summaryrefslogtreecommitdiff
path: root/NEWS
diff options
context:
space:
mode:
Diffstat (limited to 'NEWS')
-rw-r--r--NEWS693
1 files changed, 693 insertions, 0 deletions
diff --git a/NEWS b/NEWS
new file mode 100644
index 0000000..6331e99
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,693 @@
+News about PCRE releases
+------------------------
+
+Release 8.35 04-April-2014
+--------------------------
+
+There have been performance improvements for classes containing non-ASCII
+characters and the "auto-possessification" feature has been extended. Other
+minor improvements have been implemented and bugs fixed. There is a new callout
+feature to enable applications to do detailed stack checks at compile time, to
+avoid running out of stack for deeply nested parentheses. The JIT compiler has
+been extended with experimental support for ARM-64, MIPS-64, and PPC-LE.
+
+
+Release 8.34 15-December-2013
+-----------------------------
+
+As well as fixing the inevitable bugs, performance has been improved by
+refactoring and extending the amount of "auto-possessification" that PCRE does.
+Other notable changes:
+
+. Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
+ an empty string. If it can, pcretest shows this in its information output.
+
+. A back reference to a named subpattern when there is more than one of the
+ same name now checks them in the order in which they appear in the pattern.
+ The first one that is set is used for the reference. Previously only the
+ first one was inspected. This change makes PCRE more compatible with Perl.
+
+. Unicode character properties were updated from Unicode 6.3.0.
+
+. The character VT has been added to the set of characters that match \s and
+ are generally treated as white space, following this same change in Perl
+ 5.18. There is now no difference between "Perl space" and "POSIX space".
+
+. Perl has changed its handling of \8 and \9. If there is no previously
+ encountered capturing group of those numbers, they are treated as the
+ literal characters 8 and 9 instead of a binary zero followed by the
+ literals. PCRE now does the same.
+
+. Following Perl, added \o{} to specify codepoints in octal, making it
+ possible to specify values greater than 0777 and also making them
+ unambiguous.
+
+. In UCP mode, \s was not matching two of the characters that Perl matches,
+ namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
+ were matched by \h.
+
+. Add JIT support for the 64 bit TileGX architecture.
+
+. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
+ [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
+ does in Unicode mode.
+
+. Perl no longer allows group names to start with digits, so I have made this
+ change also in PCRE.
+
+. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
+ mean "start of word" and "end of word", respectively, as a transition aid.
+
+
+Release 8.33 28-May-2013
+--------------------------
+
+A number of bugs are fixed, and some performance improvements have been made.
+There are also some new features, of which these are the most important:
+
+. The behaviour of the backtracking verbs has been rationalized and
+ documented in more detail.
+
+. JIT now supports callouts and all of the backtracking verbs.
+
+. Unicode validation has been updated in the light of Unicode Corrigendum #9,
+ which points out that "non characters" are not "characters that may not
+ appear in Unicode strings" but rather "characters that are reserved for
+ internal use and have only local meaning".
+
+. (*LIMIT_MATCH=d) and (*LIMIT_RECURSION=d) have been added so that the
+ creator of a pattern can specify lower (but not higher) limits for the
+ matching process.
+
+. The PCRE_NEVER_UTF option is available to prevent pattern-writers from using
+ the (*UTF) feature, as this could be a security issue.
+
+
+Release 8.32 30-November-2012
+-----------------------------
+
+This release fixes a number of bugs, but also has some new features. These are
+the highlights:
+
+. There is now support for 32-bit character strings and UTF-32. Like the
+ 16-bit support, this is done by compiling a separate 32-bit library.
+
+. \X now matches a Unicode extended grapheme cluster.
+
+. Case-independent matching of Unicode characters that have more than one
+ "other case" now makes all three (or more) characters equivalent. This
+ applies, for example, to Greek Sigma, which has two lowercase versions.
+
+. Unicode character properties are updated to Unicode 6.2.0.
+
+. The EBCDIC support, which had decayed, has had a spring clean.
