings is returned. The <i>nmatch</i> and <i>pmatch</i> arguments of +<b>regexec()</b> are ignored. +</P> +<P> +If the value of <i>nmatch</i> is zero, or if the value <i>pmatch</i> is NULL, +no data about any matched strings is returned. +</P> +<P> +Otherwise,the portion of the string that was matched, and also any captured +substrings, are returned via the <i>pmatch</i> argument, which points to an +array of <i>nmatch</i> structures of type <i>regmatch_t</i>, containing the +members <i>rm_so</i> and <i>rm_eo</i>. These contain the offset to the first +character of each substring and the offset to the first character after the end +of each substring, respectively. The 0th element of the vector relates to the +entire portion of <i>string</i> that was matched; subsequent elements relate to +the capturing subpatterns of the regular expression. Unused entries in the +array have both structure members set to -1. +</P> +<P> +A successful match yields a zero return; various error codes are defined in the +header file, of which REG_NOMATCH is the "expected" failure code. +</P> +<br><a name="SEC6" href="#TOC1">ERROR MESSAGES</a><br> +<P> +The <b>regerror()</b> function maps a non-zero errorcode from either +<b>regcomp()</b> or <b>regexec()</b> to a printable message. If <i>preg</i> is not +NULL, the error should have arisen from the use of that structure. A message +terminated by a binary zero is placed in <i>errbuf</i>. The length of the +message, including the zero, is limited to <i>errbuf_size</i>. The yield of the +function is the size of buffer needed to hold the whole message. +</P> +<br><a name="SEC7" href="#TOC1">MEMORY USAGE</a><br> +<P> +Compiling a regular expression causes memory to be allocated and associated +with the <i>preg</i> structure. The function <b>regfree()</b> frees all such +memory, after which <i>preg</i> may no longer be used as a compiled expression. +</P> +<br><a name="SEC8" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC9" href="#TOC1">REVISION</a><br> +<P> +Last updated: 09 January 2012 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcreprecompile.html b/doc/html/pcreprecompile.html new file mode 100644 index 0000000..decb1d6 --- /dev/null +++ b/doc/html/pcreprecompile.html @@ -0,0 +1,163 @@ +<html> +<head> +<title>pcreprecompile specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcreprecompile man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SAVING AND RE-USING PRECOMPILED PCRE PATTERNS</a> +<li><a name="TOC2" href="#SEC2">SAVING A COMPILED PATTERN</a> +<li><a name="TOC3" href="#SEC3">RE-USING A PRECOMPILED PATTERN</a> +<li><a name="TOC4" href="#SEC4">COMPATIBILITY WITH DIFFERENT PCRE RELEASES</a> +<li><a name="TOC5" href="#SEC5">AUTHOR</a> +<li><a name="TOC6" href="#SEC6">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SAVING AND RE-USING PRECOMPILED PCRE PATTERNS</a><br> +<P> +If you are running an application that uses a large number of regular +expression patterns, it may be useful to store them in a precompiled form +instead of having to compile them every time the application is run. +If you are not using any private character tables (see the +<a href="pcre_maketables.html"><b>pcre_maketables()</b></a> +documentation), this is relatively straightforward. If you are using private +tables, it is a little bit more complicated. However, if you are using the +just-in-time optimization feature, it is not possible to save and reload the +JIT data. +</P> +<P> +If you save compiled patterns to a file, you can copy them to a different host +and run them there. If the two hosts have different endianness (byte order), +you should run the <b>pcre[16|32]_pattern_to_host_byte_order()</b> function on the +new host before trying to match the pattern. The matching functions return +PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness. +</P> +<P> +Compiling regular expressions with one version of PCRE for use with a different +version is not guaranteed to work and may cause crashes, and saving and +restoring a compiled pattern loses any JIT optimization data. +</P> +<br><a name="SEC2" href="#TOC1">SAVING A COMPILED PATTERN</a><br> +<P> +The value returned by <b>pcre[16|32]_compile()</b> points to a single block of +memory that holds the compiled pattern and associated data. You can find the +length of this block in bytes by calling <b>pcre[16|32]_fullinfo()</b> with an +argument of PCRE_INFO_SIZE. You can then save the data in any appropriate +manner. Here is sample code for the 8-bit library that compiles a pattern and +writes it to a file. It assumes that the variable <i>fd</i> refers to a file +that is open for output: +<pre> + int erroroffset, rc, size; + char *error; + pcre *re; + + re = pcre_compile("my pattern", 0, &error, &erroroffset, NULL); + if (re == NULL) { ... handle errors ... } + rc = pcre_fullinfo(re, NULL, PCRE_INFO_SIZE, &size); + if (rc < 0) { ... handle errors ... } + rc = fwrite(re, 1, size, fd); + if (rc != size) { ... handle errors ... } +</pre> +In this example, the bytes that comprise the compiled pattern are copied +exactly. Note that this is binary data that may contain any of the 256 possible +byte values. On systems that make a distinction between binary and non-binary +data, be sure that the file is opened for binary output. +</P> +<P> +If you want to write more than one pattern to a file, you will have to devise a +way of separating them. For binary data, preceding each pattern with its length +is probably the most straightforward approach. Another possibility is to write +out the data in hexadecimal instead of binary, one pattern to a line. +</P> +<P> +Saving compiled patterns in a file is only one possible way of storing them for +later use. They could equally well be saved in a database, or in the memory of +some daemon process that passes them via sockets to the processes that want +them. +</P> +<P> +If the pattern has been studied, it is also possible to save the normal study +data in a similar way to the compiled pattern itself. However, if the +PCRE_STUDY_JIT_COMPILE was used, the just-in-time data that is created cannot +be saved because it is too dependent on the current environment. When studying +generates additional information, <b>pcre[16|32]_study()</b> returns a pointer to a +<b>pcre[16|32]_extra</b> data block. Its format is defined in the +<a href="pcreapi.html#extradata">section on matching a pattern</a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. The <i>study_data</i> field points to the binary study data, and +this is what you must save (not the <b>pcre[16|32]_extra</b> block itself). The +length of the study data can be obtained by calling <b>pcre[16|32]_fullinfo()</b> +with an argument of PCRE_INFO_STUDYSIZE. Remember to check that +<b>pcre[16|32]_study()</b> did return a non-NULL value before trying to save the +study data. +</P> +<br><a name="SEC3" href="#TOC1">RE-USING A PRECOMPILED PATTERN</a><br> +<P> +Re-using a precompiled pattern is straightforward. Having reloaded it into main +memory, called <b>pcre[16|32]_pattern_to_host_byte_order()</b> if necessary, you +pass its pointer to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> in +the usual way. +</P> +<P> +However, if you passed a pointer to custom character tables when the pattern +was compiled (the <i>tableptr</i> argument of <b>pcre[16|32]_compile()</b>), you +must now pass a similar pointer to <b>pcre[16|32]_exec()</b> or +<b>pcre[16|32]_dfa_exec()</b>, because the value saved with the compiled pattern +will obviously be nonsense. A field in a <b>pcre[16|32]_extra()</b> block is used +to pass this data, as described in the +<a href="pcreapi.html#extradata">section on matching a pattern</a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<P> +<b>Warning:</b> The tables that <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b> use +must be the same as those that were used when the pattern was compiled. If this +is not the case, the behaviour is undefined. +</P> +<P> +If you did not provide custom character tables when the pattern was compiled, +the pointer in the compiled pattern is NULL, which causes the matching +functions to use PCRE's internal tables. Thus, you do not need to take any +special action at run time in this case. +</P> +<P> +If you saved study data with the compiled pattern, you need to create your own +<b>pcre[16|32]_extra</b> data block and set the <i>study_data</i> field to point +to the reloaded study data. You must also set the PCRE_EXTRA_STUDY_DATA bit in +the <i>flags</i> field to indicate that study data is present. Then pass the +<b>pcre[16|32]_extra</b> block to the matching function in the usual way. If the +pattern was studied for just-in-time optimization, that data cannot be saved, +and so is lost by a save/restore cycle. +</P> +<br><a name="SEC4" href="#TOC1">COMPATIBILITY WITH DIFFERENT PCRE RELEASES</a><br> +<P> +In general, it is safest to recompile all saved patterns when you update to a +new PCRE release, though not all updates actually require this. +</P> +<br><a name="SEC5" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC6" href="#TOC1">REVISION</a><br> +<P> +Last updated: 12 November 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcresample.html b/doc/html/pcresample.html new file mode 100644 index 0000000..aca9184 --- /dev/null +++ b/doc/html/pcresample.html @@ -0,0 +1,110 @@ +<html> +<head> +<title>pcresample specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcresample man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +PCRE SAMPLE PROGRAM +</b><br> +<P> +A simple, complete demonstration program, to get you started with using PCRE, +is supplied in the file <i>pcredemo.c</i> in the PCRE distribution. A listing of +this program is given in the +<a href="pcredemo.html"><b>pcredemo</b></a> +documentation. If you do not have a copy of the PCRE distribution, you can save +this listing to re-create <i>pcredemo.c</i>. +</P> +<P> +The demonstration program, which uses the original PCRE 8-bit library, compiles +the regular expression that is its first argument, and matches it against the +subject string in its second argument. No PCRE options are set, and default +character tables are used. If matching succeeds, the program outputs the +portion of the subject that matched, together with the contents of any captured +substrings. +</P> +<P> +If the -g option is given on the command line, the program then goes on to +check for further matches of the same regular expression in the same subject +string. The logic is a little bit tricky because of the possibility of matching +an empty string. Comments in the code explain what is going on. +</P> +<P> +If PCRE is installed in the standard include and library directories for your +operating system, you should be able to compile the demonstration program using +this command: +<pre> + gcc -o pcredemo pcredemo.c -lpcre +</pre> +If PCRE is installed elsewhere, you may need to add additional options to the +command line. For example, on a Unix-like system that has PCRE installed in +<i>/usr/local</i>, you can compile the demonstration program using a command +like this: +<pre> + gcc -o pcredemo -I/usr/local/include pcredemo.c -L/usr/local/lib -lpcre +</pre> +In a Windows environment, if you want to statically link the program against a +non-dll <b>pcre.a</b> file, you must uncomment the line that defines PCRE_STATIC +before including <b>pcre.h</b>, because otherwise the <b>pcre_malloc()</b> and +<b>pcre_free()</b> exported functions will be declared +<b>__declspec(dllimport)</b>, with unwanted results. +</P> +<P> +Once you have compiled and linked the demonstration program, you can run simple +tests like this: +<pre> + ./pcredemo 'cat|dog' 'the cat sat on the mat' + ./pcredemo -g 'cat|dog' 'the dog sat on the cat' +</pre> +Note that there is a much more comprehensive test program, called +<a href="pcretest.html"><b>pcretest</b>,</a> +which supports many more facilities for testing regular expressions and both +PCRE libraries. The +<a href="pcredemo.html"><b>pcredemo</b></a> +program is provided as a simple coding example. +</P> +<P> +If you try to run +<a href="pcredemo.html"><b>pcredemo</b></a> +when PCRE is not installed in the standard library directory, you may get an +error like this on some operating systems (e.g. Solaris): +<pre> + ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory +</pre> +This is caused by the way shared library support works on those systems. You +need to add +<pre> + -R/usr/local/lib +</pre> +(for example) to the compile command to get round this problem. