summaryrefslogtreecommitdiff
path: root/doc/pcrebuild.3
diff options
context:
space:
mode:
Diffstat (limited to 'doc/pcrebuild.3')
-rw-r--r--doc/pcrebuild.3550
1 files changed, 550 insertions, 0 deletions
diff --git a/doc/pcrebuild.3 b/doc/pcrebuild.3
new file mode 100644
index 0000000..403f2ae
--- /dev/null
+++ b/doc/pcrebuild.3
@@ -0,0 +1,550 @@
+.TH PCREBUILD 3 "12 May 2013" "PCRE 8.33"
+.SH NAME
+PCRE - Perl-compatible regular expressions
+.
+.
+.SH "BUILDING PCRE"
+.rs
+.sp
+PCRE is distributed with a \fBconfigure\fP 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 \fBCMake\fP
+instead of \fBconfigure\fP. The text file
+.\" HTML <a href="README.txt">
+.\" </a>
+\fBREADME\fP
+.\"
+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 \fBCMake\fP and building "by
+hand") in the text file called
+.\" HTML <a href="NON-AUTOTOOLS-BUILD.txt">
+.\" </a>
+\fBNON-AUTOTOOLS-BUILD\fP.
+.\"
+You should consult this file as well as the
+.\" HTML <a href="README.txt">
+.\" </a>
+\fBREADME\fP
+.\"
+file if you are building in a non-Unix-like environment.
+.
+.
+.SH "PCRE BUILD-TIME OPTIONS"
+.rs
+.sp
+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 \fBconfigure\fP
+script, where the optional features are selected or deselected by providing
+options to \fBconfigure\fP before running the \fBmake\fP command. However, the
+same options can be selected in both Unix-like and non-Unix-like environments
+using the GUI facility of \fBcmake-gui\fP if you are using \fBCMake\fP instead
+of \fBconfigure\fP to build PCRE.
+.P
+If you are not using Autotools or \fBCMake\fP, option selection can be done by
+editing the \fBconfig.h\fP file, or by passing parameter settings to the
+compiler, as described in
+.\" HTML <a href="NON-AUTOTOOLS-BUILD.txt">
+.\" </a>
+\fBNON-AUTOTOOLS-BUILD\fP.
+.\"
+.P
+The complete list of options for \fBconfigure\fP (which includes the standard
+ones such as the selection of the installation directory) can be obtained by
+running
+.sp
+ ./configure --help
+.sp
+The following sections include descriptions of options whose names begin with
+--enable or --disable. These settings specify changes to the defaults for the
+\fBconfigure\fP command. Because of the way that \fBconfigure\fP 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.
+.
+.
+.SH "BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
+.rs
+.sp
+By default, a library called \fBlibpcre\fP 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 \fBlibpcre16\fP, 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
+.sp
+ --enable-pcre16
+.sp
+to the \fBconfigure\fP command. You can also build yet another separate
+library, called \fBlibpcre32\fP, 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
+.sp
+ --enable-pcre32
+.sp
+to the \fBconfigure\fP command. If you do not want the 8-bit library, add
+.sp
+ --disable-pcre8
+.sp
+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 \fBpcregrep\fP is
+an 8-bit program. None of these are built if you select only the 16-bit or
+32-bit libraries.
+.
+.
+.SH "BUILDING SHARED AND STATIC LIBRARIES"
+.rs
+.sp
+The Autotools PCRE building process uses \fBlibtool\fP to build both shared and
+static libraries by default. You can suppress one of these by adding one of
+.sp
+ --disable-shared
+ --disable-static
+.sp
+to the \fBconfigure\fP command, as required.
+.
+.
+.SH "C++ SUPPORT"
+.rs
+.sp
+By default, if the 8-bit library is being built, the \fBconfigure\fP 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
+.sp
+ --disable-cpp
+.sp
+to the \fBconfigure\fP command.
+.
+.
+.SH "UTF-8, UTF-16 AND UTF-32 SUPPORT"
+.rs
+.sp
+To build PCRE with support for UTF Unicode character strings, add
+.sp
+ --enable-utf
+.sp
+to the \fBconfigure\fP 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
+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
+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.
+.
+.
+.SH "UNICODE CHARACTER PROPERTY SUPPORT"
+.rs
+.sp
+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 \eP, \ep, and \eX, which refer to Unicode
+character properties, you must add
+.sp
+ --enable-unicode-properties
+.sp
+to the \fBconfigure\fP command. This implies UTF support, even if you have
+not explicitly requested it.
+.P
+Including Unicode property support adds around 30K of tables to the PCRE
+library. Only the general category properties such as \fILu\fP and \fINd\fP are
+supported. Details are given in the
+.\" HREF
+\fBpcrepattern\fP
+.\"
+documentation.