+
+. A number of JIT optimizations have been added, which give faster JIT
+ execution speed. In addition, a new direct interface to JIT execution is
+ available. This bypasses some of the sanity checks of pcre_exec() to give a
+ noticeable speed-up.
+
+. A number of issues in pcregrep have been fixed, making it more compatible
+ with GNU grep. In particular, --exclude and --include (and variants) apply
+ to all files now, not just those obtained from scanning a directory
+ recursively. In Windows environments, the default action for directories is
+ now "skip" instead of "read" (which provokes an error).
+
+. If the --only-matching (-o) option in pcregrep is specified multiple
+ times, each one causes appropriate output. For example, -o1 -o2 outputs the
+ substrings matched by the 1st and 2nd capturing parentheses. A separating
+ string can be specified by --om-separator (default empty).
+
+. When PCRE is built via Autotools using a version of gcc that has the
+ "visibility" feature, it is used to hide internal library functions that are
+ not part of the public API.
+
+
+Release 8.31 06-July-2012
+-------------------------
+
+This is mainly a bug-fixing release, with a small number of developments:
+
+. The JIT compiler now supports partial matching and the (*MARK) and
+ (*COMMIT) verbs.
+
+. PCRE_INFO_MAXLOOKBEHIND can be used to find the longest lookbehind in a
+ pattern.
+
+. There should be a performance improvement when using the heap instead of the
+ stack for recursion.
+
+. pcregrep can now be linked with libedit as an alternative to libreadline.
+
+. pcregrep now has a --file-list option where the list of files to scan is
+ given as a file.
+
+. pcregrep now recognizes binary files and there are related options.
+
+. The Unicode tables have been updated to 6.1.0.
+
+As always, the full list of changes is in the ChangeLog file.
+
+
+Release 8.30 04-February-2012
+-----------------------------
+
+Release 8.30 introduces a major new feature: support for 16-bit character
+strings, compiled as a separate library. There are a few changes to the
+8-bit library, in addition to some bug fixes.
+
+. The pcre_info() function, which has been obsolete for over 10 years, has
+ been removed.
+
+. When a compiled pattern was saved to a file and later reloaded on a host
+ with different endianness, PCRE used automatically to swap the bytes in some
+ of the data fields. With the advent of the 16-bit library, where more of this
+ swapping is needed, it is no longer done automatically. Instead, the bad
+ endianness is detected and a specific error is given. The user can then call
+ a new function called pcre_pattern_to_host_byte_order() (or an equivalent
+ 16-bit function) to do the swap.
+
+. In UTF-8 mode, the values 0xd800 to 0xdfff are not legal Unicode
+ code points and are now faulted. (They are the so-called "surrogates"
+ that are reserved for coding high values in UTF-16.)
+
+
+Release 8.21 12-Dec-2011
+------------------------
+
+This is almost entirely a bug-fix release. The only new feature is the ability
+to obtain the size of the memory used by the JIT compiler.
+
+
+Release 8.20 21-Oct-2011
+------------------------
+
+The main change in this release is the inclusion of Zoltan Herczeg's
+just-in-time compiler support, which can be accessed by building PCRE with
+--enable-jit. Large performance benefits can be had in many situations. 8.20
+also fixes an unfortunate bug that was introduced in 8.13 as well as tidying up
+a number of infelicities and differences from Perl.
+
+
+Release 8.13 16-Aug-2011
+------------------------
+
+This is mainly a bug-fix release. There has been a lot of internal refactoring.
+The Unicode tables have been updated. The only new feature in the library is
+the passing of *MARK information to callouts. Some additions have been made to
+pcretest to make testing easier and more comprehensive. There is a new option
+for pcregrep to adjust its internal buffer size.
+
+
+Release 8.12 15-Jan-2011
+------------------------
+
+This release fixes some bugs in pcregrep, one of which caused the tests to fail
+on 64-bit big-endian systems. There are no changes to the code of the library.
+
+
+Release 8.11 10-Dec-2010
+------------------------
+
+A number of bugs in the library and in pcregrep have been fixed. As always, see
+ChangeLog for details. The following are the non-bug-fix changes:
+
+. Added --match-limit and --recursion-limit to pcregrep.