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 10 January 2012 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcrestack.html b/doc/html/pcrestack.html new file mode 100644 index 0000000..af6406d --- /dev/null +++ b/doc/html/pcrestack.html @@ -0,0 +1,225 @@ +<html> +<head> +<title>pcrestack specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcrestack man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +PCRE DISCUSSION OF STACK USAGE +</b><br> +<P> +When you call <b>pcre[16|32]_exec()</b>, it makes use of an internal function +called <b>match()</b>. This calls itself recursively at branch points in the +pattern, in order to remember the state of the match so that it can back up and +try a different alternative if the first one fails. As matching proceeds deeper +and deeper into the tree of possibilities, the recursion depth increases. The +<b>match()</b> function is also called in other circumstances, for example, +whenever a parenthesized sub-pattern is entered, and in certain cases of +repetition. +</P> +<P> +Not all calls of <b>match()</b> increase the recursion depth; for an item such +as a* it may be called several times at the same level, after matching +different numbers of a's. Furthermore, in a number of cases where the result of +the recursive call would immediately be passed back as the result of the +current call (a "tail recursion"), the function is just restarted instead. +</P> +<P> +The above comments apply when <b>pcre[16|32]_exec()</b> is run in its normal +interpretive manner. If the pattern was studied with the +PCRE_STUDY_JIT_COMPILE option, and just-in-time compiling was successful, and +the options passed to <b>pcre[16|32]_exec()</b> were not incompatible, the matching +process uses the JIT-compiled code instead of the <b>match()</b> function. In +this case, the memory requirements are handled entirely differently. See the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation for details. +</P> +<P> +The <b>pcre[16|32]_dfa_exec()</b> function operates in an entirely different way, +and uses recursion only when there is a regular expression recursion or +subroutine call in the pattern. This includes the processing of assertion and +"once-only" subpatterns, which are handled like subroutine calls. Normally, +these are never very deep, and the limit on the complexity of +<b>pcre[16|32]_dfa_exec()</b> is controlled by the amount of workspace it is given. +However, it is possible to write patterns with runaway infinite recursions; +such patterns will cause <b>pcre[16|32]_dfa_exec()</b> to run out of stack. At +present, there is no protection against this. +</P> +<P> +The comments that follow do NOT apply to <b>pcre[16|32]_dfa_exec()</b>; they are +relevant only for <b>pcre[16|32]_exec()</b> without the JIT optimization. +</P> +<br><b> +Reducing <b>pcre[16|32]_exec()</b>'s stack usage +</b><br> +<P> +Each time that <b>match()</b> is actually called recursively, it uses memory +from the process stack. For certain kinds of pattern and data, very large +amounts of stack may be needed, despite the recognition of "tail recursion". +You can often reduce the amount of recursion, and therefore the amount of stack +used, by modifying the pattern that is being matched. Consider, for example, +this pattern: +<pre> + ([^<]|<(?!inet))+ +</pre> +It matches from wherever it starts until it encounters "<inet" or the end of +the data, and is the kind of pattern that might be used when processing an XML +file. Each iteration of the outer parentheses matches either one character that +is not "<" or a "<" that is not followed by "inet". However, each time a +parenthesis is processed, a recursion occurs, so this formulation uses a stack +frame for each matched character. For a long string, a lot of stack is +required. Consider now this rewritten pattern, which matches exactly the same +strings: +<pre> + ([^<]++|<(?!inet))+ +</pre> +This uses very much less stack, because runs of characters that do not contain +"<" are "swallowed" in one item inside the parentheses. Recursion happens only +when a "<" character that is not followed by "inet" is encountered (and we +assume this is relatively rare). A possessive quantifier is used to stop any +backtracking into the runs of non-"<" characters, but that is not related to +stack usage. +</P> +<P> +This example shows that one way of avoiding stack problems when matching long +subject strings is to write repeated parenthesized subpatterns to match more +than one character whenever possible. +</P> +<br><b> +Compiling PCRE to use heap instead of stack for <b>pcre[16|32]_exec()</b> +</b><br> +<P> +In environments where stack memory is constrained, you might want to compile +PCRE to use heap memory instead of stack for remembering back-up points when +<b>pcre[16|32]_exec()</b> is running. This makes it run a lot more slowly, however. +Details of how to do this are given in the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation. When built in this way, instead of using the stack, PCRE obtains +and frees memory by calling the functions that are pointed to by the +<b>pcre[16|32]_stack_malloc</b> and <b>pcre[16|32]_stack_free</b> variables. By +default, these point to <b>malloc()</b> and <b>free()</b>, but you can replace +the pointers to cause PCRE to use your own functions. Since the block sizes are +always the same, and are always freed in reverse order, it may be possible to +implement customized memory handlers that are more efficient than the standard +functions. +</P> +<br><b> +Limiting <b>pcre[16|32]_exec()</b>'s stack usage +</b><br> +<P> +You can set limits on the number of times that <b>match()</b> is called, both in +total and recursively. If a limit is exceeded, <b>pcre[16|32]_exec()</b> returns an +error code. Setting suitable limits should prevent it from running out of +stack. The default values of the limits are very large, and unlikely ever to +operate. They can be changed when PCRE is built, and they can also be set when +<b>pcre[16|32]_exec()</b> is called. For details of these interfaces, see the +<a href="pcrebuild.html"><b>pcrebuild</b></a> +documentation and the +<a href="pcreapi.html#extradata">section on extra data for <b>pcre[16|32]_exec()</b></a> +in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<P> +As a very rough rule of thumb, you should reckon on about 500 bytes per +recursion. Thus, if you want to limit your stack usage to 8Mb, you should set +the limit at 16000 recursions. A 64Mb stack, on the other hand, can support +around 128000 recursions. +</P> +<P> +In Unix-like environments, the <b>pcretest</b> test program has a command line +option (<b>-S</b>) that can be used to increase the size of its stack. As long +as the stack is large enough, another option (<b>-M</b>) can be used to find the +smallest limits that allow a particular pattern to match a given subject +string. This is done by calling <b>pcre[16|32]_exec()</b> repeatedly with different +limits. +</P> +<br><b> +Obtaining an estimate of stack usage +</b><br> +<P> +The actual amount of stack used per recursion can vary quite a lot, depending +on the compiler that was used to build PCRE and the optimization or debugging +options that were set for it. The rule of thumb value of 500 bytes mentioned +above may be larger or smaller than what is actually needed. A better +approximation can be obtained by running this command: +<pre> + pcretest -m -C +</pre> +The <b>-C</b> option causes <b>pcretest</b> to output information about the +options with which PCRE was compiled. When <b>-m</b> is also given (before +<b>-C</b>), information about stack use is given in a line like this: +<pre> + Match recursion uses stack: approximate frame size = 640 bytes +</pre> +The value is approximate because some recursions need a bit more (up to perhaps +16 more bytes). +</P> +<P> +If the above command is given when PCRE is compiled to use the heap instead of +the stack for recursion, the value that is output is the size of each block +that is obtained from the heap. +</P> +<br><b> +Changing stack size in Unix-like systems +</b><br> +<P> +In Unix-like environments, there is not often a problem with the stack unless +very long strings are involved, though the default limit on stack size varies +from system to system. Values from 8Mb to 64Mb are common. You can find your +default limit by running the command: +<pre> + ulimit -s +</pre> +Unfortunately, the effect of running out of stack is often SIGSEGV, though +sometimes a more explicit error message is given. You can normally increase the +limit on stack size by code such as this: +<pre> + struct rlimit rlim; + getrlimit(RLIMIT_STACK, &rlim); + rlim.rlim_cur = 100*1024*1024; + setrlimit(RLIMIT_STACK, &rlim); +</pre> +This reads the current limits (soft and hard) using <b>getrlimit()</b>, then +attempts to increase the soft limit to 100Mb using <b>setrlimit()</b>. You must +do this before calling <b>pcre[16|32]_exec()</b>. +</P> +<br><b> +Changing stack size in Mac OS X +</b><br> +<P> +Using <b>setrlimit()</b>, as described above, should also work on Mac OS X. It +is also possible to set a stack size when linking a program. There is a +discussion about stack sizes in Mac OS X at this web site: +<a href="http://developer.apple.com/qa/qa2005/qa1419.html">http://developer.apple.com/qa/qa2005/qa1419.html.</a> +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 24 June 2012 +<br> +Copyright © 1997-2012 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcresyntax.html b/doc/html/pcresyntax.html new file mode 100644 index 0000000..89f3573 --- /dev/null +++ b/doc/html/pcresyntax.html @@ -0,0 +1,538 @@ +<html> +<head> +<title>pcresyntax specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcresyntax man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a> +<li><a name="TOC2" href="#SEC2">QUOTING</a> +<li><a name="TOC3" href="#SEC3">CHARACTERS</a> +<li><a name="TOC4" href="#SEC4">CHARACTER TYPES</a> +<li><a name="TOC5" href="#SEC5">GENERAL CATEGORY PROPERTIES FOR \p and \P</a> +<li><a name="TOC6" href="#SEC6">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a> +<li><a name="TOC7" href="#SEC7">SCRIPT NAMES FOR \p AND \P</a> +<li><a name="TOC8" href="#SEC8">CHARACTER CLASSES</a> +<li><a name="TOC9" href="#SEC9">QUANTIFIERS</a> +<li><a name="TOC10" href="#SEC10">ANCHORS AND SIMPLE ASSERTIONS</a> +<li><a name="TOC11" href="#SEC11">MATCH POINT RESET</a> +<li><a name="TOC12" href="#SEC12">ALTERNATION</a> +<li><a name="TOC13" href="#SEC13">CAPTURING</a> +<li><a name="TOC14" href="#SEC14">ATOMIC GROUPS</a> +<li><a name="TOC15" href="#SEC15">COMMENT</a> +<li><a name="TOC16" href="#SEC16">OPTION SETTING</a> +<li><a name="TOC17" href="#SEC17">NEWLINE CONVENTION</a> +<li><a name="TOC18" href="#SEC18">WHAT \R MATCHES</a> +<li><a name="TOC19" href="#SEC19">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a> +<li><a name="TOC20" href="#SEC20">BACKREFERENCES</a> +<li><a name="TOC21" href="#SEC21">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a> +<li><a name="TOC22" href="#SEC22">CONDITIONAL PATTERNS</a> +<li><a name="TOC23" href="#SEC23">BACKTRACKING CONTROL</a> +<li><a name="TOC24" href="#SEC24">CALLOUTS</a> +<li><a name="TOC25" href="#SEC25">SEE ALSO</a> +<li><a name="TOC26" href="#SEC26">AUTHOR</a> +<li><a name="TOC27" href="#SEC27">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a><br> +<P> +The full syntax and semantics of the regular expressions that are supported by +PCRE are described in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. This document contains a quick-reference summary of the syntax. +</P> +<br><a name="SEC2" href="#TOC1">QUOTING</a><br> +<P> +<pre> + \x where x is non-alphanumeric is a literal x + \Q...