+.
+.
+.SH "JUST-IN-TIME COMPILER SUPPORT"
+.rs
+.sp
+Just-in-time compiler support is included in the build by specifying
+.sp
+ --enable-jit
+.sp
+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
+.\" HREF
+\fBpcrejit\fP
+.\"
+documentation for a discussion of JIT usage. When JIT support is enabled,
+pcregrep automatically makes use of it, unless you add
+.sp
+ --disable-pcregrep-jit
+.sp
+to the "configure" command.
+.
+.
+.SH "CODE VALUE OF NEWLINE"
+.rs
+.sp
+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
+.sp
+ --enable-newline-is-cr
+.sp
+to the \fBconfigure\fP command. There is also a --enable-newline-is-lf option,
+which explicitly specifies linefeed as the newline character.
+.sp
+Alternatively, you can specify that line endings are to be indicated by the two
+character sequence CRLF. If you want this, add
+.sp
+ --enable-newline-is-crlf
+.sp
+to the \fBconfigure\fP command. There is a fourth option, specified by
+.sp
+ --enable-newline-is-anycrlf
+.sp
+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
+.sp
+ --enable-newline-is-any
+.sp
+causes PCRE to recognize any Unicode newline sequence.
+.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.
+.
+.
+.SH "WHAT \eR MATCHES"
+.rs
+.sp
+By default, the sequence \eR in a pattern matches any Unicode newline sequence,
+whatever has been selected as the line ending sequence. If you specify
+.sp
+ --enable-bsr-anycrlf
+.sp
+the default is changed so that \eR matches only CR, LF, or CRLF. Whatever is
+selected when PCRE is built can be overridden when the library functions are
+called.
+.
+.
+.SH "POSIX MALLOC USAGE"
+.rs
+.sp
+When the 8-bit library is called through the POSIX interface (see the
+.\" HREF
+\fBpcreposix\fP
+.\"
+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 \fBmalloc()\fP 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
+.sp
+ --with-posix-malloc-threshold=20
+.sp
+to the \fBconfigure\fP command.
+.
+.
+.SH "HANDLING VERY LARGE PATTERNS"
+.rs
+.sp
+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
+.sp
+ --with-link-size=3
+.sp
+to the \fBconfigure\fP 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.
+.
+.
+.SH "AVOIDING EXCESSIVE STACK USAGE"
+.rs
+.sp
+When matching with the \fBpcre_exec()\fP function, PCRE implements backtracking
+by making recursive calls to an internal function called \fBmatch()\fP. 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
+.\" HREF
+\fBpcrestack\fP
+.\"
+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
+.sp
+ --disable-stack-for-recursion
+.sp
+to the \fBconfigure\fP command. With this configuration, PCRE will use the
+\fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP variables to call memory
+management functions. By default these point to \fBmalloc()\fP and
+\fBfree()\fP, but you can replace the pointers so that your own functions are
+used instead.
+.P
+Separate functions are provided rather than using \fBpcre_malloc\fP and
+\fBpcre_free\fP 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 \fBmalloc()\fP and \fBfree()\fP. PCRE runs noticeably more
+slowly when built in this way. This option affects only the \fBpcre_exec()\fP
+function; it is not relevant for \fBpcre_dfa_exec()\fP.
+.
+.
+.SH "LIMITING PCRE RESOURCE USAGE"
+.rs
+.sp
+Internally, PCRE has a function called \fBmatch()\fP, which it calls repeatedly
+(sometimes recursively) when matching a pattern with the \fBpcre_exec()\fP
+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 \fBpcre_exec()\fP. The limit can be changed
+at run time, as described in the
+.\" HREF
+\fBpcreapi\fP
+.\"
+documentation. The default is 10 million, but this can be changed by adding a
+setting such as
+.sp
+ --with-match-limit=500000
+.sp
+to the \fBconfigure\fP command. This setting has no effect on the
+\fBpcre_dfa_exec()\fP matching function.
+.P
+In some environments it is desirable to limit the depth of recursive calls of
+\fBmatch()\fP 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,
+.sp
+ --with-match-limit-recursion=10000
+.sp
+to the \fBconfigure\fP command. This value can also be overridden at run time.
+.
+.
+.SH "CREATING CHARACTER TABLES AT BUILD TIME"
+.rs
+.sp
+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 \fIpcre_chartables.c.dist\fP. These tables are for ASCII codes
+only. If you add
+.sp
+ --enable-rebuild-chartables
+.sp
+to the \fBconfigure\fP command, the distributed tables are no longer used.
+Instead, a program called \fBdftables\fP 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 \fBdftables\fP is run on the local host. If you need to
+create alternative tables when cross compiling, you will have to do so "by
+hand".)
