ChangeLog for PCRE

 ------------------

 Version 7.9 11-Apr-09

 ---------------------

 1.  When building with support for bzlib/zlib (pcregrep) and/or readline

     (pcretest), all targets were linked against these libraries. This included

     libpcre, libpcreposix, and libpcrecpp, even though they do not use these

     libraries. This caused unwanted dependencies to be created. This problem

     has been fixed, and now only pcregrep is linked with bzlib/zlib and only

     pcretest is linked with readline.

 2.  The "typedef int BOOL" in pcre_internal.h that was included inside the

     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been

     moved outside it again, because FALSE and TRUE are already defined in AIX,

     but BOOL is not.

 3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and

     PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.

 4.  The pcregrep documentation said spaces were inserted as well as colons (or

     hyphens) following file names and line numbers when outputting matching

     lines. This is not true; no spaces are inserted. I have also clarified the

     wording for the --colour (or --color) option.

 5.  In pcregrep, when --colour was used with -o, the list of matching strings

     was not coloured; this is different to GNU grep, so I have changed it to be

     the same.

 6.  When --colo(u)r was used in pcregrep, only the first matching substring in

     each matching line was coloured. Now it goes on to look for further matches

     of any of the test patterns, which is the same behaviour as GNU grep.

 7.  A pattern that could match an empty string could cause pcregrep to loop; it

     doesn't make sense to accept an empty string match in pcregrep, so I have

     locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this

     seems to be how GNU grep behaves.

 8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at

     start or after a newline", because the conditional assertion was not being

     correctly handled. The rule now is that both the assertion and what follows

     in the first alternative must satisfy the test.

 9.  If auto-callout was enabled in a pattern with a conditional group whose

     condition was an assertion, PCRE could crash during matching, both with

     pcre_exec() and pcre_dfa_exec().

 10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was

     used for matching.

 11. Unicode property support in character classes was not working for

     characters (bytes) greater than 127 when not in UTF-8 mode.

 12. Added the -M command line option to pcretest.

 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.

 15. Added the PCRE_NO_START_OPTIMIZE match-time option.

 16. Added comments and documentation about mis-use of no_arg in the C++

     wrapper.

 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch

     from Martin Jerabek that uses macro names for all relevant character and

     string constants.

 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and

     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without

     SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of

     these, but not everybody uses configure.

 19. A conditional group that had only one branch was not being correctly

     recognized as an item that could match an empty string. This meant that an

     enclosing group might also not be so recognized, causing infinite looping

     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$

     with the subject "ab", where knowledge that the repeated group can match

     nothing is needed in order to break the loop.

 20. If a pattern that was compiled with callouts was matched using pcre_dfa_

     exec(), but without supplying a callout function, matching went wrong.

 21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory

     leak if the size of the offset vector was greater than 30. When the vector

     is smaller, the saved offsets during recursion go onto a local stack

     vector, but for larger vectors malloc() is used. It was failing to free

     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"

     error, in fact).

 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the

     heapframe that is used only when UTF-8 support is enabled. This caused no

     problem, but was untidy.

 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name

     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is

     included within another project.

 24. Steven Van Ingelgem's patches to add more options to the CMake support,

     slightly modified by me:

       (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including

           not building pcregrep.

       (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only

           if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.

 25. Forward references, both numeric and by name, in patterns that made use of

     duplicate group numbers, could behave incorrectly or give incorrect errors,

     because when scanning forward to find the reference group, PCRE was not

     taking into account the duplicate group numbers. A pattern such as

     ^X(?3)(a)(?|(b)|(q))(Y) is an example.

 26. Changed a few more instances of "const unsigned char *" to USPTR, making

     the feature of a custom pointer more persuasive (as requested by a user).

 27. Wrapped the definitions of fileno and isatty for Windows, which appear in

     pcretest.c, inside #ifndefs, because it seems they are sometimes already

     pre-defined.

 28. Added support for (*UTF8) at the start of a pattern.

 29. Arrange for flags added by the "release type" setting in CMake to be shown

     in the configuration summary.

 Version 7.8 05-Sep-08

 ---------------------

 1.  Replaced UCP searching code with optimized version as implemented for Ad

     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-

     stage table and inline lookup instead of a function, giving speed ups of 2

     to 5 times on some simple patterns that I tested. Permission was given to

     distribute the MultiStage2.py script that generates the tables (it's not in

     the tarball, but is in the Subversion repository).

 2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more

     scripts.

 3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained

     a group with a zero qualifier. The result of the study could be incorrect,

     or the function might crash, depending on the pattern.

 4.  Caseless matching was not working for non-ASCII characters in back

     references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.

     It now works when Unicode Property Support is available.

 5.  In pcretest, an escape such as \x{de} in the data was always generating

     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in

     non-UTF-8 mode. If the value is greater than 255, it gives a warning about

     truncation.

 6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).

 7.  Added two (int) casts to pcregrep when printing the difference of two

     pointers, in case they are 64-bit values.

 8.  Added comments about Mac OS X stack usage to the pcrestack man page and to

     test 2 if it fails.

 9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,

     and a #define of that name to empty if it is not externally set. This is to

     allow users of MSVC to set it if necessary.

 10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from

     the convenience functions in the pcre_get.c source file.

 11. An option change at the start of a pattern that had top-level alternatives

     could cause overwriting and/or a crash. This command provoked a crash in

     some environments:

       printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest

     This potential security problem was recorded as CVE-2008-2371.

 12. For a pattern where the match had to start at the beginning or immediately

     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and

     pcre_dfa_exec() could read past the end of the passed subject if there was

     no match. To help with detecting such bugs (e.g. with valgrind), I modified

     pcretest so that it places the subject at the end of its malloc-ed buffer.