+
+. Added an optional parentheses number to the -o and --only-matching options
+ of pcregrep.
+
+. Changed the way PCRE_PARTIAL_HARD affects the matching of $, \z, \Z, \b, and
+ \B.
+
+. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
+ bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
+
+. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
+ START_OPTIMIZE option, which is now allowed at compile time
+
+
+Release 8.10 25-Jun-2010
+------------------------
+
+There are two major additions: support for (*MARK) and friends, and the option
+PCRE_UCP, which changes the behaviour of \b, \d, \s, and \w (and their
+opposites) so that they make use of Unicode properties. There are also a number
+of lesser new features, and several bugs have been fixed. A new option,
+--line-buffered, has been added to pcregrep, for use when it is connected to
+pipes.
+
+
+Release 8.02 19-Mar-2010
+------------------------
+
+Another bug-fix release.
+
+
+Release 8.01 19-Jan-2010
+------------------------
+
+This is a bug-fix release. Several bugs in the code itself and some bugs and
+infelicities in the build system have been fixed.
+
+
+Release 8.00 19-Oct-09
+----------------------
+
+Bugs have been fixed in the library and in pcregrep. There are also some
+enhancements. Restrictions on patterns used for partial matching have been
+removed, extra information is given for partial matches, the partial matching
+process has been improved, and an option to make a partial match override a
+full match is available. The "study" process has been enhanced by finding a
+lower bound matching length. Groups with duplicate numbers may now have
+duplicated names without the use of PCRE_DUPNAMES. However, they may not have
+different names. The documentation has been revised to reflect these changes.
+The version number has been expanded to 3 digits as it is clear that the rate
+of change is not slowing down.
+
+
+Release 7.9 11-Apr-09
+---------------------
+
+Mostly bugfixes and tidies with just a couple of minor functional additions.
+
+
+Release 7.8 05-Sep-08
+---------------------
+
+More bug fixes, plus a performance improvement in Unicode character property
+lookup.
+
+
+Release 7.7 07-May-08
+---------------------
+
+This is once again mainly a bug-fix release, but there are a couple of new
+features.
+
+
+Release 7.6 28-Jan-08
+---------------------
+
+The main reason for having this release so soon after 7.5 is because it fixes a
+potential buffer overflow problem in pcre_compile() when run in UTF-8 mode. In
+addition, the CMake configuration files have been brought up to date.
+
+
+Release 7.5 10-Jan-08
+---------------------
+
+This is mainly a bug-fix release. However the ability to link pcregrep with
+libz or libbz2 and the ability to link pcretest with libreadline have been
+added. Also the --line-offsets and --file-offsets options were added to
+pcregrep.
+
+
+Release 7.4 21-Sep-07
+---------------------
+
+The only change of specification is the addition of options to control whether
+\R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
+Otherwise, the changes are bug fixes and a refactoring to reduce the number of
+relocations needed in a shared library. There have also been some documentation
+updates, in particular, some more information about using CMake to build PCRE
+has been added to the NON-UNIX-USE file.
+
+
+Release 7.3 28-Aug-07
+---------------------
+
+Most changes are bug fixes. Some that are not:
+
+1. There is some support for Perl 5.10's experimental "backtracking control
+ verbs" such as (*PRUNE).
+
+2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
+ restrictive in the strings it accepts.
+
+3. Checking for potential integer overflow has been made more dynamic, and as a
+ consequence there is no longer a hard limit on the size of a subpattern that
+ has a limited repeat count.
+
+4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
+ no longer advance by two characters instead of one when an unanchored match
+ fails at CRLF if there are explicit CR or LF matches within the pattern.
+ This gets rid of some anomalous effects that previously occurred.
+
+5. Some PCRE-specific settings for varying the newline options at the start of
+ a pattern have been added.
+
+
+Release 7.2 19-Jun-07
+---------------------
+
+WARNING: saved patterns that were compiled by earlier versions of PCRE must be
+recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
+and \V).