\E treat enclosed characters as literal +</PRE> +</P> +<br><a name="SEC3" href="#TOC1">CHARACTERS</a><br> +<P> +<pre> + \a alarm, that is, the BEL character (hex 07) + \cx "control-x", where x is any ASCII character + \e escape (hex 1B) + \f form feed (hex 0C) + \n newline (hex 0A) + \r carriage return (hex 0D) + \t tab (hex 09) + \0dd character with octal code 0dd + \ddd character with octal code ddd, or backreference + \o{ddd..} character with octal code ddd.. + \xhh character with hex code hh + \x{hhh..} character with hex code hhh.. +</pre> +Note that \0dd is always an octal code, and that \8 and \9 are the literal +characters "8" and "9". +</P> +<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br> +<P> +<pre> + . any character except newline; + in dotall mode, any character whatsoever + \C one data unit, even in UTF mode (best avoided) + \d a decimal digit + \D a character that is not a decimal digit + \h a horizontal white space character + \H a character that is not a horizontal white space character + \N a character that is not a newline + \p{<i>xx</i>} a character with the <i>xx</i> property + \P{<i>xx</i>} a character without the <i>xx</i> property + \R a newline sequence + \s a white space character + \S a character that is not a white space character + \v a vertical white space character + \V a character that is not a vertical white space character + \w a "word" character + \W a "non-word" character + \X a Unicode extended grapheme cluster +</pre> +By default, \d, \s, and \w match only ASCII characters, even in UTF-8 mode +or in the 16- bit and 32-bit libraries. However, if locale-specific matching is +happening, \s and \w may also match characters with code points in the range +128-255. If the PCRE_UCP option is set, the behaviour of these escape sequences +is changed to use Unicode properties and they match many more characters. +</P> +<br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br> +<P> +<pre> + C Other + Cc Control + Cf Format + Cn Unassigned + Co Private use + Cs Surrogate + + L Letter + Ll Lower case letter + Lm Modifier letter + Lo Other letter + Lt Title case letter + Lu Upper case letter + L& Ll, Lu, or Lt + + M Mark + Mc Spacing mark + Me Enclosing mark + Mn Non-spacing mark + + N Number + Nd Decimal number + Nl Letter number + No Other number + + P Punctuation + Pc Connector punctuation + Pd Dash punctuation + Pe Close punctuation + Pf Final punctuation + Pi Initial punctuation + Po Other punctuation + Ps Open punctuation + + S Symbol + Sc Currency symbol + Sk Modifier symbol + Sm Mathematical symbol + So Other symbol + + Z Separator + Zl Line separator + Zp Paragraph separator + Zs Space separator +</PRE> +</P> +<br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br> +<P> +<pre> + Xan Alphanumeric: union of properties L and N + Xps POSIX space: property Z or tab, NL, VT, FF, CR + Xsp Perl space: property Z or tab, NL, VT, FF, CR + Xuc Univerally-named character: one that can be + represented by a Universal Character Name + Xwd Perl word: property Xan or underscore +</pre> +Perl and POSIX space are now the same. Perl added VT to its space character set +at release 5.18 and PCRE changed at release 8.34. +</P> +<br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br> +<P> +Arabic, +Armenian, +Avestan, +Balinese, +Bamum, +Batak, +Bengali, +Bopomofo, +Brahmi, +Braille, +Buginese, +Buhid, +Canadian_Aboriginal, +Carian, +Chakma, +Cham, +Cherokee, +Common, +Coptic, +Cuneiform, +Cypriot, +Cyrillic, +Deseret, +Devanagari, +Egyptian_Hieroglyphs, +Ethiopic, +Georgian, +Glagolitic, +Gothic, +Greek, +Gujarati, +Gurmukhi, +Han, +Hangul, +Hanunoo, +Hebrew, +Hiragana, +Imperial_Aramaic, +Inherited, +Inscriptional_Pahlavi, +Inscriptional_Parthian, +Javanese, +Kaithi, +Kannada, +Katakana, +Kayah_Li, +Kharoshthi, +Khmer, +Lao, +Latin, +Lepcha, +Limbu, +Linear_B, +Lisu, +Lycian, +Lydian, +Malayalam, +Mandaic, +Meetei_Mayek, +Meroitic_Cursive, +Meroitic_Hieroglyphs, +Miao, +Mongolian, +Myanmar, +New_Tai_Lue, +Nko, +Ogham, +Old_Italic, +Old_Persian, +Old_South_Arabian, +Old_Turkic, +Ol_Chiki, +Oriya, +Osmanya, +Phags_Pa, +Phoenician, +Rejang, +Runic, +Samaritan, +Saurashtra, +Sharada, +Shavian, +Sinhala, +Sora_Sompeng, +Sundanese, +Syloti_Nagri, +Syriac, +Tagalog, +Tagbanwa, +Tai_Le, +Tai_Tham, +Tai_Viet, +Takri, +Tamil, +Telugu, +Thaana, +Thai, +Tibetan, +Tifinagh, +Ugaritic, +Vai, +Yi. +</P> +<br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br> +<P> +<pre> + [...] positive character class + [^...] negative character class + [x-y] range (can be used for hex characters) + [[:xxx:]] positive POSIX named set + [[:^xxx:]] negative POSIX named set + + alnum alphanumeric + alpha alphabetic + ascii 0-127 + blank space or tab + cntrl control character + digit decimal digit + graph printing, excluding space + lower lower case letter + print printing, including space + punct printing, excluding alphanumeric + space white space + upper upper case letter + word same as \w + xdigit hexadecimal digit +</pre> +In PCRE, POSIX character set names recognize only ASCII characters by default, +but some of them use Unicode properties if PCRE_UCP is set. You can use +\Q...\E inside a character class. +</P> +<br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br> +<P> +<pre> + ? 0 or 1, greedy + ?+ 0 or 1, possessive + ?? 0 or 1, lazy + * 0 or more, greedy + *+ 0 or more, possessive + *? 0 or more, lazy + + 1 or more, greedy + ++ 1 or more, possessive + +? 1 or more, lazy + {n} exactly n + {n,m} at least n, no more than m, greedy + {n,m}+ at least n, no more than m, possessive + {n,m}? at least n, no more than m, lazy + {n,} n or more, greedy + {n,}+ n or more, possessive + {n,}? n or more, lazy +</PRE> +</P> +<br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br> +<P> +<pre> + \b word boundary + \B not a word boundary + ^ start of subject + also after internal newline in multiline mode + \A start of subject + $ end of subject + also before newline at end of subject + also before internal newline in multiline mode + \Z end of subject + also before newline at end of subject + \z end of subject + \G first matching position in subject +</PRE> +</P> +<br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br> +<P> +<pre> + \K reset start of match +</pre> +\K is honoured in positive assertions, but ignored in negative ones. +</P> +<br><a name="SEC12" href="#TOC1">ALTERNATION</a><br> +<P> +<pre> + expr|expr|expr... +</PRE> +</P> +<br><a name="SEC13" href="#TOC1">CAPTURING</a><br> +<P> +<pre> + (...) capturing group + (?<name>...) named capturing group (Perl) + (?'name'...) named capturing group (Perl) + (?P<name>...) named capturing group (Python) + (?:...) non-capturing group + (?|...) non-capturing group; reset group numbers for + capturing groups in each alternative +</PRE> +</P> +<br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br> +<P> +<pre> + (?>...) atomic, non-capturing group +</PRE> +</P> +<br><a name="SEC15" href="#TOC1">COMMENT</a><br> +<P> +<pre> + (?#....) comment (not nestable) +</PRE> +</P> +<br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br> +<P> +<pre> + (?i) caseless + (?J) allow duplicate names + (?m) multiline + (?s) single line (dotall) + (?U) default ungreedy (lazy) + (?x) extended (ignore white space) + (?-...) unset option(s) +</pre> +The following are recognized only at the very start of a pattern or after one +of the newline or \R options with similar syntax. More than one of them may +appear. +<pre> + (*LIMIT_MATCH=d) set the match limit to d (decimal number) + (*LIMIT_RECURSION=d) set the recursion limit to d (decimal number) + (*NO_AUTO_POSSESS) no auto-possessification (PCRE_NO_AUTO_POSSESS) + (*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE) + (*UTF8) set UTF-8 mode: 8-bit library (PCRE_UTF8) + (*UTF16) set UTF-16 mode: 16-bit library (PCRE_UTF16) + (*UTF32) set UTF-32 mode: 32-bit library (PCRE_UTF32) + (*UTF) set appropriate UTF mode for the library in use + (*UCP) set PCRE_UCP (use Unicode properties for \d etc) +</pre> +Note that LIMIT_MATCH and LIMIT_RECURSION can only reduce the value of the +limits set by the caller of pcre_exec(), not increase them. +</P> +<br><a name="SEC17" href="#TOC1">NEWLINE CONVENTION</a><br> +<P> +These are recognized only at the very start of the pattern or after option +settings with a similar syntax. +<pre> + (*CR) carriage return only + (*LF) linefeed only + (*CRLF) carriage return followed by linefeed + (*ANYCRLF) all three of the above + (*ANY) any Unicode newline sequence +</PRE> +</P> +<br><a name="SEC18" href="#TOC1">WHAT \R MATCHES</a><br> +<P> +These are recognized only at the very start of the pattern or after option +setting with a similar syntax. +<pre> + (*BSR_ANYCRLF) CR, LF, or CRLF + (*BSR_UNICODE) any Unicode newline sequence +</PRE> +</P> +<br><a name="SEC19" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br> +<P> +<pre> + (?=...) positive look ahead + (?!...) negative look ahead + (?<=...) positive look behind + (?<!...) negative look behind +</pre> +Each top-level branch of a look behind must be of a fixed length. +</P> +<br><a name="SEC20" href="#TOC1">BACKREFERENCES</a><br> +<P> +<pre> + \n reference by number (can be ambiguous) + \gn reference by number + \g{n} reference by number + \g{-n} relative reference by number + \k<name> reference by name (Perl) + \k'name' reference by name (Perl) + \g{name} reference by name (Perl) + \k{name} reference by name (.NET) + (?P=name) reference by name (Python) +</PRE> +</P> +<br><a name="SEC21" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br> +<P> +<pre> + (?R) recurse whole pattern + (?n) call subpattern by absolute number + (?+n) call subpattern by relative number + (?-n) call subpattern by relative number + (?&name) call subpattern by name (Perl) + (?P>name) call subpattern by name (Python) + \g<name> call subpattern by name (Oniguruma) + \g'name' call subpattern by name (Oniguruma) + \g<n> call subpattern by absolute number (Oniguruma) + \g'n' call subpattern by absolute number (Oniguruma) + \g<+n> call subpattern by relative number (PCRE extension) + \g'+n' call subpattern by relative number (PCRE extension) + \g<-n> call subpattern by relative number (PCRE extension) + \g'-n' call subpattern by relative number (PCRE extension) +</PRE> +</P> +<br><a name="SEC22" href="#TOC1">CONDITIONAL PATTERNS</a><br> +<P> +<pre> + (?(condition)yes-pattern) + (?(condition)yes-pattern|no-pattern) + + (?(n)... absolute reference condition + (?(+n)... relative reference condition + (?(-n)... relative reference condition + (?(<name>)... named reference condition (Perl) + (?('name')... named reference condition (Perl) + (?(name)... named reference condition (PCRE) + (?(R)... overall recursion condition + (?(Rn)... specific group recursion condition + (?(R&name)... specific recursion condition + (?(DEFINE)... define subpattern for reference + (?