 13. The change to pcretest in 12 above threw up a couple more cases when pcre_

     exec() might read past the end of the data buffer in UTF-8 mode.

 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and

     the data contained the byte 0x85 as part of a UTF-8 character within its

     first line. This applied both to normal and DFA matching.

 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,

     /^[^d]*?$/8 failed to match "abc".

 16. Added a missing copyright notice to pcrecpp_internal.h.

 17. Make it more clear in the documentation that values returned from

     pcre_exec() in ovector are byte offsets, not character counts.

 18. Tidied a few places to stop certain compilers from issuing warnings.

 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as

     supplied by Stefan Weber. I made a further small update for 7.8 because

     there is a change of source arrangements: the pcre_searchfuncs.c module is

     replaced by pcre_ucd.c.

 Version 7.7 07-May-08

 ---------------------

 1.  Applied Craig's patch to sort out a long long problem: "If we can't convert

     a string to a long long, pretend we don't even have a long long." This is

     done by checking for the strtoq, strtoll, and _strtoi64 functions.

 2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with

     pre-7.6 versions, which defined a global no_arg variable instead of putting

     it in the RE class. (See also #8 below.)

 3.  Remove a line of dead code, identified by coverity and reported by Nuno

     Lopes.

 4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:

     (1) The include/exclude patterns were being applied to the whole pathnames

         of files, instead of just to the final components.

     (2) If there was more than one level of directory, the subdirectories were

         skipped unless they satisfied the include/exclude conditions. This is

         inconsistent with GNU grep (and could even be seen as contrary to the

         pcregrep specification - which I improved to make it absolutely clear).

         The action now is always to scan all levels of directory, and just

         apply the include/exclude patterns to regular files.

 5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used

     --exclude_dir in the tests to avoid scanning .svn directories.

 6.  Applied Craig's patch to the QuoteMeta function so that it escapes the

     NUL character as backslash + 0 rather than backslash + NUL, because PCRE

     doesn't support NULs in patterns.

 7.  Added some missing "const"s to declarations of static tables in

     pcre_compile.c and pcre_dfa_exec.c.

 8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was

     caused by fix #2  above. (Subsequently also a second patch to fix the

     first patch. And a third patch - this was a messy problem.)

 9.  Applied Craig's patch to remove the use of push_back().

 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX

     matching function regexec().

 11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',

     which, however, unlike Perl's \g{...}, are subroutine calls, not back

     references. PCRE supports relative numbers with this syntax (I don't think

     Oniguruma does).

 12. Previously, a group with a zero repeat such as (...){0} was completely

     omitted from the compiled regex. However, this means that if the group

     was called as a subroutine from elsewhere in the pattern, things went wrong

     (an internal error was given). Such groups are now left in the compiled

     pattern, with a new opcode that causes them to be skipped at execution

     time.

 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes

     to the way PCRE behaves:

     (a) A lone ] character is dis-allowed (Perl treats it as data).

     (b) A back reference to an unmatched subpattern matches an empty string

         (Perl fails the current match path).

     (c) A data ] in a character class must be notated as \] because if the

         first data character in a class is ], it defines an empty class. (In

         Perl it is not possible to have an empty class.) The empty class []

         never matches; it forces failure and is equivalent to (*FAIL) or (?!).

         The negative empty class [^] matches any one character, independently

         of the DOTALL setting.

 14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a

     non-existent subpattern following a character class starting with ']' and

     containing () gave an internal compiling error instead of "reference to

     non-existent subpattern". Fortunately, when the pattern did exist, the

     compiled code was correct. (When scanning forwards to check for the

     existencd of the subpattern, it was treating the data ']' as terminating

     the class, so got the count wrong. When actually compiling, the reference

     was subsequently set up correctly.)

 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;

     it was being rejected as not supported by pcre_dfa_exec(), even though

     other assertions are supported. I have made pcre_dfa_exec() support

     (*FAIL).

 16. The implementation of 13c above involved the invention of a new opcode,

     OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s

     cannot be changed at match time, I realized I could make a small

     improvement to matching performance by compiling OP_ALLANY instead of

     OP_ANY for "." when DOTALL was set, and then removing the runtime tests

     on the OP_ANY path.

 17. Compiling pcretest on Windows with readline support failed without the

     following two fixes: (1) Make the unistd.h include conditional on

     HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.

 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the

     ncurses library to be included for pcretest when ReadLine support is

     requested, but also to allow for it to be overridden. This patch came from

     Daniel Bergstr�m.

 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined

     as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused

     any errors with the current Unicode tables. Thanks to Peter Kankowski for

     spotting this.

 Version 7.6 28-Jan-08

 ---------------------

 1.  A character class containing a very large number of characters with

     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer

     overflow.

 2.  Patch to cut out the "long long" test in pcrecpp_unittest when

     HAVE_LONG_LONG is not defined.

 3.  Applied Christian Ehrlicher's patch to update the CMake build files to

     bring them up to date and include new features. This patch includes:

     - Fixed PH's badly added libz and libbz2 support.

     - Fixed a problem with static linking.

     - Added pcredemo. [But later removed - see 7 below.]

     - Fixed dftables problem and added an option.

     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and

         HAVE_LONG_LONG.

     - Added readline support for pcretest.

     - Added an listing of the option settings after cmake has run.

 4.  A user submitted a patch to Makefile that makes it easy to create

     "pcre.dll" under mingw when using Configure/Make. I added stuff to

     Makefile.am that cause it to include this special target, without

     affecting anything else. Note that the same mingw target plus all

     the other distribution libraries and programs are now supported

     when configuring with CMake (see 6 below) instead of with

     Configure/Make.

 5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.