+
+Correction to the notes for 7.1: the note about shared libraries for Windows is
+wrong. Previously, three libraries were built, but each could function
+independently. For example, the pcreposix library also included all the
+functions from the basic pcre library. The change is that the three libraries
+are no longer independent. They are like the Unix libraries. To use the
+pcreposix functions, for example, you need to link with both the pcreposix and
+the basic pcre library.
+
+Some more features from Perl 5.10 have been added:
+
+ (?-n) and (?+n) relative references for recursion and subroutines.
+
+ (?(-n) and (?(+n) relative references as conditions.
+
+ \k{name} and \g{name} are synonyms for \k<name>.
+
+ \K to reset the start of the matched string; for example, (foo)\Kbar
+ matches bar preceded by foo, but only sets bar as the matched string.
+
+ (?| introduces a group where the capturing parentheses in each alternative
+ start from the same number; for example, (?|(abc)|(xyz)) sets capturing
+ parentheses number 1 in both cases.
+
+ \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
+
+
+Release 7.1 24-Apr-07
+---------------------
+
+There is only one new feature in this release: a linebreak setting of
+PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
+recognizes only CRLF, CR, and LF as linebreaks.
+
+A few bugs are fixed (see ChangeLog for details), but the major change is a
+complete re-implementation of the build system. This now has full Autotools
+support and so is now "standard" in some sense. It should help with compiling
+PCRE in a wide variety of environments.
+
+NOTE: when building shared libraries for Windows, three dlls are now built,
+called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
+included in a single dll.
+
+Another important change is that the dftables auxiliary program is no longer
+compiled and run at "make" time by default. Instead, a default set of character
+tables (assuming ASCII coding) is used. If you want to use dftables to generate
+the character tables as previously, add --enable-rebuild-chartables to the
+"configure" command. You must do this if you are compiling PCRE to run on a
+system that uses EBCDIC code.
+
+There is a discussion about character tables in the README file. The default is
+not to use dftables so that that there is no problem when cross-compiling.
+
+
+Release 7.0 19-Dec-06
+---------------------
+
+This release has a new major number because there have been some internal
+upheavals to facilitate the addition of new optimizations and other facilities,
+and to make subsequent maintenance and extension easier. Compilation is likely
+to be a bit slower, but there should be no major effect on runtime performance.
+Previously compiled patterns are NOT upwards compatible with this release. If
+you have saved compiled patterns from a previous release, you will have to
+re-compile them. Important changes that are visible to users are:
+
+1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
+ some more scripts.
+
+2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
+ sequence as a newline.
+
+3. The \R escape matches a single Unicode newline sequence as a single unit.
+
+4. New features that will appear in Perl 5.10 are now in PCRE. These include
+ alternative Perl syntax for named parentheses, and Perl syntax for
+ recursion.
+
+5. The C++ wrapper interface has been extended by the addition of a
+ QuoteMeta function and the ability to allow copy construction and
+ assignment.
+
+For a complete list of changes, see the ChangeLog file.
+
+
+Release 6.7 04-Jul-06
+---------------------
+
+The main additions to this release are the ability to use the same name for
+multiple sets of parentheses, and support for CRLF line endings in both the
+library and pcregrep (and in pcretest for testing).
+
+Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
+significantly reduced for certain subject strings.
+
+
+Release 6.5 01-Feb-06
+---------------------
+
+Important changes in this release:
+
+1. A number of new features have been added to pcregrep.
+
+2. The Unicode property tables have been updated to Unicode 4.1.0, and the
+ supported properties have been extended with script names such as "Arabic",
+ and the derived properties "Any" and "L&". This has necessitated a change to
+ the interal format of compiled patterns. Any saved compiled patterns that
+ use \p or \P must be recompiled.
+
+3. The specification of recursion in patterns has been changed so that all
+ recursive subpatterns are automatically treated as atomic groups. Thus, for
+ example, (?R) is treated as if it were (?>(?R)). This is necessary because
+ otherwise there are situations where recursion does not work.
+
+See the ChangeLog for a complete list of changes, which include a number of bug
+fixes and tidies.