(assert)... assertion condition +</PRE> +</P> +<br><a name="SEC23" href="#TOC1">BACKTRACKING CONTROL</a><br> +<P> +The following act immediately they are reached: +<pre> + (*ACCEPT) force successful match + (*FAIL) force backtrack; synonym (*F) + (*MARK:NAME) set name to be passed back; synonym (*:NAME) +</pre> +The following act only when a subsequent match failure causes a backtrack to +reach them. They all force a match failure, but they differ in what happens +afterwards. Those that advance the start-of-match point do so only if the +pattern is not anchored. +<pre> + (*COMMIT) overall failure, no advance of starting point + (*PRUNE) advance to next starting character + (*PRUNE:NAME) equivalent to (*MARK:NAME)(*PRUNE) + (*SKIP) advance to current matching position + (*SKIP:NAME) advance to position corresponding to an earlier + (*MARK:NAME); if not found, the (*SKIP) is ignored + (*THEN) local failure, backtrack to next alternation + (*THEN:NAME) equivalent to (*MARK:NAME)(*THEN) +</PRE> +</P> +<br><a name="SEC24" href="#TOC1">CALLOUTS</a><br> +<P> +<pre> + (?C) callout + (?Cn) callout with data n +</PRE> +</P> +<br><a name="SEC25" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), +<b>pcrematching</b>(3), <b>pcre</b>(3). +</P> +<br><a name="SEC26" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC27" href="#TOC1">REVISION</a><br> +<P> +Last updated: 08 January 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcretest.html b/doc/html/pcretest.html new file mode 100644 index 0000000..839fabf --- /dev/null +++ b/doc/html/pcretest.html @@ -0,0 +1,1158 @@ +<html> +<head> +<title>pcretest specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcretest man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<ul> +<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> +<li><a name="TOC2" href="#SEC2">INPUT DATA FORMAT</a> +<li><a name="TOC3" href="#SEC3">PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a> +<li><a name="TOC4" href="#SEC4">COMMAND LINE OPTIONS</a> +<li><a name="TOC5" href="#SEC5">DESCRIPTION</a> +<li><a name="TOC6" href="#SEC6">PATTERN MODIFIERS</a> +<li><a name="TOC7" href="#SEC7">DATA LINES</a> +<li><a name="TOC8" href="#SEC8">THE ALTERNATIVE MATCHING FUNCTION</a> +<li><a name="TOC9" href="#SEC9">DEFAULT OUTPUT FROM PCRETEST</a> +<li><a name="TOC10" href="#SEC10">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a> +<li><a name="TOC11" href="#SEC11">RESTARTING AFTER A PARTIAL MATCH</a> +<li><a name="TOC12" href="#SEC12">CALLOUTS</a> +<li><a name="TOC13" href="#SEC13">NON-PRINTING CHARACTERS</a> +<li><a name="TOC14" href="#SEC14">SAVING AND RELOADING COMPILED PATTERNS</a> +<li><a name="TOC15" href="#SEC15">SEE ALSO</a> +<li><a name="TOC16" href="#SEC16">AUTHOR</a> +<li><a name="TOC17" href="#SEC17">REVISION</a> +</ul> +<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> +<P> +<b>pcretest [options] [input file [output file]]</b> +<br> +<br> +<b>pcretest</b> was written as a test program for the PCRE regular expression +library itself, but it can also be used for experimenting with regular +expressions. This document describes the features of the test program; for +details of the regular expressions themselves, see the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. For details of the PCRE library function calls and their +options, see the +<a href="pcreapi.html"><b>pcreapi</b></a> +, +<a href="pcre16.html"><b>pcre16</b></a> +and +<a href="pcre32.html"><b>pcre32</b></a> +documentation. +</P> +<P> +The input for <b>pcretest</b> is a sequence of regular expression patterns and +strings to be matched, as described below. The output shows the result of each +match. Options on the command line and the patterns control PCRE options and +exactly what is output. +</P> +<P> +As PCRE has evolved, it has acquired many different features, and as a result, +<b>pcretest</b> now has rather a lot of obscure options for testing every +possible feature. Some of these options are specifically designed for use in +conjunction with the test script and data files that are distributed as part of +PCRE, and are unlikely to be of use otherwise. They are all documented here, +but without much justification. +</P> +<br><a name="SEC2" href="#TOC1">INPUT DATA FORMAT</a><br> +<P> +Input to <b>pcretest</b> is processed line by line, either by calling the C +library's <b>fgets()</b> function, or via the <b>libreadline</b> library (see +below). In Unix-like environments, <b>fgets()</b> treats any bytes other than +newline as data characters. However, in some Windows environments character 26 +(hex 1A) causes an immediate end of file, and no further data is read. For +maximum portability, therefore, it is safest to use only ASCII characters in +<b>pcretest</b> input files. +</P> +<br><a name="SEC3" href="#TOC1">PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a><br> +<P> +From release 8.30, two separate PCRE libraries can be built. The original one +supports 8-bit character strings, whereas the newer 16-bit library supports +character strings encoded in 16-bit units. From release 8.32, a third library +can be built, supporting character strings encoded in 32-bit units. The +<b>pcretest</b> program can be used to test all three libraries. However, it is +itself still an 8-bit program, reading 8-bit input and writing 8-bit output. +When testing the 16-bit or 32-bit library, the patterns and data strings are +converted to 16- or 32-bit format before being passed to the PCRE library +functions. Results are converted to 8-bit for output. +</P> +<P> +References to functions and structures of the form <b>pcre[16|32]_xx</b> below +mean "<b>pcre_xx</b> when using the 8-bit library, <b>pcre16_xx</b> when using +the 16-bit library, or <b>pcre32_xx</b> when using the 32-bit library". +</P> +<br><a name="SEC4" href="#TOC1">COMMAND LINE OPTIONS</a><br> +<P> +<b>-8</b> +If both the 8-bit library has been built, this option causes the 8-bit library +to be used (which is the default); if the 8-bit library has not been built, +this option causes an error. +</P> +<P> +<b>-16</b> +If both the 8-bit or the 32-bit, and the 16-bit libraries have been built, this +option causes the 16-bit library to be used. If only the 16-bit library has been +built, this is the default (so has no effect). If only the 8-bit or the 32-bit +library has been built, this option causes an error. +</P> +<P> +<b>-32</b> +If both the 8-bit or the 16-bit, and the 32-bit libraries have been built, this +option causes the 32-bit library to be used. If only the 32-bit library has been +built, this is the default (so has no effect). If only the 8-bit or the 16-bit +library has been built, this option causes an error. +</P> +<P> +<b>-b</b> +Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the +internal form is output after compilation. +</P> +<P> +<b>-C</b> +Output the version number of the PCRE library, and all available information +about the optional features that are included, and then exit with zero exit +code. All other options are ignored. +</P> +<P> +<b>-C</b> <i>option</i> +Output information about a specific build-time option, then exit. This +functionality is intended for use in scripts such as <b>RunTest</b>. The +following options output the value and set the exit code as indicated: +<pre> + ebcdic-nl the code for LF (= NL) in an EBCDIC environment: + 0x15 or 0x25 + 0 if used in an ASCII environment + exit code is always 0 + linksize the configured internal link size (2, 3, or 4) + exit code is set to the link size + newline the default newline setting: + CR, LF, CRLF, ANYCRLF, or ANY + exit code is always 0 + bsr the default setting for what \R matches: + ANYCRLF or ANY + exit code is always 0 +</pre> +The following options output 1 for true or 0 for false, and set the exit code +to the same value: +<pre> + ebcdic compiled for an EBCDIC environment + jit just-in-time support is available + pcre16 the 16-bit library was built + pcre32 the 32-bit library was built + pcre8 the 8-bit library was built + ucp Unicode property support is available + utf UTF-8 and/or UTF-16 and/or UTF-32 support + is available +</pre> +If an unknown option is given, an error message is output; the exit code is 0. +</P> +<P> +<b>-d</b> +Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal +form and information about the compiled pattern is output after compilation; +<b>-d</b> is equivalent to <b>-b -i</b>. +</P> +<P> +<b>-dfa</b> +Behave as if each data line contains the \D escape sequence; this causes the +alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, to be used instead +of the standard <b>pcre[16|32]_exec()</b> function (more detail is given below). +</P> +<P> +<b>-help</b> +Output a brief summary these options and then exit. +</P> +<P> +<b>-i</b> +Behave as if each pattern has the <b>/I</b> modifier; information about the +compiled pattern is given after compilation. +</P> +<P> +<b>-M</b> +Behave as if each data line contains the \M escape sequence; this causes +PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by +calling <b>pcre[16|32]_exec()</b> repeatedly with different limits. +</P> +<P> +<b>-m</b> +Output the size of each compiled pattern after it has been compiled. This is +equivalent to adding <b>/M</b> to each regular expression. The size is given in +bytes for both libraries. +</P> +<P> +<b>-O</b> +Behave as if each pattern has the <b>/O</b> modifier, that is disable +auto-possessification for all patterns. +</P> +<P> +<b>-o</b> <i>osize</i> +Set the number of elements in the output vector that is used when calling +<b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> to be <i>osize</i>. The +default value is 45, which is enough for 14 capturing subexpressions for +<b>pcre[16|32]_exec()</b> or 22 different matches for +<b>pcre[16|32]_dfa_exec()</b>. +The vector size can be changed for individual matching calls by including \O +in the data line (see below). +</P> +<P> +<b>-p</b> +Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is +used to call PCRE. None of the other options has any effect when <b>-p</b> is +set. This option can be used only with the 8-bit library. +</P> +<P> +<b>-q</b> +Do not output the version number of <b>pcretest</b> at the start of execution. +</P> +<P> +<b>-S</b> <i>size</i> +On Unix-like systems, set the size of the run-time stack to <i>size</i> +megabytes. +</P> +<P> +<b>-s</b> or <b>-s+</b> +Behave as if each pattern has the <b>/S</b> modifier; in other words, force each +pattern to be studied. If <b>-s+</b> is used, all the JIT compile options are +passed to <b>pcre[16|32]_study()</b>, causing just-in-time optimization to be set +up if it is available, for both full and partial matching. Specific JIT compile +options can be selected by following <b>-s+</b> with a digit in the range 1 to +7, which selects the JIT compile modes as follows: +<pre> + 1 normal match only + 2 soft partial match only + 3 normal match and soft partial match + 4 hard partial match only + 6 soft and hard partial match + 7 all three modes (default) +</pre> +If <b>-s++</b> is used instead of <b>-s+</b> (with or without a following digit), +the text "(JIT)" is added to the first output line after a match or no match +when JIT-compiled code was actually used. +<br> +<br> +Note that there are pattern options that can override <b>-s</b>, either +specifying no studying at all, or suppressing JIT compilation. +<br> +<br> +If the <b>/I</b> or <b>/D</b> option is present on a pattern (requesting output +about the compiled pattern), information about the result of studying is not +included when studying is caused only by <b>-s</b> and neither <b>-i</b> nor +<b>-d</b> is present on the command line. This behaviour means that the output +from tests that are run with and without <b>-s</b> should be identical, except +when options that output information about the actual running of a match are +set. +<br> +<br> +The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give information about +resources used, are likely to produce different output with and without +<b>-s</b>. Output may also differ if the <b>/C</b> option is present on an +individual pattern. This uses callouts to trace the the matching process, and +this may be different between studied and non-studied patterns. If the pattern +contains (*MARK) items there may also be differences, for the same reason. The +<b>-s</b> command line option can be overridden for specific patterns that +should never be studied (see the <b>/S</b> pattern modifier below). +</P> +<P> +<b>-t</b> +Run each compile, study, and match many times with a timer, and output the +resulting times per compile, study, or match (in milliseconds). Do not set +<b>-m</b> with <b>-t</b>, because you will then get the size output a zillion +times, and the timing will be distorted. You can control the number of +iterations that are used for timing by following <b>-t</b> with a number (as a +separate item on the command line). For example, "-t 1000" iterates 1000 times. +The default is to iterate 500000 times. +</P> +<P> +<b>-tm</b> +This is like <b>-t</b> except that it times only the matching phase, not the +compile or study phases. +</P> +<P> +<b>-T</b> <b>-TM</b> +These behave like <b>-t</b> and <b>-tm</b>, but in addition, at the end of a run, +the total times for all compiles, studies, and matches are output. +</P> +<br><a name="SEC5" href="#TOC1">DESCRIPTION</a><br> +<P> +If <b>pcretest</b> is given two filename arguments, it reads from the first and +writes to the second. If it is given only one filename argument, it reads from +that file and writes to stdout. Otherwise, it reads from stdin and