     This is an attempt to solve the reported problem "pcrecpp::no_arg is not

     exported in the Windows port". It has not yet been confirmed that the patch

     solves the problem, but it does no harm.

 6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and

     NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured

     with CMake, and also correct the comment about stack recursion.

 7.  Remove the automatic building of pcredemo from the ./configure system and

     from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example

     of a program that users should build themselves after PCRE is installed, so

     building it automatically is not really right. What is more, it gave

     trouble in some build environments.

 8.  Further tidies to CMakeLists.txt from Sheri and Christian.

 Version 7.5 10-Jan-08

 ---------------------

 1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'

     values in parens when parsing an RE using the C++ wrapper."

 2.  Negative specials like \S did not work in character classes in UTF-8 mode.

     Characters greater than 255 were excluded from the class instead of being

     included.

 3.  The same bug as (2) above applied to negated POSIX classes such as

     [:^space:].

 4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it

     defined or documented. It seems to have been a typo for PCRE_STATIC, so

     I have changed it.

 5.  The construct (?&) was not diagnosed as a syntax error (it referenced the

     first named subpattern) and a construct such as (?&a) would reference the

     first named subpattern whose name started with "a" (in other words, the

     length check was missing). Both these problems are fixed. "Subpattern name

     expected" is now given for (?&) (a zero-length name), and this patch also

     makes it give the same error for \k'' (previously it complained that that

     was a reference to a non-existent subpattern).

 6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;

     this is right because (?- can be followed by option settings as well as by

     digits. I have, however, made the messages clearer.

 7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns

     than the number used in the conditional) now cause a compile-time error.

     This is actually not compatible with Perl, which accepts such patterns, but

     treats the conditional as always being FALSE (as PCRE used to), but it

     seems to me that giving a diagnostic is better.

 8.  Change "alphameric" to the more common word "alphanumeric" in comments

     and messages.

 9.  Fix two occurrences of "backslash" in comments that should have been

     "backspace".

 10. Remove two redundant lines of code that can never be obeyed (their function

     was moved elsewhere).

 11. The program that makes PCRE's Unicode character property table had a bug

     which caused it to generate incorrect table entries for sequences of

     characters that have the same character type, but are in different scripts.

     It amalgamated them into a single range, with the script of the first of

     them. In other words, some characters were in the wrong script. There were

     thirteen such cases, affecting characters in the following ranges:

       U+002b0 - U+002c1

       U+0060c - U+0060d

       U+0061e - U+00612

       U+0064b - U+0065e

       U+0074d - U+0076d

       U+01800 - U+01805

       U+01d00 - U+01d77

       U+01d9b - U+01dbf

       U+0200b - U+0200f

       U+030fc - U+030fe

       U+03260 - U+0327f

       U+0fb46 - U+0fbb1

       U+10450 - U+1049d

 12. The -o option (show only the matching part of a line) for pcregrep was not

     compatible with GNU grep in that, if there was more than one match in a

     line, it showed only the first of them. It now behaves in the same way as

     GNU grep.

 13. If the -o and -v options were combined for pcregrep, it printed a blank

     line for every non-matching line. GNU grep prints nothing, and pcregrep now

     does the same. The return code can be used to tell if there were any

     non-matching lines.

 14. Added --file-offsets and --line-offsets to pcregrep.

 15. The pattern (?=something)(?R) was not being diagnosed as a potentially

     infinitely looping recursion. The bug was that positive lookaheads were not

     being skipped when checking for a possible empty match (negative lookaheads

     and both kinds of lookbehind were skipped).

 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the

     inclusion of <windows.h> to before rather than after the definition of

     INVALID_FILE_ATTRIBUTES (patch from David Byron).

 17. Specifying a possessive quantifier with a specific limit for a Unicode

     character property caused pcre_compile() to compile bad code, which led at

     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this

     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that

     caused the error; without that there was no problem.

 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.

 19. Added --enable-pcretest-libreadline.

 20. In pcrecpp.cc, the variable 'count' was incremented twice in

     RE::GlobalReplace(). As a result, the number of replacements returned was

     double what it should be. I removed one of the increments, but Craig sent a

     later patch that removed the other one (the right fix) and added unit tests

     that check the return values (which was not done before).

 21. Several CMake things:

     (1) Arranged that, when cmake is used on Unix, the libraries end up with

         the names libpcre and libpcreposix, not just pcre and pcreposix.

     (2) The above change means that pcretest and pcregrep are now correctly

         linked with the newly-built libraries, not previously installed ones.

     (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.

 22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*

     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a

     UTF-8 newline character). The key issue is that the pattern starts .*;

     this means that the match must be either at the beginning, or after a

     newline. The bug was in the code for advancing after a failed match and

     checking that the new position followed a newline. It was not taking

     account of UTF-8 characters correctly.

 23. PCRE was behaving differently from Perl in the way it recognized POSIX

     character classes. PCRE was not treating the sequence [:...:] as a

     character class unless the ... were all letters. Perl, however, seems to

     allow any characters between [: and :], though of course it rejects as

     unknown any "names" that contain non-letters, because all the known class

     names consist only of letters. Thus, Perl gives an error for [[:1234:]],

     for example, whereas PCRE did not - it did not recognize a POSIX character

     class. This seemed a bit dangerous, so the code has been changed to be

     closer to Perl. The behaviour is not identical to Perl, because PCRE will

     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will

     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where

     Perl does, and where it didn't before.

 24. Rewrite so as to remove the single use of %n from pcregrep because in some

     Windows environments %n is disabled by default.

 Version 7.4 21-Sep-07

 ---------------------

 1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This

     means that a class such as [\s] counted as "explicit reference to CR or

     LF". That isn't really right - the whole point of the change was to try to

     help when there was an actual mention of one of the two characters. So now

     the change happens only if \r or \n (or a literal CR or LF) character is

     encountered.