+
+
+Release 6.0 07-Jun-05
+---------------------
+
+The release number has been increased to 6.0 because of the addition of several
+major new pieces of functionality.
+
+A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
+algorithm, has been added. This has a number of advantages for certain cases,
+though it does run more slowly, and lacks the ability to capture substrings. On
+the other hand, it does find all matches, not just the first, and it works
+better for partial matching. The pcrematching man page discusses the
+differences.
+
+The pcretest program has been enhanced so that it can make use of the new
+pcre_dfa_exec() matching function and the extra features it provides.
+
+The distribution now includes a C++ wrapper library. This is built
+automatically if a C++ compiler is found. The pcrecpp man page discusses this
+interface.
+
+The code itself has been re-organized into many more files, one for each
+function, so it no longer requires everything to be linked in when static
+linkage is used. As a consequence, some internal functions have had to have
+their names exposed. These functions all have names starting with _pcre_. They
+are undocumented, and are not intended for use by outside callers.
+
+The pcregrep program has been enhanced with new functionality such as
+multiline-matching and options for output more matching context. See the
+ChangeLog for a complete list of changes to the library and the utility
+programs.
+
+
+Release 5.0 13-Sep-04
+---------------------
+
+The licence under which PCRE is released has been changed to the more
+conventional "BSD" licence.
+
+In the code, some bugs have been fixed, and there are also some major changes
+in this release (which is why I've increased the number to 5.0). Some changes
+are internal rearrangements, and some provide a number of new facilities. The
+new features are:
+
+1. There's an "automatic callout" feature that inserts callouts before every
+ item in the regex, and there's a new callout field that gives the position
+ in the pattern - useful for debugging and tracing.
+
+2. The extra_data structure can now be used to pass in a set of character
+ tables at exec time. This is useful if compiled regex are saved and re-used
+ at a later time when the tables may not be at the same address. If the
+ default internal tables are used, the pointer saved with the compiled
+ pattern is now set to NULL, which means that you don't need to do anything
+ special unless you are using custom tables.
+
+3. It is possible, with some restrictions on the content of the regex, to
+ request "partial" matching. A special return code is given if all of the
+ subject string matched part of the regex. This could be useful for testing
+ an input field as it is being typed.
+
+4. There is now some optional support for Unicode character properties, which
+ means that the patterns items such as \p{Lu} and \X can now be used. Only
+ the general category properties are supported. If PCRE is compiled with this
+ support, an additional 90K data structure is include, which increases the
+ size of the library dramatically.
+
+5. There is support for saving compiled patterns and re-using them later.
+
+6. There is support for running regular expressions that were compiled on a
+ different host with the opposite endianness.
+
+7. The pcretest program has been extended to accommodate the new features.
+
+The main internal rearrangement is that sequences of literal characters are no
+longer handled as strings. Instead, each character is handled on its own. This
+makes some UTF-8 handling easier, and makes the support of partial matching
+possible. Compiled patterns containing long literal strings will be larger as a
+result of this change; I hope that performance will not be much affected.
+
+
+Release 4.5 01-Dec-03
+---------------------
+
+Again mainly a bug-fix and tidying release, with only a couple of new features:
+
+1. It's possible now to compile PCRE so that it does not use recursive
+function calls when matching. Instead it gets memory from the heap. This slows
+things down, but may be necessary on systems with limited stacks.
+
+2. UTF-8 string checking has been tightened to reject overlong sequences and to
+check that a starting offset points to the start of a character. Failure of the
+latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
+
+3. PCRE can now be compiled for systems that use EBCDIC code.
+
+
+Release 4.4 21-Aug-03
+---------------------
+
+This is mainly a bug-fix and tidying release. The only new feature is that PCRE
+checks UTF-8 strings for validity by default. There is an option to suppress
+this, just in case anybody wants that teeny extra bit of performance.
+
+
+Releases 4.1 - 4.3
+------------------
+
+Sorry, I forgot about updating the NEWS file for these releases. Please take a
+look at ChangeLog.