writes to +stdout, and prompts for each line of input, using "re>" to prompt for regular +expressions, and "data>" to prompt for data lines. +</P> +<P> +When <b>pcretest</b> is built, a configuration option can specify that it should +be linked with the <b>libreadline</b> library. When this is done, if the input +is from a terminal, it is read using the <b>readline()</b> function. This +provides line-editing and history facilities. The output from the <b>-help</b> +option states whether or not <b>readline()</b> will be used. +</P> +<P> +The program handles any number of sets of input on a single input file. Each +set starts with a regular expression, and continues with any number of data +lines to be matched against that pattern. +</P> +<P> +Each data line is matched separately and independently. If you want to do +multi-line matches, you have to use the \n escape sequence (or \r or \r\n, +etc., depending on the newline setting) in a single line of input to encode the +newline sequences. There is no limit on the length of data lines; the input +buffer is automatically extended if it is too small. +</P> +<P> +An empty line signals the end of the data lines, at which point a new regular +expression is read. The regular expressions are given enclosed in any +non-alphanumeric delimiters other than backslash, for example: +<pre> + /(a|bc)x+yz/ +</pre> +White space before the initial delimiter is ignored. A regular expression may +be continued over several input lines, in which case the newline characters are +included within it. It is possible to include the delimiter within the pattern +by escaping it, for example +<pre> + /abc\/def/ +</pre> +If you do so, the escape and the delimiter form part of the pattern, but since +delimiters are always non-alphanumeric, this does not affect its interpretation. +If the terminating delimiter is immediately followed by a backslash, for +example, +<pre> + /abc/\ +</pre> +then a backslash is added to the end of the pattern. This is done to provide a +way of testing the error condition that arises if a pattern finishes with a +backslash, because +<pre> + /abc\/ +</pre> +is interpreted as the first line of a pattern that starts with "abc/", causing +pcretest to read the next line as a continuation of the regular expression. +</P> +<br><a name="SEC6" href="#TOC1">PATTERN MODIFIERS</a><br> +<P> +A pattern may be followed by any number of modifiers, which are mostly single +characters, though some of these can be qualified by further characters. +Following Perl usage, these are referred to below as, for example, "the +<b>/i</b> modifier", even though the delimiter of the pattern need not always be +a slash, and no slash is used when writing modifiers. White space may appear +between the final pattern delimiter and the first modifier, and between the +modifiers themselves. For reference, here is a complete list of modifiers. They +fall into several groups that are described in detail in the following +sections. +<pre> + <b>/8</b> set UTF mode + <b>/9</b> set PCRE_NEVER_UTF (locks out UTF mode) + <b>/?</b> disable UTF validity check + <b>/+</b> show remainder of subject after match + <b>/=</b> show all captures (not just those that are set) + + <b>/A</b> set PCRE_ANCHORED + <b>/B</b> show compiled code + <b>/C</b> set PCRE_AUTO_CALLOUT + <b>/D</b> same as <b>/B</b> plus <b>/I</b> + <b>/E</b> set PCRE_DOLLAR_ENDONLY + <b>/F</b> flip byte order in compiled pattern + <b>/f</b> set PCRE_FIRSTLINE + <b>/G</b> find all matches (shorten string) + <b>/g</b> find all matches (use startoffset) + <b>/I</b> show information about pattern + <b>/i</b> set PCRE_CASELESS + <b>/J</b> set PCRE_DUPNAMES + <b>/K</b> show backtracking control names + <b>/L</b> set locale + <b>/M</b> show compiled memory size + <b>/m</b> set PCRE_MULTILINE + <b>/N</b> set PCRE_NO_AUTO_CAPTURE + <b>/O</b> set PCRE_NO_AUTO_POSSESS + <b>/P</b> use the POSIX wrapper + <b>/Q</b> test external stack check function + <b>/S</b> study the pattern after compilation + <b>/s</b> set PCRE_DOTALL + <b>/T</b> select character tables + <b>/U</b> set PCRE_UNGREEDY + <b>/W</b> set PCRE_UCP + <b>/X</b> set PCRE_EXTRA + <b>/x</b> set PCRE_EXTENDED + <b>/Y</b> set PCRE_NO_START_OPTIMIZE + <b>/Z</b> don't show lengths in <b>/B</b> output + + <b>/<any></b> set PCRE_NEWLINE_ANY + <b>/<anycrlf></b> set PCRE_NEWLINE_ANYCRLF + <b>/<cr></b> set PCRE_NEWLINE_CR + <b>/<crlf></b> set PCRE_NEWLINE_CRLF + <b>/<lf></b> set PCRE_NEWLINE_LF + <b>/<bsr_anycrlf></b> set PCRE_BSR_ANYCRLF + <b>/<bsr_unicode></b> set PCRE_BSR_UNICODE + <b>/<JS></b> set PCRE_JAVASCRIPT_COMPAT + +</PRE> +</P> +<br><b> +Perl-compatible modifiers +</b><br> +<P> +The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS, +PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when +<b>pcre[16|32]_compile()</b> is called. These four modifier letters have the same +effect as they do in Perl. For example: +<pre> + /caseless/i + +</PRE> +</P> +<br><b> +Modifiers for other PCRE options +</b><br> +<P> +The following table shows additional modifiers for setting PCRE compile-time +options that do not correspond to anything in Perl: +<pre> + <b>/8</b> PCRE_UTF8 ) when using the 8-bit + <b>/?</b> PCRE_NO_UTF8_CHECK ) library + + <b>/8</b> PCRE_UTF16 ) when using the 16-bit + <b>/?</b> PCRE_NO_UTF16_CHECK ) library + + <b>/8</b> PCRE_UTF32 ) when using the 32-bit + <b>/?</b> PCRE_NO_UTF32_CHECK ) library + + <b>/9</b> PCRE_NEVER_UTF + <b>/A</b> PCRE_ANCHORED + <b>/C</b> PCRE_AUTO_CALLOUT + <b>/E</b> PCRE_DOLLAR_ENDONLY + <b>/f</b> PCRE_FIRSTLINE + <b>/J</b> PCRE_DUPNAMES + <b>/N</b> PCRE_NO_AUTO_CAPTURE + <b>/O</b> PCRE_NO_AUTO_POSSESS + <b>/U</b> PCRE_UNGREEDY + <b>/W</b> PCRE_UCP + <b>/X</b> PCRE_EXTRA + <b>/Y</b> PCRE_NO_START_OPTIMIZE + <b>/<any></b> PCRE_NEWLINE_ANY + <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF + <b>/<cr></b> PCRE_NEWLINE_CR + <b>/<crlf></b> PCRE_NEWLINE_CRLF + <b>/<lf></b> PCRE_NEWLINE_LF + <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF + <b>/<bsr_unicode></b> PCRE_BSR_UNICODE + <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT +</pre> +The modifiers that are enclosed in angle brackets are literal strings as shown, +including the angle brackets, but the letters within can be in either case. +This example sets multiline matching with CRLF as the line ending sequence: +<pre> + /^abc/m<CRLF> +</pre> +As well as turning on the PCRE_UTF8/16/32 option, the <b>/8</b> modifier causes +all non-printing characters in output strings to be printed using the +\x{hh...} notation. Otherwise, those less than 0x100 are output in hex without +the curly brackets. +</P> +<P> +Full details of the PCRE options are given in the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation. +</P> +<br><b> +Finding all matches in a string +</b><br> +<P> +Searching for all possible matches within each subject string can be requested +by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called +again to search the remainder of the subject string. The difference between +<b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to +<b>pcre[16|32]_exec()</b> to start searching at a new point within the entire +string (which is in effect what Perl does), whereas the latter passes over a +shortened substring. This makes a difference to the matching process if the +pattern begins with a lookbehind assertion (including \b or \B). +</P> +<P> +If any call to <b>pcre[16|32]_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches +an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and +PCRE_ANCHORED flags set in order to search for another, non-empty, match at the +same point. If this second match fails, the start offset is advanced, and the +normal match is retried. This imitates the way Perl handles such cases when +using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start +offset is advanced by one character, but if the newline convention recognizes +CRLF as a newline, and the current character is CR followed by LF, an advance +of two is used. +</P> +<br><b> +Other modifiers +</b><br> +<P> +There are yet more modifiers for controlling the way <b>pcretest</b> +operates. +</P> +<P> +The <b>/+</b> modifier requests that as well as outputting the substring that +matched the entire pattern, <b>pcretest</b> should in addition output the +remainder of the subject string. This is useful for tests where the subject +contains multiple copies of the same substring. If the <b>+</b> modifier appears +twice, the same action is taken for captured substrings. In each case the +remainder is output on the following line with a plus character following the +capture number. Note that this modifier must not immediately follow the /S +modifier because /S+ and /S++ have other meanings. +</P> +<P> +The <b>/=</b> modifier requests that the values of all potential captured +parentheses be output after a match. By default, only those up to the highest +one actually used in the match are output (corresponding to the return code +from <b>pcre[16|32]_exec()</b>). Values in the offsets vector corresponding to +higher numbers should be set to -1, and these are output as "<unset>". This +modifier gives a way of checking that this is happening. +</P> +<P> +The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b> +output a representation of the compiled code after compilation. Normally this +information contains length and offset values; however, if <b>/Z</b> is also +present, this data is replaced by spaces. This is a special feature for use in +the automatic test scripts; it ensures that the same output is generated for +different internal link sizes. +</P> +<P> +The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to +<b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers. +</P> +<P> +The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the +2-byte and 4-byte fields in the compiled pattern. This facility is for testing +the feature in PCRE that allows it to execute patterns that were compiled on a +host with a different endianness. This feature is not available when the POSIX +interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is +specified. See also the section about saving and reloading compiled patterns +below. +</P> +<P> +The <b>/I</b> modifier requests that <b>pcretest</b> output information about the +compiled pattern (whether it is anchored, has a fixed first character, and +so on). It does this by calling <b>pcre[16|32]_fullinfo()</b> after compiling a +pattern. If the pattern is studied, the results of that are also output. In +this output, the word "char" means a non-UTF character, that is, the value of a +single data item (8-bit, 16-bit, or 32-bit, depending on the library that is +being tested). +</P> +<P> +The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking +control verbs that are returned from calls to <b>pcre[16|32]_exec()</b>. It causes +<b>pcretest</b> to create a <b>pcre[16|32]_extra</b> block if one has not already +been created by a call to <b>pcre[16|32]_study()</b>, and to set the +PCRE_EXTRA_MARK flag and the <b>mark</b> field within it, every time that +<b>pcre[16|32]_exec()</b> is called. If the variable that the <b>mark</b> field +points to is non-NULL for a match, non-match, or partial match, <b>pcretest</b> +prints the string to which it points. For a match, this is shown on a line by +itself, tagged with "MK:". For a non-match it is added to the message. +</P> +<P> +The <b>/L</b> modifier must be followed directly by the name of a locale, for +example, +<pre> + /pattern/Lfr_FR +</pre> +For this reason, it must be the last modifier. The given locale is set, +<b>pcre[16|32]_maketables()</b> is called to build a set of character tables for +the locale, and this is then passed to <b>pcre[16|32]_compile()</b> when compiling +the regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is +passed as the tables pointer; that is, <b>/L</b> applies only to the expression +on which it appears. +</P> +<P> +The <b>/M</b> modifier causes the size in bytes of the memory block used to hold +the compiled pattern to be output. This does not include the size of the +<b>pcre[16|32]</b> block; it is just the actual compiled data. If the pattern is +successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the +JIT compiled code is also output. +</P> +<P> +The <b>/Q</b> modifier is used to test the use of <b>pcre_stack_guard</b>. It +must be followed by '0' or '1', specifying the return code to be given from an +external function that is passed to PCRE and used for stack checking during +compilation (see the +<a href="pcreapi.html"><b>pcreapi</b></a> +documentation for details). +</P> +<P> +The <b>/S</b> modifier causes <b>pcre[16|32]_study()</b> to be called after the +expression has been compiled, and the results used when the expression is +matched. There are a number of qualifying characters that may follow <b>/S</b>. +They may appear in any order. +</P> +<P> +If <b>/S</b> is followed by an exclamation mark, <b>pcre[16|32]_study()</b> is +called with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a +<b>pcre_extra</b> block, even when studying discovers no useful information. +</P> +<P> +If <b>/S</b> is followed by a second S character, it suppresses studying, even +if it was requested externally by the <b>-s</b> command line option. This makes +it possible to specify that certain patterns are always studied, and others are +never studied, independently of <b>-s</b>. This feature is used in the test +files in a few cases where the output is different when the pattern is studied. +</P> +<P> +If the <b>/S</b> modifier is followed by a + character, the call to +<b>pcre[16|32]_study()</b> is made with all the JIT study options, requesting +just-in-time optimization support if it is available, for both normal and +partial matching. If you want to restrict the JIT compiling modes, you can +follow <b>/S+</b> with a digit in the range 1 to 7: +<pre> + 1 normal match only + 2 soft partial match only + 3 normal match and soft partial match + 4 hard partial match only + 6 soft and hard partial match + 7 all three modes (default) +</pre> +If <b>/S++</b> is used instead of <b>/S+</b> (with or without a following digit), +the text "(JIT)" is added to the first output line after a match or no match +when JIT-compiled code was actually used. +</P> +<P> +Note that there is also an independent <b>/+</b> modifier; it must not be given +immediately after <b>/S</b> or <b>/S+</b> because this will be misinterpreted. +</P> +<P> +If JIT studying is successful, the compiled JIT code will automatically be used +when <b>pcre[16|32]_exec()</b> is run, except when incompatible run-time options +are specified. For more details, see the +<a href="pcrejit.html"><b>pcrejit</b></a> +documentation. See also the <b>\J</b> escape sequence below for a way of +setting the size of the JIT stack. +</P> +<P> +Finally, if <b>/S</b> is followed by a minus character, JIT compilation is +suppressed, even if it was requested externally by the <b>-s</b> command line +option. This makes it possible to specify that JIT is never to be used for +certain patterns. +</P> +<P> +The <b>/T</b> modifier must be followed by a single digit. It causes a specific +set of built-in character tables to be passed to <b>pcre[16|32]_compile()</b>. It +is used in the standard PCRE tests to check behaviour with different character +tables. The digit specifies the tables as follows: +<pre> + 0 the default ASCII tables, as distributed in + pcre_chartables.c.dist + 1 a set of tables defining ISO 8859 characters +</pre> +In table 1, some characters whose codes are greater than 128 are identified as +letters, digits, spaces, etc. +</P> +<br><b> +Using the POSIX wrapper API +</b><br> +<P> +The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper +API rather than its native API. This supports only the 8-bit library. When +<b>/P</b> is set, the following modifiers set options for the <b>regcomp()</b> +function: +<pre> + /i REG_ICASE + /m REG_NEWLINE + /N REG_NOSUB + /s REG_DOTALL ) + /U REG_UNGREEDY ) These options are not part of + /W REG_UCP ) the POSIX standard + /8 REG_UTF8 ) +</pre> +The <b>/+</b> modifier works as described above. All other modifiers are +ignored. +</P> +<br><b> +Locking out certain modifiers +</b><br> +<P> +PCRE can be compiled with or without support for certain features such as +UTF-8/16/32 or Unicode properties. Accordingly, the standard tests are split up +into a number of different files that are selected for running depending on +which features are available. When updating the tests, it is all too easy to +put a new test into the wrong file by mistake; for example, to put a test that +requires UTF support into a file that is used when it is not available. To help +detect such mistakes as early as possible, there is a facility for locking out +specific modifiers. If an input line for <b>pcretest</b> starts with the string +"< forbid " the following sequence of characters is taken as a list of +forbidden modifiers. For example, in the test files that must not use UTF or +Unicode property support, this line appears: +<pre> + < forbid 8W +</pre> +This locks out the /8 and /W modifiers. An immediate error is given if they are +subsequently encountered. If the character string contains < but not >, all the +multi-character modifiers that begin with < are locked out. Otherwise, such +modifiers must be explicitly listed, for example: +<pre> + < forbid <JS><cr> +</pre> +There must be a single space between < and "forbid" for this feature to be +recognised. If there is not, the line is interpreted either as a request to +re-load a pre-compiled pattern (see "SAVING AND RELOADING COMPILED PATTERNS" +below) or, if there is a another < character, as a pattern that uses < as its +delimiter. +</P> +<br><a name="SEC7" href="#TOC1">DATA LINES</a><br> +<P> +Before each data line is passed to <b>pcre[16|32]_exec()</b>, leading and trailing +white space is removed, and it is then scanned for \ escapes. Some of these +are pretty esoteric features, intended for checking out some of the more +complicated features of PCRE. If you are just testing "ordinary" regular +expressions, you probably don't need any of these. The following escapes are +recognized: +<pre> + \a alarm (BEL, \x07) + \b backspace (\x08) + \e escape (\x27) + \f form feed (\x0c) + \n newline (\x0a) + \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits) + \r carriage return (\x0d) + \t tab (\x09) + \v vertical tab (\x0b) + \nnn octal character (up to 3 octal digits); always + a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode + \o{dd...} octal character (any number of octal digits} + \xhh hexadecimal byte (up to 2 hex digits) + \x{hh...} hexadecimal character (any number of hex digits) + \A pass the PCRE_ANCHORED option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \B pass the PCRE_NOTBOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \Cdd call pcre[16|32]_copy_substring() for substring dd after a successful match (number less than 32) + \Cname call pcre[16|32]_copy_named_substring() for substring "name" after a successful match (name termin- + ated by next non alphanumeric character) + \C+ show the current captured substrings at callout time + \C- do not supply a callout function + \C!n return 1 instead of 0 when callout number n is reached + \C!n!m return 1 instead of 0 when callout number n is reached for the nth time + \C*n pass the number n (may be negative) as callout data; this is used as the callout return value + \D use the <b>pcre[16|32]_dfa_exec()</b> match function + \F only shortest match for <b>pcre[16|32]_dfa_exec()</b> + \Gdd call pcre[16|32]_get_substring() for substring dd after a successful match (number less than 32) + \Gname call pcre[16|32]_get_named_substring() for substring "name" after a successful match (name termin- + ated by next non-alphanumeric character) + \Jdd set up a JIT stack of dd kilobytes maximum (any number of digits) + \L call pcre[16|32]_get_substringlist() after a successful match + \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings + \N pass the PCRE_NOTEMPTY option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>; if used twice, pass the + PCRE_NOTEMPTY_ATSTART option + \Odd set the size of the output vector passed to <b>pcre[16|32]_exec()</b> to dd (any number of digits) + \P pass the PCRE_PARTIAL_SOFT option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>; if used twice, pass the + PCRE_PARTIAL_HARD option + \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits) + \R pass the PCRE_DFA_RESTART option to <b>pcre[16|32]_dfa_exec()</b> + \S output details of memory get/free calls during matching + \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \Z pass the PCRE_NOTEOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \>dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i> + argument for <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> + \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> +</pre> +The use of \x{hh...} is not dependent on the use of the <b>/8</b> modifier on +the pattern. It is recognized always. There may be any number of hexadecimal +digits inside the braces; invalid values provoke error messages. +</P> +<P> +Note that \xhh specifies one byte rather than one character in UTF-8 mode; +this makes it possible to construct invalid UTF-8 sequences for testing +purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in +UTF-8 mode, generating more than one byte if the value is greater than 127. +When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte +for values less than 256, and causes an error for greater values. +</P> +<P> +In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it +possible to construct invalid UTF-16 sequences for testing purposes. +</P> +<P> +In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This makes it +possible to construct invalid UTF-32 sequences for testing purposes. +</P> +<P> +The escapes that specify line ending sequences are literal strings, exactly as +shown. No more than one newline setting should be present in any data line. +</P> +<P> +A backslash followed by anything else just escapes the anything else. If +the very last character is a backslash, it is ignored. This gives a way of +passing an empty line as data, since a real empty line terminates the data +input. +</P> +<P> +The <b>\J</b> escape provides a way of setting the maximum stack size that is +used by the just-in-time optimization code. It is ignored if JIT optimization +is not being used. Providing a stack that is larger than the default 32K is +necessary only for very complicated patterns. +</P> +<P> +If \M is present, <b>pcretest</b> calls <b>pcre[16|32]_exec()</b> several times, +with different values in the <i>match_limit</i> and <i>match_limit_recursion</i> +fields of the <b>pcre[16|32]_extra</b> data structure, until it finds the minimum +numbers for each parameter that allow <b>pcre[16|32]_exec()</b> to complete without +error. Because this is testing a specific feature of the normal interpretive +<b>pcre[16|32]_exec()</b> execution, the use of any JIT optimization that might +have been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled. +</P> +<P> +The <i>match_limit</i> number is a measure of the amount of backtracking +that takes place, and checking it out can be instructive. For most simple +matches, the number is quite small, but for patterns with very large numbers of +matching possibilities, it can become large very quickly with increasing length +of subject string. The <i>match_limit_recursion</i> number is a measure of how +much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is +needed to complete the match attempt. +</P> +<P> +When \O is used, the value specified may be higher or lower than the size set +by the <b>-O</b> command line option (or defaulted to 45); \O applies only to +the call of <b>pcre[16|32]_exec()</b> for the line in which it appears. +</P> +<P> +If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper +API to be used, the only option-setting sequences that have any effect are \B, +\N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, +to be passed to <b>regexec()</b>. +</P> +<br><a name="SEC8" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> +<P> +By default, <b>pcretest</b> uses the standard PCRE matching function, +<b>pcre[16|32]_exec()</b> to match each