 2.  The 32-bit options word was also used for 6 internal flags, but the numbers

     of both had grown to the point where there were only 3 bits left.

     Fortunately, there was spare space in the data structure, and so I have

     moved the internal flags into a new 16-bit field to free up more option

     bits.

 3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,

     but did not set the internal JCHANGED flag - either of these is enough to

     control the way the "get" function works - but the PCRE_INFO_JCHANGED

     facility is supposed to tell if (?J) was ever used, so now (?J) at the

     start sets both bits.

 4.  Added options (at build time, compile time, exec time) to change \R from

     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.

 5.  doc/pcresyntax.html was missing from the distribution.

 6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward

     compatibility, even though it is no longer used.

 7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and

     strtoull to pcrecpp.cc to select the available functions in WIN32 when the

     windows.h file is present (where different names are used). [This was

     reversed later after testing - see 16 below.]

 8.  Changed all #include <config.h> to #include "config.h". There were also

     some further <pcre.h> cases that I changed to "pcre.h".

 9.  When pcregrep was used with the --colour option, it missed the line ending

     sequence off the lines that it output.

 10. It was pointed out to me that arrays of string pointers cause lots of

     relocations when a shared library is dynamically loaded. A technique of

     using a single long string with a table of offsets can drastically reduce

     these. I have refactored PCRE in four places to do this. The result is

     dramatic:

       Originally:                          290

       After changing UCP table:            187

       After changing error message table:   43

       After changing table of "verbs"       36

       After changing table of Posix names   22

     Thanks to the folks working on Gregex for glib for this insight.

 11. --disable-stack-for-recursion caused compiling to fail unless -enable-

     unicode-properties was also set.

 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.

 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously

     checked only for CRLF.

 14. Added casts to pcretest.c to avoid compiler warnings.

 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.

 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,

     and instead check for _strtoi64 explicitly, and avoid the use of snprintf()

     entirely. This removes changes made in 7 above.

 17. The CMake files have been updated, and there is now more information about

     building with CMake in the NON-UNIX-USE document.

 Version 7.3 28-Aug-07

 ---------------------

  1. In the rejigging of the build system that eventually resulted in 7.1, the

     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle

     brackets there is not right, since it causes compilers to look for an

     installed pcre.h, not the version that is in the source that is being

     compiled (which of course may be different). I have changed it back to:

       #include "pcre.h"

     I have a vague recollection that the change was concerned with compiling in

     different directories, but in the new build system, that is taken care of

     by the VPATH setting the Makefile.

  2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed

     when the subject happened to end in the byte 0x85 (e.g. if the last

     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline

     characters but of course it shouldn't be taken as a newline when it is part

     of another character. The bug was that, for an unlimited repeat of . in

     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by

     characters when looking for a newline.

  3. A small performance improvement in the DOTALL UTF-8 mode .* case.

  4. Debugging: adjusted the names of opcodes for different kinds of parentheses

     in debug output.

  5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for

     long printing in the pcrecpp unittest when running under MinGW.

  6. ESC_K was left out of the EBCDIC table.

  7. Change 7.0/38 introduced a new limit on the number of nested non-capturing

     parentheses; I made it 1000, which seemed large enough. Unfortunately, the

     limit also applies to "virtual nesting" when a pattern is recursive, and in

     this case 1000 isn't so big. I have been able to remove this limit at the

     expense of backing off one optimization in certain circumstances. Normally,

     when pcre_exec() would call its internal match() function recursively and

     immediately return the result unconditionally, it uses a "tail recursion"

     feature to save stack. However, when a subpattern that can match an empty

     string has an unlimited repetition quantifier, it no longer makes this

     optimization. That gives it a stack frame in which to save the data for

     checking that an empty string has been matched. Previously this was taken

     from the 1000-entry workspace that had been reserved. So now there is no

     explicit limit, but more stack is used.

  8. Applied Daniel's patches to solve problems with the import/export magic

     syntax that is required for Windows, and which was going wrong for the

     pcreposix and pcrecpp parts of the library. These were overlooked when this

     problem was solved for the main library.

  9. There were some crude static tests to avoid integer overflow when computing

     the size of patterns that contain repeated groups with explicit upper

     limits. As the maximum quantifier is 65535, the maximum group length was

     set at 30,000 so that the product of these two numbers did not overflow a

     32-bit integer. However, it turns out that people want to use groups that

     are longer than 30,000 bytes (though not repeat them that many times).

     Change 7.0/17 (the refactoring of the way the pattern size is computed) has

     made it possible to implement the integer overflow checks in a much more

     dynamic way, which I have now done. The artificial limitation on group

     length has been removed - we now have only the limit on the total length of

     the compiled pattern, which depends on the LINK_SIZE setting.

 10. Fixed a bug in the documentation for get/copy named substring when

     duplicate names are permitted. If none of the named substrings are set, the

     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an

     empty string.

 11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E

     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,

     because the ] is interpreted as the first data character and the

     terminating ] is not found. PCRE has been made compatible with Perl in this

     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could

     cause memory overwriting.

 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty

     string has been matched (to stop an infinite loop). It was not recognizing

     a conditional subpattern that could match an empty string if that

     subpattern was within another subpattern. For example, it looped when

     trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the

     condition was not nested. This bug has been fixed.

 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack

     past the start of the subject in the presence of bytes with the top bit

     set, for example "\x8aBCD".

 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),

     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).

 14. Optimized (?!) to (*FAIL).

 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.

     This restricts code points to be within the range 0 to 0x10FFFF, excluding

     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the

     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still

     does: it's just the validity check that is more restrictive.