+
+
+Release 4.0 17-Feb-03
+---------------------
+
+There have been a lot of changes for the 4.0 release, adding additional
+functionality and mending bugs. Below is a list of the highlights of the new
+functionality. For full details of these features, please consult the
+documentation. For a complete list of changes, see the ChangeLog file.
+
+1. Support for Perl's \Q...\E escapes.
+
+2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
+package. They provide some syntactic sugar for simple cases of "atomic
+grouping".
+
+3. Support for the \G assertion. It is true when the current matching position
+is at the start point of the match.
+
+4. A new feature that provides some of the functionality that Perl provides
+with (?{...}). The facility is termed a "callout". The way it is done in PCRE
+is for the caller to provide an optional function, by setting pcre_callout to
+its entry point. To get the function called, the regex must include (?C) at
+appropriate points.
+
+5. Support for recursive calls to individual subpatterns. This makes it really
+easy to get totally confused.
+
+6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
+name a group.
+
+7. Several extensions to UTF-8 support; it is now fairly complete. There is an
+option for pcregrep to make it operate in UTF-8 mode.
+
+8. The single man page has been split into a number of separate man pages.
+These also give rise to individual HTML pages which are put in a separate
+directory. There is an index.html page that lists them all. Some hyperlinking
+between the pages has been installed.
+
+
+Release 3.5 15-Aug-01
+---------------------
+
+1. The configuring system has been upgraded to use later versions of autoconf
+and libtool. By default it builds both a shared and a static library if the OS
+supports it. You can use --disable-shared or --disable-static on the configure
+command if you want only one of them.
+
+2. The pcretest utility is now installed along with pcregrep because it is
+useful for users (to test regexs) and by doing this, it automatically gets
+relinked by libtool. The documentation has been turned into a man page, so
+there are now .1, .txt, and .html versions in /doc.
+
+3. Upgrades to pcregrep:
+ (i) Added long-form option names like gnu grep.
+ (ii) Added --help to list all options with an explanatory phrase.
+ (iii) Added -r, --recursive to recurse into sub-directories.
+ (iv) Added -f, --file to read patterns from a file.
+
+4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
+script, to force use of CR or LF instead of \n in the source. On non-Unix
+systems, the value can be set in config.h.
+
+5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
+absolute limit. Changed the text of the error message to make this clear, and
+likewise updated the man page.
+
+6. The limit of 99 on the number of capturing subpatterns has been removed.
+The new limit is 65535, which I hope will not be a "real" limit.
+
+
+Release 3.3 01-Aug-00
+---------------------
+
+There is some support for UTF-8 character strings. This is incomplete and
+experimental. The documentation describes what is and what is not implemented.
+Otherwise, this is just a bug-fixing release.
+
+
+Release 3.0 01-Feb-00
+---------------------
+
+1. A "configure" script is now used to configure PCRE for Unix systems. It
+builds a Makefile, a config.h file, and the pcre-config script.
+
+2. PCRE is built as a shared library by default.
+
+3. There is support for POSIX classes such as [:alpha:].
+
+5. There is an experimental recursion feature.
+
+----------------------------------------------------------------------------
+ IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
+
+Please note that there has been a change in the API such that a larger
+ovector is required at matching time, to provide some additional workspace.
+The new man page has details. This change was necessary in order to support
+some of the new functionality in Perl 5.005.
+
+ IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
+
+Another (I hope this is the last!) change has been made to the API for the
+pcre_compile() function. An additional argument has been added to make it
+possible to pass over a pointer to character tables built in the current
+locale by pcre_maketables(). To use the default tables, this new argument
+should be passed as NULL.
+
+ IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
+
+Yet another (and again I hope this really is the last) change has been made
+to the API for the pcre_exec() function. An additional argument has been
+added to make it possible to start the match other than at the start of the
+subject string. This is important if there are lookbehinds. The new man
+page has the details, but you just want to convert existing programs, all
+you need to do is to stick in a new fifth argument to pcre_exec(), with a
+value of zero. For example, change
+
+ pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
+to
+ pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
+
+****