+.
+.
+.SH "USING EBCDIC CODE"
+.rs
+.sp
+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
+.sp
+ --enable-ebcdic
+.sp
+to the \fBconfigure\fP 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
+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
+.sp
+ --enable-ebcdic-nl25
+.sp
+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 \fInot\fP
+chosen as LF is made to correspond to the Unicode NEL character (which, in
+Unicode, is 0x85).
+.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.
+.
+.
+.SH "PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT"
+.rs
+.sp
+By default, \fBpcregrep\fP reads all files as plain text. You can build it so
+that it recognizes files whose names end in \fB.gz\fP or \fB.bz2\fP, and reads
+them with \fBlibz\fP or \fBlibbz2\fP, respectively, by adding one or both of
+.sp
+ --enable-pcregrep-libz
+ --enable-pcregrep-libbz2
+.sp
+to the \fBconfigure\fP command. These options naturally require that the
+relevant libraries are installed on your system. Configuration will fail if
+they are not.
+.
+.
+.SH "PCREGREP BUFFER SIZE"
+.rs
+.sp
+\fBpcregrep\fP 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,
+.sp
+ --with-pcregrep-bufsize=50K
+.sp
+to the \fBconfigure\fP command. The caller of \fPpcregrep\fP can, however,
+override this value by specifying a run-time option.
+.
+.
+.SH "PCRETEST OPTION FOR LIBREADLINE SUPPORT"
+.rs
+.sp
+If you add
+.sp
+ --enable-pcretest-libreadline
+.sp
+to the \fBconfigure\fP command, \fBpcretest\fP is linked with the
+\fBlibreadline\fP library, and when its input is from a terminal, it reads it
+using the \fBreadline()\fP function. This provides line-editing and history
+facilities. Note that \fBlibreadline\fP is GPL-licensed, so if you distribute a
+binary of \fBpcretest\fP linked in this way, there may be licensing issues.
+.P
+Setting this option causes the \fB-lreadline\fP option to be added to the
+\fBpcretest\fP build. In many operating environments with a sytem-installed
+\fBlibreadline\fP 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 \fBlibreadline\fP says
+this:
+.sp
+ "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."
+.sp
+If your environment has not been set up so that an appropriate library is
+automatically included, you may need to add something like
+.sp
+ LIBS="-ncurses"
+.sp
+immediately before the \fBconfigure\fP command.
+.
+.
+.SH "DEBUGGING WITH VALGRIND SUPPORT"
+.rs
+.sp
+By adding the
+.sp
+ --enable-valgrind
+.sp
+option to to the \fBconfigure\fP 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.
+.
+.
+.SH "CODE COVERAGE REPORTING"
+.rs
+.sp
+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
+\fBlcov\fP version 1.6 or above. Then specify
+.sp
+ --enable-coverage
+.sp
+to the \fBconfigure\fP command and build PCRE in the usual way.
+.P
+Note that using \fBccache\fP (a caching C compiler) is incompatible with code
+coverage reporting. If you have configured \fBccache\fP to run automatically
+on your system, you must set the environment variable
+.sp
+ CCACHE_DISABLE=1
+.sp
+before running \fBmake\fP to build PCRE, so that \fBccache\fP is not used.
+.P
+When --enable-coverage is used, the following addition targets are added to the
+\fIMakefile\fP:
+.sp
+ make coverage
+.sp
+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".
+.sp
+ make coverage-reset
+.sp
+This zeroes the coverage counters, but does nothing else.
+.sp
+ make coverage-baseline
+.sp
+This captures baseline coverage information.
+.sp
+ make coverage-report
+.sp
+This creates the coverage report.
+.sp
+ make coverage-clean-report
+.sp
+This removes the generated coverage report without cleaning the coverage data
+itself.
+.sp
+ make coverage-clean-data
+.sp
+This removes the captured coverage data without removing the coverage files
+created at compile time (*.gcno).
+.sp
+ make coverage-clean
+.sp
+This cleans all coverage data including the generated coverage report. For more
+information about code coverage, see the \fBgcov\fP and \fBlcov\fP
+documentation.
+.
+.
+.SH "SEE ALSO"
+.rs
+.sp
+\fBpcreapi\fP(3), \fBpcre16\fP, \fBpcre32\fP, \fBpcre_config\fP(3).
+.
+.
+.SH AUTHOR
+.rs
+.sp
+.nf
+Philip Hazel
+University Computing Service
+Cambridge CB2 3QH, England.
+.fi
+.
+.
+.SH REVISION
+.rs
+.sp
+.nf
+Last updated: 12 May 2013
+Copyright (c) 1997-2013 University of Cambridge.
+.fi