 16. Inserted checks for integer overflows during escape sequence (backslash)

     processing, and also fixed erroneous offset values for syntax errors during

     backslash processing.

 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)

     for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".

 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"

     caused an overrun.

 19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with

     something other than just ASCII characters) inside a group that had an

     unlimited repeat caused a loop at compile time (while checking to see

     whether the group could match an empty string).

 20. Debugging a pattern containing \p or \P could cause a crash. For example,

     [\P{Any}] did so. (Error in the code for printing property names.)

 21. An orphan \E inside a character class could cause a crash.

 22. A repeated capturing bracket such as (A)? could cause a wild memory

     reference during compilation.

 23. There are several functions in pcre_compile() that scan along a compiled

     expression for various reasons (e.g. to see if it's fixed length for look

     behind). There were bugs in these functions when a repeated \p or \P was

     present in the pattern. These operators have additional parameters compared

     with \d, etc, and these were not being taken into account when moving along

     the compiled data. Specifically:

     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed

         length.

     (b) An item such as \pL+ within a repeated group could cause crashes or

         loops.

     (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect

         "reference to non-existent subpattern" error.

     (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.

 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte

     characters were involved (for example /\S{2}/8g with "A\x{a3}BC").

 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.

 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other

     character were causing crashes (broken optimization).

 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing

     \p or \P) caused a compile-time loop.

 28. More problems have arisen in unanchored patterns when CRLF is a valid line

     break. For example, the unstudied pattern [\r\n]A does not match the string

     "\r\nA" because change 7.0/46 below moves the current point on by two

     characters after failing to match at the start. However, the pattern \nA

     *does* match, because it doesn't start till \n, and if [\r\n]A is studied,

     the same is true. There doesn't seem any very clean way out of this, but

     what I have chosen to do makes the common cases work: PCRE now takes note

     of whether there can be an explicit match for \r or \n anywhere in the

     pattern, and if so, 7.0/46 no longer applies. As part of this change,

     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled

     pattern has explicit CR or LF references.

 29. Added (*CR) etc for changing newline setting at start of pattern.

 Version 7.2 19-Jun-07

 ---------------------

  1. If the fr_FR locale cannot be found for test 3, try the "french" locale,

     which is apparently normally available under Windows.

  2. Re-jig the pcregrep tests with different newline settings in an attempt

     to make them independent of the local environment's newline setting.

  3. Add code to configure.ac to remove -g from the CFLAGS default settings.

  4. Some of the "internals" tests were previously cut out when the link size

     was not 2, because the output contained actual offsets. The recent new

     "Z" feature of pcretest means that these can be cut out, making the tests

     usable with all link sizes.

  5. Implemented Stan Switzer's goto replacement for longjmp() when not using

     stack recursion. This gives a massive performance boost under BSD, but just

     a small improvement under Linux. However, it saves one field in the frame

     in all cases.

  6. Added more features from the forthcoming Perl 5.10:

     (a) (?-n) (where n is a string of digits) is a relative subroutine or

         recursion call. It refers to the nth most recently opened parentheses.

     (b) (?+n) is also a relative subroutine call; it refers to the nth next

         to be opened parentheses.

     (c) Conditions that refer to capturing parentheses can be specified

         relatively, for example, (?(-2)... or (?(+3)...

     (d) \K resets the start of the current match so that everything before

         is not part of it.

     (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).

     (f) \g{name} is another synonym - part of Perl 5.10's unification of

         reference syntax.

     (g) (?| introduces a group in which the numbering of parentheses in each

         alternative starts with the same number.

     (h) \h, \H, \v, and \V match horizontal and vertical whitespace.

  7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and

     PCRE_INFO_JCHANGED.

  8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not

     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code

     for detecting groups that can match an empty string.

  9. A pattern with a very large number of alternatives (more than several

     hundred) was running out of internal workspace during the pre-compile

     phase, where pcre_compile() figures out how much memory will be needed. A

     bit of new cunning has reduced the workspace needed for groups with

     alternatives. The 1000-alternative test pattern now uses 12 bytes of

     workspace instead of running out of the 4096 that are available.

 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.

 11. Applied patch from Google to remove an optimization that didn't quite work.

     The report of the bug said:

       pcrecpp::RE("a*").FullMatch("aaa") matches, while

       pcrecpp::RE("a*?").FullMatch("aaa") does not, and

       pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.

 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127

     it matched the wrong number of bytes.

 Version 7.1 24-Apr-07

 ---------------------

  1. Applied Bob Rossi and Daniel G's patches to convert the build system to one

     that is more "standard", making use of automake and other Autotools. There

     is some re-arrangement of the files and adjustment of comments consequent

     on this.

  2. Part of the patch fixed a problem with the pcregrep tests. The test of -r

     for recursive directory scanning broke on some systems because the files

     are not scanned in any specific order and on different systems the order

     was different. A call to "sort" has been inserted into RunGrepTest for the

     approprate test as a short-term fix. In the longer term there may be an

     alternative.

  3. I had an email from Eric Raymond about problems translating some of PCRE's

     man pages to HTML (despite the fact that I distribute HTML pages, some

     people do their own conversions for various reasons). The problems

     concerned the use of low-level troff macros .br and .in. I have therefore

     removed all such uses from the man pages (some were redundant, some could

     be replaced by .nf/.fi pairs). The 132html script that I use to generate

     HTML has been updated to handle .nf/.fi and to complain if it encounters

     .br or .in.

  4. Updated comments in configure.ac that get placed in config.h.in and also

     arranged for config.h to be included in the distribution, with the name

     config.h.generic, for the benefit of those who have to compile without

     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).