data line. PCRE also supports an +alternative matching function, <b>pcre[16|32]_dfa_test()</b>, which operates in a +different way, and has some restrictions. The differences between the two +functions are described in the +<a href="pcrematching.html"><b>pcrematching</b></a> +documentation. +</P> +<P> +If a data line contains the \D escape sequence, or if the command line +contains the <b>-dfa</b> option, the alternative matching function is used. +This function finds all possible matches at a given point. If, however, the \F +escape sequence is present in the data line, it stops after the first match is +found. This is always the shortest possible match. +</P> +<br><a name="SEC9" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br> +<P> +This section describes the output when the normal matching function, +<b>pcre[16|32]_exec()</b>, is being used. +</P> +<P> +When a match succeeds, <b>pcretest</b> outputs the list of captured substrings +that <b>pcre[16|32]_exec()</b> returns, starting with number 0 for the string that +matched the whole pattern. Otherwise, it outputs "No match" when the return is +PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching +substring when <b>pcre[16|32]_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that +this is the entire substring that was inspected during the partial match; it +may include characters before the actual match start if a lookbehind assertion, +\K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs +the PCRE negative error number and a short descriptive phrase. If the error is +a failed UTF string check, the offset of the start of the failing character and +the reason code are also output, provided that the size of the output vector is +at least two. Here is an example of an interactive <b>pcretest</b> run. +<pre> + $ pcretest + PCRE version 8.13 2011-04-30 + + re> /^abc(\d+)/ + data> abc123 + 0: abc123 + 1: 123 + data> xyz + No match +</pre> +Unset capturing substrings that are not followed by one that is set are not +returned by <b>pcre[16|32]_exec()</b>, and are not shown by <b>pcretest</b>. In the +following example, there are two capturing substrings, but when the first data +line is matched, the second, unset substring is not shown. An "internal" unset +substring is shown as "<unset>", as for the second data line. +<pre> + re> /(a)|(b)/ + data> a + 0: a + 1: a + data> b + 0: b + 1: <unset> + 2: b +</pre> +If the strings contain any non-printing characters, they are output as \xhh +escapes if the value is less than 256 and UTF mode is not set. Otherwise they +are output as \x{hh...} escapes. See below for the definition of non-printing +characters. If the pattern has the <b>/+</b> modifier, the output for substring +0 is followed by the the rest of the subject string, identified by "0+" like +this: +<pre> + re> /cat/+ + data> cataract + 0: cat + 0+ aract +</pre> +If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive +matching attempts are output in sequence, like this: +<pre> + re> /\Bi(\w\w)/g + data> Mississippi + 0: iss + 1: ss + 0: iss + 1: ss + 0: ipp + 1: pp +</pre> +"No match" is output only if the first match attempt fails. Here is an example +of a failure message (the offset 4 that is specified by \>4 is past the end of +the subject string): +<pre> + re> /xyz/ + data> xyz\>4 + Error -24 (bad offset value) +</PRE> +</P> +<P> +If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a +data line that is successfully matched, the substrings extracted by the +convenience functions are output with C, G, or L after the string number +instead of a colon. This is in addition to the normal full list. The string +length (that is, the return from the extraction function) is given in +parentheses after each string for <b>\C</b> and <b>\G</b>. +</P> +<P> +Note that whereas patterns can be continued over several lines (a plain ">" +prompt is used for continuations), data lines may not. However newlines can be +included in data by means of the \n escape (or \r, \r\n, etc., depending on +the newline sequence setting). +</P> +<br><a name="SEC10" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> +<P> +When the alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, is used (by +means of the \D escape sequence or the <b>-dfa</b> command line option), the +output consists of a list of all the matches that start at the first point in +the subject where there is at least one match. For example: +<pre> + re> /(tang|tangerine|tan)/ + data> yellow tangerine\D + 0: tangerine + 1: tang + 2: tan +</pre> +(Using the normal matching function on this data finds only "tang".) The +longest matching string is always given first (and numbered zero). After a +PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the +partially matching substring. (Note that this is the entire substring that was +inspected during the partial match; it may include characters before the actual +match start if a lookbehind assertion, \K, \b, or \B was involved.) +</P> +<P> +If <b>/g</b> is present on the pattern, the search for further matches resumes +at the end of the longest match. For example: +<pre> + re> /(tang|tangerine|tan)/g + data> yellow tangerine and tangy sultana\D + 0: tangerine + 1: tang + 2: tan + 0: tang + 1: tan + 0: tan +</pre> +Since the matching function does not support substring capture, the escape +sequences that are concerned with captured substrings are not relevant. +</P> +<br><a name="SEC11" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br> +<P> +When the alternative matching function has given the PCRE_ERROR_PARTIAL return, +indicating that the subject partially matched the pattern, you can restart the +match with additional subject data by means of the \R escape sequence. For +example: +<pre> + re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ + data> 23ja\P\D + Partial match: 23ja + data> n05\R\D + 0: n05 +</pre> +For further information about partial matching, see the +<a href="pcrepartial.html"><b>pcrepartial</b></a> +documentation. +</P> +<br><a name="SEC12" href="#TOC1">CALLOUTS</a><br> +<P> +If the pattern contains any callout requests, <b>pcretest</b>'s callout function +is called during matching. This works with both matching functions. By default, +the called function displays the callout number, the start and current +positions in the text at the callout time, and the next pattern item to be +tested. For example: +<pre> + --->pqrabcdef + 0 ^ ^ \d +</pre> +This output indicates that callout number 0 occurred for a match attempt +starting at the fourth character of the subject string, when the pointer was at +the seventh character of the data, and when the next pattern item was \d. Just +one circumflex is output if the start and current positions are the same. +</P> +<P> +Callouts numbered 255 are assumed to be automatic callouts, inserted as a +result of the <b>/C</b> pattern modifier. In this case, instead of showing the +callout number, the offset in the pattern, preceded by a plus, is output. For +example: +<pre> + re> /\d?[A-E]\*/C + data> E* + --->E* + +0 ^ \d? + +3 ^ [A-E] + +8 ^^ \* + +10 ^ ^ + 0: E* +</pre> +If a pattern contains (*MARK) items, an additional line is output whenever +a change of latest mark is passed to the callout function. For example: +<pre> + re> /a(*MARK:X)bc/C + data> abc + --->abc + +0 ^ a + +1 ^^ (*MARK:X) + +10 ^^ b + Latest Mark: X + +11 ^ ^ c + +12 ^ ^ + 0: abc +</pre> +The mark changes between matching "a" and "b", but stays the same for the rest +of the match, so nothing more is output. If, as a result of backtracking, the +mark reverts to being unset, the text "<unset>" is output. +</P> +<P> +The callout function in <b>pcretest</b> returns zero (carry on matching) by +default, but you can use a \C item in a data line (as described above) to +change this and other parameters of the callout. +</P> +<P> +Inserting callouts can be helpful when using <b>pcretest</b> to check +complicated regular expressions. For further information about callouts, see +the +<a href="pcrecallout.html"><b>pcrecallout</b></a> +documentation. +</P> +<br><a name="SEC13" href="#TOC1">NON-PRINTING CHARACTERS</a><br> +<P> +When <b>pcretest</b> is outputting text in the compiled version of a pattern, +bytes other than 32-126 are always treated as non-printing characters are are +therefore shown as hex escapes. +</P> +<P> +When <b>pcretest</b> is outputting text that is a matched part of a subject +string, it behaves in the same way, unless a different locale has been set for +the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b> +function to distinguish printing and non-printing characters. +</P> +<br><a name="SEC14" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br> +<P> +The facilities described in this section are not available when the POSIX +interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is +specified. +</P> +<P> +When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a +compiled pattern to a file, by following the modifiers with > and a file name. +For example: +<pre> + /pattern/im >/some/file +</pre> +See the +<a href="pcreprecompile.html"><b>pcreprecompile</b></a> +documentation for a discussion about saving and re-using compiled patterns. +Note that if the pattern was successfully studied with JIT optimization, the +JIT data cannot be saved. +</P> +<P> +The data that is written is binary. The first eight bytes are the length of the +compiled pattern data followed by the length of the optional study data, each +written as four bytes in big-endian order (most significant byte first). If +there is no study data (either the pattern was not studied, or studying did not +return any data), the second length is zero. The lengths are followed by an +exact copy of the compiled pattern. If there is additional study data, this +(excluding any JIT data) follows immediately after the compiled pattern. After +writing the file, <b>pcretest</b> expects to read a new pattern. +</P> +<P> +A saved pattern can be reloaded into <b>pcretest</b> by specifying < and a file +name instead of a pattern. There must be no space between < and the file name, +which must not contain a < character, as otherwise <b>pcretest</b> will +interpret the line as a pattern delimited by < characters. For example: +<pre> + re> </some/file + Compiled pattern loaded from /some/file + No study data +</pre> +If the pattern was previously studied with the JIT optimization, the JIT +information cannot be saved and restored, and so is lost. When the pattern has +been loaded, <b>pcretest</b> proceeds to read data lines in the usual way. +</P> +<P> +You can copy a file written by <b>pcretest</b> to a different host and reload it +there, even if the new host has opposite endianness to the one on which the +pattern was compiled. For example, you can compile on an i86 machine and run on +a SPARC machine. When a pattern is reloaded on a host with different +endianness, the confirmation message is changed to: +<pre> + Compiled pattern (byte-inverted) loaded from /some/file +</pre> +The test suite contains some saved pre-compiled patterns with different +endianness. These are reloaded using "<!" instead of just "<". This suppresses +the "(byte-inverted)" text so that the output is the same on all hosts. It also +forces debugging output once the pattern has been reloaded. +</P> +<P> +File names for saving and reloading can be absolute or relative, but note that +the shell facility of expanding a file name that starts with a tilde (~) is not +available. +</P> +<P> +The ability to save and reload files in <b>pcretest</b> is intended for testing +and experimentation. It is not intended for production use because only a +single pattern can be written to a file. Furthermore, there is no facility for +supplying custom character tables for use with a reloaded pattern. If the +original pattern was compiled with custom tables, an attempt to match a subject +string using a reloaded pattern is likely to cause <b>pcretest</b> to crash. +Finally, if you attempt to load a file that is not in the correct format, the +result is undefined. +</P> +<br><a name="SEC15" href="#TOC1">SEE