  5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan

     Weber: (1) pcre_internal.h was missing some function renames; (2) updated

     makevp.bat for the current PCRE, using the additional files

     makevp_c.txt, makevp_l.txt, and pcregexp.pas.

  6. A Windows user reported a minor discrepancy with test 2, which turned out

     to be caused by a trailing space on an input line that had got lost in his

     copy. The trailing space was an accident, so I've just removed it.

  7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told

     that is needed.

  8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)

     as "const" (a) because they are and (b) because it helps the PHP

     maintainers who have recently made a script to detect big data structures

     in the php code that should be moved to the .rodata section. I remembered

     to update Builducptable as well, so it won't revert if ucptable.h is ever

     re-created.

  9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,

     pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in

     order to be able to cut out the UTF-8 tables in the latter when UTF-8

     support is not required. This saves 1.5-2K of code, which is important in

     some applications.

     Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c

     so as not to refer to the tables, even though these functions will never be

     called when UTF-8 support is disabled. Otherwise there are problems with a

     shared library.

 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:

     (a) It was defining its arguments as char * instead of void *.

     (b) It was assuming that all moves were upwards in memory; this was true

         a long time ago when I wrote it, but is no longer the case.

     The emulated memove() is provided for those environments that have neither

     memmove() nor bcopy(). I didn't think anyone used it these days, but that

     is clearly not the case, as these two bugs were recently reported.

 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,

     and Detrail to create the HTML documentation, the .txt form of the man

     pages, and it removes trailing spaces from listed files. It also creates

     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter

     case, it wraps all the #defines with #ifndefs. This script should be run

     before "make dist".

 12. Fixed two fairly obscure bugs concerned with quantified caseless matching

     with Unicode property support.

     (a) For a maximizing quantifier, if the two different cases of the

         character were of different lengths in their UTF-8 codings (there are

         some cases like this - I found 11), and the matching function had to

         back up over a mixture of the two cases, it incorrectly assumed they

         were both the same length.

     (b) When PCRE was configured to use the heap rather than the stack for

         recursion during matching, it was not correctly preserving the data for

         the other case of a UTF-8 character when checking ahead for a match

         while processing a minimizing repeat. If the check also involved

         matching a wide character, but failed, corruption could cause an

         erroneous result when trying to check for a repeat of the original

         character.

 13. Some tidying changes to the testing mechanism:

     (a) The RunTest script now detects the internal link size and whether there

         is UTF-8 and UCP support by running ./pcretest -C instead of relying on

         values substituted by "configure". (The RunGrepTest script already did

         this for UTF-8.) The configure.ac script no longer substitutes the

         relevant variables.

     (b) The debugging options /B and /D in pcretest show the compiled bytecode

         with length and offset values. This means that the output is different

         for different internal link sizes. Test 2 is skipped for link sizes

         other than 2 because of this, bypassing the problem. Unfortunately,

         there was also a test in test 3 (the locale tests) that used /B and

         failed for link sizes other than 2. Rather than cut the whole test out,

         I have added a new /Z option to pcretest that replaces the length and

         offset values with spaces. This is now used to make test 3 independent

         of link size. (Test 2 will be tidied up later.)

 14. If erroroffset was passed as NULL to pcre_compile, it provoked a

     segmentation fault instead of returning the appropriate error message.

 15. In multiline mode when the newline sequence was set to "any", the pattern

     ^$ would give a match between the \r and \n of a subject such as "A\r\nB".

     This doesn't seem right; it now treats the CRLF combination as the line

     ending, and so does not match in that case. It's only a pattern such as ^$

     that would hit this one: something like ^ABC$ would have failed after \r

     and then tried again after \r\n.

 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"

     in an attempt to make files that differ only in their line terminators

     compare equal. This works on Linux.

 17. Under certain error circumstances pcregrep might try to free random memory

     as it exited. This is now fixed, thanks to valgrind.

 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string

     "abc\r\n\r\n", it found an unwanted second match after the second \r. This

     was because its rules for how to advance for /g after matching an empty

     string at the end of a line did not allow for this case. They now check for

     it specially.

 20. pcretest is supposed to handle patterns and data of any length, by

     extending its buffers when necessary. It was getting this wrong when the

     buffer for a data line had to be extended.

 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or

     CRLF as a newline sequence.

 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut

     out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but

     I have nevertheless tidied it up.

 23. Added some casts to kill warnings from HP-UX ia64 compiler.

 24. Added a man page for pcre-config.

 Version 7.0 19-Dec-06

 ---------------------

  1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by

     moving to gcc 4.1.1.

  2. The -S option for pcretest uses setrlimit(); I had omitted to #include

     sys/time.h, which is documented as needed for this function. It doesn't

     seem to matter on Linux, but it showed up on some releases of OS X.

  3. It seems that there are systems where bytes whose values are greater than

     127 match isprint() in the "C" locale. The "C" locale should be the

     default when a C program starts up. In most systems, only ASCII printing

     characters match isprint(). This difference caused the output from pcretest

     to vary, making some of the tests fail. I have changed pcretest so that:

     (a) When it is outputting text in the compiled version of a pattern, bytes

         other than 32-126 are always shown as hex escapes.

     (b) When it is outputting text that is a matched part of a subject string,

         it does the same, unless a different locale has been set for the match

         (using the /L modifier). In this case, it uses isprint() to decide.

  4. Fixed a major bug that caused incorrect computation of the amount of memory

     required for a compiled pattern when options that changed within the

     pattern affected the logic of the preliminary scan that determines the

     length. The relevant options are -x, and -i in UTF-8 mode. The result was

     that the computed length was too small. The symptoms of this bug were

     either the PCRE error "internal error: code overflow" from pcre_compile(),

     or a glibc crash with a message such as "pcretest: free(): invalid next

     size (fast)". Examples of patterns that provoked this bug (shown in

     pcretest format) are:

       /(?-x: )/x

       /(?x)(?-x: \s*#\s*)/

       /((?i)[\x{c0}])/8

       /(?i:[\x{c0}])/8

     HOWEVER: Change 17 below makes this fix obsolete as the memory computation

     is now done differently.

  5. Applied patches from Google to: (a) add a QuoteMeta function to the C++

     wrapper classes; (b) implement a new function in the C++ scanner that is

     more efficient than the old way of doing things because it avoids levels of

     recursion in the regex matching; (c) add a paragraph to the documentation

     for the FullMatch() function.

  6. The escape sequence \n was being treated as whatever was defined as

     "newline". Not only was this contrary to the documentation, which states

     that \n is character 10 (hex 0A), but it also went horribly wrong when

     "newline" was defined as CRLF. This has been fixed.

  7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)

     was being set to -1 for the "end of line" case (supposedly a value that no

     character can have). Though this value is never used (the check for end of

     line is "zero bytes in current character"), it caused compiler complaints.

     I've changed it to 0xffffffff.

  8. In pcre_version.c, the version string was being built by a sequence of

     C macros that, in the event of PCRE_PRERELEASE being defined as an empty

     string (as it is for production releases) called a macro with an empty

     argument. The C standard says the result of this is undefined. The gcc

     compiler treats it as an empty string (which was what was wanted) but it is

     reported that Visual C gives an error. The source has been hacked around to

     avoid this problem.

  9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows

     builds of pcretest, and changed the call to _setmode() to use _O_BINARY

     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all

     of them did).

 10. Originally, pcretest opened its input and output without "b"; then I was

     told that "b" was needed in some environments, so it was added for release

     5.0 to both the input and output. (It makes no difference on Unix-like

     systems.) Later I was told that it is wrong for the input on Windows. I've

     now abstracted the modes into two macros, to make it easier to fiddle with

     them, and removed "b" from the input mode under Windows.

 11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.

 12. Added -help and --help to pcretest as an official way of being reminded

     of the options.

 13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in

     and pcrecpp.cc because they annoy compilers at high warning levels.

 14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.

 15. Fixed an occurrence of == in configure.ac that should have been = (shell

     scripts are not C programs :-) and which was not noticed because it works

     on Linux.

 16. pcretest is supposed to handle any length of pattern and data line (as one

     line or as a continued sequence of lines) by extending its input buffer if

     necessary. This feature was broken for very long pattern lines, leading to

     a string of junk being passed to pcre_compile() if the pattern was longer

     than about 50K.

 17. I have done a major re-factoring of the way pcre_compile() computes the

     amount of memory needed for a compiled pattern. Previously, there was code

     that made a preliminary scan of the pattern in order to do this. That was

     OK when PCRE was new, but as the facilities have expanded, it has become

     harder and harder to keep it in step with the real compile phase, and there

     have been a number of bugs (see for example, 4 above). I have now found a

     cunning way of running the real compile function in a "fake" mode that

     enables it to compute how much memory it would need, while actually only

     ever using a few hundred bytes of working memory and without too many

     tests of the mode. This should make future maintenance and development

     easier. A side effect of this work is that the limit of 200 on the nesting

     depth of parentheses has been removed (though this was never a serious

     limitation, I suspect). However, there is a downside: pcre_compile() now

     runs more slowly than before (30% or more, depending on the pattern). I

     hope this isn't a big issue. There is no effect on runtime performance.

 18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a

     newline (only possible for the last line of a file) and it was a

     pattern that set a locale (followed by /Lsomething), pcretest crashed.

 19. Added additional timing features to pcretest. (1) The -tm option now times

     matching only, not compiling. (2) Both -t and -tm can be followed, as a

     separate command line item, by a number that specifies the number of

     repeats to use when timing. The default is 50000; this gives better

     precision, but takes uncomfortably long for very large patterns.

 20. Extended pcre_study() to be more clever in cases where a branch of a

     subpattern has no definite first character. For example, (a*|b*)[cd] would

     previously give no result from pcre_study(). Now it recognizes that the

     first character must be a, b, c, or d.

 21. There was an incorrect error "recursive call could loop indefinitely" if

     a subpattern (or the entire pattern) that was being tested for matching an

     empty string contained only one non-empty item after a nested subpattern.

     For example, the pattern (?>\x{100}*)\d(?R) provoked this error

     incorrectly, because the \d was being skipped in the check.

 22. The pcretest program now has a new pattern option /B and a command line

     option -b, which is equivalent to adding /B to every pattern. This causes

     it to show the compiled bytecode, without the additional information that

     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D

     is the same as /B/I).

 23. A new optimization is now able automatically to treat some sequences such

     as a*b as a*+b. More specifically, if something simple (such as a character

     or a simple class like \d) has an unlimited quantifier, and is followed by

     something that cannot possibly match the quantified thing, the quantifier

     is automatically "possessified".

 24. A recursive reference to a subpattern whose number was greater than 39

     went wrong under certain circumstances in UTF-8 mode. This bug could also

     have affected the operation of pcre_study().

 25. Realized that a little bit of performance could be had by replacing

     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.

 26. Timing data from pcretest is now shown to 4 decimal places instead of 3.

 27. Possessive quantifiers such as a++ were previously implemented by turning

     them into atomic groups such as ($>a+). Now they have their own opcodes,

     which improves performance. This includes the automatically created ones

     from 23 above.

 28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a

     lookahead was broken if it was not anchored. PCRE was mistakenly expecting

     the first matched character to be a colon. This applied both to named and

     numbered groups.