ALSO</a><br> +<P> +<b>pcre</b>(3), <b>pcre16</b>(3), <b>pcre32</b>(3), <b>pcreapi</b>(3), +<b>pcrecallout</b>(3), +<b>pcrejit</b>, <b>pcrematching</b>(3), <b>pcrepartial</b>(d), +<b>pcrepattern</b>(3), <b>pcreprecompile</b>(3). +</P> +<br><a name="SEC16" href="#TOC1">AUTHOR</a><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><a name="SEC17" href="#TOC1">REVISION</a><br> +<P> +Last updated: 09 February 2014 +<br> +Copyright © 1997-2014 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> diff --git a/doc/html/pcreunicode.html b/doc/html/pcreunicode.html new file mode 100644 index 0000000..ab36bc6 --- /dev/null +++ b/doc/html/pcreunicode.html @@ -0,0 +1,262 @@ +<html> +<head> +<title>pcreunicode specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +<h1>pcreunicode man page</h1> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> +<p> +This page is part of the PCRE HTML documentation. It was generated automatically +from the original man page. If there is any nonsense in it, please consult the +man page, in case the conversion went wrong. +<br> +<br><b> +UTF-8, UTF-16, UTF-32, AND UNICODE PROPERTY SUPPORT +</b><br> +<P> +As well as UTF-8 support, PCRE also supports UTF-16 (from release 8.30) and +UTF-32 (from release 8.32), by means of two additional libraries. They can be +built as well as, or instead of, the 8-bit library. +</P> +<br><b> +UTF-8 SUPPORT +</b><br> +<P> +In order process UTF-8 strings, you must build PCRE's 8-bit library with UTF +support, and, in addition, you must call +<a href="pcre_compile.html"><b>pcre_compile()</b></a> +with the PCRE_UTF8 option flag, or the pattern must start with the sequence +(*UTF8) or (*UTF). When either of these is the case, both the pattern and any +subject strings that are matched against it are treated as UTF-8 strings +instead of strings of individual 1-byte characters. +</P> +<br><b> +UTF-16 AND UTF-32 SUPPORT +</b><br> +<P> +In order process UTF-16 or UTF-32 strings, you must build PCRE's 16-bit or +32-bit library with UTF support, and, in addition, you must call +<a href="pcre16_compile.html"><b>pcre16_compile()</b></a> +or +<a href="pcre32_compile.html"><b>pcre32_compile()</b></a> +with the PCRE_UTF16 or PCRE_UTF32 option flag, as appropriate. Alternatively, +the pattern must start with the sequence (*UTF16), (*UTF32), as appropriate, or +(*UTF), which can be used with either library. When UTF mode is set, both the +pattern and any subject strings that are matched against it are treated as +UTF-16 or UTF-32 strings instead of strings of individual 16-bit or 32-bit +characters. +</P> +<br><b> +UTF SUPPORT OVERHEAD +</b><br> +<P> +If you compile PCRE with UTF support, but do not use it at run time, the +library will be a bit bigger, but the additional run time overhead is limited +to testing the PCRE_UTF[8|16|32] flag occasionally, so should not be very big. +</P> +<br><b> +UNICODE PROPERTY SUPPORT +</b><br> +<P> +If PCRE is built with Unicode character property support (which implies UTF +support), the escape sequences \p{..}, \P{..}, and \X can be used. +The available properties that can be tested are limited to the general +category properties such as Lu for an upper case letter or Nd for a decimal +number, the Unicode script names such as Arabic or Han, and the derived +properties Any and L&. Full lists is given in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +and +<a href="pcresyntax.html"><b>pcresyntax</b></a> +documentation. Only the short names for properties are supported. For example, +\p{L} matches a letter. Its Perl synonym, \p{Letter}, is not supported. +Furthermore, in Perl, many properties may optionally be prefixed by "Is", for +compatibility with Perl 5.6. PCRE does not support this. +<a name="utf8strings"></a></P> +<br><b> +Validity of UTF-8 strings +</b><br> +<P> +When you set the PCRE_UTF8 flag, the byte strings passed as patterns and +subjects are (by default) checked for validity on entry to the relevant +functions. The entire string is checked before any other processing takes +place. From release 7.3 of PCRE, the check is according the rules of RFC 3629, +which are themselves derived from the Unicode specification. Earlier releases +of PCRE followed the rules of RFC 2279, which allows the full range of 31-bit +values (0 to 0x7FFFFFFF). The current check allows only values in the range U+0 +to U+10FFFF, excluding the surrogate area. (From release 8.33 the so-called +"non-character" code points are no longer excluded because Unicode corrigendum +#9 makes it clear that they should not be.) +</P> +<P> +Characters in the "Surrogate Area" of Unicode are reserved for use by UTF-16, +where they are used in pairs to encode codepoints with values greater than +0xFFFF. The code points that are encoded by UTF-16 pairs are available +independently in the UTF-8 and UTF-32 encodings. (In other words, the whole +surrogate thing is a fudge for UTF-16 which unfortunately messes up UTF-8 and +UTF-32.) +</P> +<P> +If an invalid UTF-8 string is passed to PCRE, an error return is given. At +compile time, the only additional information is the offset to the first byte +of the failing character. The run-time functions <b>pcre_exec()</b> and +<b>pcre_dfa_exec()</b> also pass back this information, as well as a more +detailed reason code if the caller has provided memory in which to do this. +</P> +<P> +In some situations, you may already know that your strings are valid, and +therefore want to skip these checks in order to improve performance, for +example in the case of a long subject string that is being scanned repeatedly. +If you set the PCRE_NO_UTF8_CHECK flag at compile time or at run time, PCRE +assumes that the pattern or subject it is given (respectively) contains only +valid UTF-8 codes. In this case, it does not diagnose an invalid UTF-8 string. +</P> +<P> +Note that passing PCRE_NO_UTF8_CHECK to <b>pcre_compile()</b> just disables the +check for the pattern; it does not also apply to subject strings. If you want +to disable the check for a subject string you must pass this option to +<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. +</P> +<P> +If you pass an invalid UTF-8 string when PCRE_NO_UTF8_CHECK is set, the result +is undefined and your program may crash. +<a name="utf16strings"></a></P> +<br><b> +Validity of UTF-16 strings +</b><br> +<P> +When you set the PCRE_UTF16 flag, the strings of 16-bit data units that are +passed as patterns and subjects are (by default) checked for validity on entry +to the relevant functions. Values other than those in the surrogate range +U+D800 to U+DFFF are independent code points. Values in the surrogate range +must be used in pairs in the correct manner. +</P> +<P> +If an invalid UTF-16 string is passed to PCRE, an error return is given. At +compile time, the only additional information is the offset to the first data +unit of the failing character. The run-time functions <b>pcre16_exec()</b> and +<b>pcre16_dfa_exec()</b> also pass back this information, as well as a more +detailed reason code if the caller has provided memory in which to do this. +</P> +<P> +In some situations, you may already know that your strings are valid, and +therefore want to skip these checks in order to improve performance. If you set +the PCRE_NO_UTF16_CHECK flag at compile time or at run time, PCRE assumes that +the pattern or subject it is given (respectively) contains only valid UTF-16 +sequences. In this case, it does not diagnose an invalid UTF-16 string. +However, if an invalid string is passed, the result is undefined. +<a name="utf32strings"></a></P> +<br><b> +Validity of UTF-32 strings +</b><br> +<P> +When you set the PCRE_UTF32 flag, the strings of 32-bit data units that are +passed as patterns and subjects are (by default) checked for validity on entry +to the relevant functions. This check allows only values in the range U+0 +to U+10FFFF, excluding the surrogate area U+D800 to U+DFFF. +</P> +<P> +If an invalid UTF-32 string is passed to PCRE, an error return is given. At +compile time, the only additional information is the offset to the first data +unit of the failing character. The run-time functions <b>pcre32_exec()</b> and +<b>pcre32_dfa_exec()</b> also pass back this information, as well as a more +detailed reason code if the caller has provided memory in which to do this. +</P> +<P> +In some situations, you may already know that your strings are valid, and +therefore want to skip these checks in order to improve performance. If you set +the PCRE_NO_UTF32_CHECK flag at compile time or at run time, PCRE assumes that +the pattern or subject it is given (respectively) contains only valid UTF-32 +sequences. In this case, it does not diagnose an invalid UTF-32 string. +However, if an invalid string is passed, the result is undefined. +</P> +<br><b> +General comments about UTF modes +</b><br> +<P> +1. Codepoints less than 256 can be specified in patterns by either braced or +unbraced hexadecimal escape sequences (for example, \x{b3} or \xb3). Larger +values have to use braced sequences. +</P> +<P> +2. Octal numbers up to \777 are recognized, and in UTF-8 mode they match +two-byte characters for values greater than \177. +</P> +<P> +3. Repeat quantifiers apply to complete UTF characters, not to individual +data units, for example: \x{100}{3}. +</P> +<P> +4. The dot metacharacter matches one UTF character instead of a single data +unit. +</P> +<P> +5. The escape sequence \C can be used to match a single byte in UTF-8 mode, or +a single 16-bit data unit in UTF-16 mode, or a single 32-bit data unit in +UTF-32 mode, but its use can lead to some strange effects because it breaks up +multi-unit characters (see the description of \C in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation). The use of \C is not supported in the alternative matching +function <b>pcre[16|32]_dfa_exec()</b>, nor is it supported in UTF mode by the +JIT optimization of <b>pcre[16|32]_exec()</b>. If JIT optimization is requested +for a UTF pattern that contains \C, it will not succeed, and so the matching +will be carried out by the normal interpretive function. +</P> +<P> +6. The character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly +test characters of any code value, but, by default, the characters that PCRE +recognizes as digits, spaces, or word characters remain the same set as in +non-UTF mode, all with values less than 256. This remains true even when PCRE +is built to include Unicode property support, because to do otherwise would +slow down PCRE in many common cases. Note in particular that this applies to +\b and \B, because they are defined in terms of \w and \W. If you really +want to test for a wider sense of, say, "digit", you can use explicit Unicode +property tests such as \p{Nd}. Alternatively, if you set the PCRE_UCP option, +the way that the character escapes work is changed so that Unicode properties +are used to determine which characters match. There are more details in the +section on +<a href="pcrepattern.html#genericchartypes">generic character types</a> +in the +<a href="pcrepattern.html"><b>pcrepattern</b></a> +documentation. +</P> +<P> +7. Similarly, characters that match the POSIX named character classes are all +low-valued characters, unless the PCRE_UCP option is set. +</P> +<P> +8. However, the horizontal and vertical white space matching escapes (\h, \H, +\v, and \V) do match all the appropriate Unicode characters, whether or not +PCRE_UCP is set. +</P> +<P> +9. Case-insensitive matching applies only to characters whose values are less +than 128, unless PCRE is built with Unicode property support. A few Unicode +characters such as Greek sigma have more than two codepoints that are +case-equivalent. Up to and including PCRE release 8.31, only one-to-one case +mappings were supported, but later releases (with Unicode property support) do +treat as case-equivalent all versions of characters such as Greek sigma. +</P> +<br><b> +AUTHOR +</b><br> +<P> +Philip Hazel +<br> +University Computing Service +<br> +Cambridge CB2 3QH, England. +<br> +</P> +<br><b> +REVISION +</b><br> +<P> +Last updated: 27 February 2013 +<br> +Copyright © 1997-2013 University of Cambridge. +<br> +<p> +Return to the <a href="index.html">PCRE index page</a>. +</p> |