 29. The ucpinternal.h header file was missing its idempotency #ifdef.

 30. I was sent a "project" file called libpcre.a.dev which I understand makes

     building PCRE on Windows easier, so I have included it in the distribution.

 31. There is now a check in pcretest against a ridiculously large number being

     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G

     loop, the loop is abandoned.

 32. Forward references to subpatterns in conditions such as (?(2)...) where

     subpattern 2 is defined later cause pcre_compile() to search forwards in

     the pattern for the relevant set of parentheses. This search went wrong

     when there were unescaped parentheses in a character class, parentheses

     escaped with \Q...\E, or parentheses in a #-comment in /x mode.

 33. "Subroutine" calls and backreferences were previously restricted to

     referencing subpatterns earlier in the regex. This restriction has now

     been removed.

 34. Added a number of extra features that are going to be in Perl 5.10. On the

     whole, these are just syntactic alternatives for features that PCRE had

     previously implemented using the Python syntax or my own invention. The

     other formats are all retained for compatibility.

     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well

         as (?P<name>...). The new forms, as well as being in Perl 5.10, are

         also .NET compatible.

     (b) A recursion or subroutine call to a named group can now be defined as

         (?&name) as well as (?P>name).

     (c) A backreference to a named group can now be defined as \k<name> or

         \k'name' as well as (?P=name). The new forms, as well as being in Perl

         5.10, are also .NET compatible.

     (d) A conditional reference to a named group can now use the syntax

         (?(<name>) or (?('name') as well as (?(name).

     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define

         groups (named and numbered) that are never evaluated inline, but can be

         called as "subroutines" from elsewhere. In effect, the DEFINE condition

         is always false. There may be only one alternative in such a group.

     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well

         as the simple (?(R). The condition is true only if the most recent

         recursion is that of the given number or name. It does not search out

         through the entire recursion stack.

     (g) The escape \gN or \g{N} has been added, where N is a positive or

         negative number, specifying an absolute or relative reference.

 35. Tidied to get rid of some further signed/unsigned compiler warnings and

     some "unreachable code" warnings.

 36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other

     things, this adds five new scripts.

 37. Perl ignores orphaned \E escapes completely. PCRE now does the same.

     There were also incompatibilities regarding the handling of \Q..\E inside

     character classes, for example with patterns like [\Qa\E-\Qz\E] where the

     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.

 38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group

     matches an empty string, and forcibly breaks the loop. There were bugs in

     this code in non-simple cases. For a pattern such as  ^(a()*)*  matched

     against  aaaa  the result was just "a" rather than "aaaa", for example. Two

     separate and independent bugs (that affected different cases) have been

     fixed.

 39. Refactored the code to abolish the use of different opcodes for small

     capturing bracket numbers. This is a tidy that I avoided doing when I

     removed the limit on the number of capturing brackets for 3.5 back in 2001.

     The new approach is not only tidier, it makes it possible to reduce the

     memory needed to fix the previous bug (38).

 40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline

     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when

     processing dot, circumflex, or dollar metacharacters, or #-comments in /x

     mode.

 41. Add \R to match any Unicode newline sequence, as suggested in the Unicode

     report.

 42. Applied patch, originally from Ari Pollak, modified by Google, to allow

     copy construction and assignment in the C++ wrapper.

 43. Updated pcregrep to support "--newline=any". In the process, I fixed a

     couple of bugs that could have given wrong results in the "--newline=crlf"

     case.

 44. Added a number of casts and did some reorganization of signed/unsigned int

     variables following suggestions from Dair Grant. Also renamed the variable

     "this" as "item" because it is a C++ keyword.

 45. Arranged for dftables to add

       #include "pcre_internal.h"

     to pcre_chartables.c because without it, gcc 4.x may remove the array

     definition from the final binary if PCRE is built into a static library and

     dead code stripping is activated.

 46. For an unanchored pattern, if a match attempt fails at the start of a

     newline sequence, and the newline setting is CRLF or ANY, and the next two

     characters are CRLF, advance by two characters instead of one.

 Version 6.7 04-Jul-06

 ---------------------

  1. In order to handle tests when input lines are enormously long, pcretest has

     been re-factored so that it automatically extends its buffers when

     necessary. The code is crude, but this _is_ just a test program. The

     default size has been increased from 32K to 50K.

  2. The code in pcre_study() was using the value of the re argument before

     testing it for NULL. (Of course, in any sensible call of the function, it

     won't be NULL.)

  3. The memmove() emulation function in pcre_internal.h, which is used on

     systems that lack both memmove() and bcopy() - that is, hardly ever -

     was missing a "static" storage class specifier.

  4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns

     containing an extended class (one that cannot be represented by a bitmap

     because it contains high-valued characters or Unicode property items, e.g.

     [\pZ]). Almost always one would set UTF-8 mode when processing such a

     pattern, but PCRE should not loop if you do not (it no longer does).

     [Detail: two cases were found: (a) a repeated subpattern containing an

     extended class; (b) a recursive reference to a subpattern that followed a

     previous extended class. It wasn't skipping over the extended class

     correctly when UTF-8 mode was not set.]

  5. A negated single-character class was not being recognized as fixed-length

     in lookbehind assertions such as (?<=[^f]), leading to an incorrect

     compile error "lookbehind assertion is not fixed length".

  6. The RunPerlTest auxiliary script was showing an unexpected difference

     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to

     write a Perl script that can interpret lines of an input file either as

     byte characters or as UTF-8, which is what "perltest" was being required to

     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you

     can't do is switch easily at run time between having the "use utf8;" pragma

     or not. In the end, I fudged it by using the RunPerlTest script to insert

     "use utf8;" explicitly for the UTF-8 tests.

  7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at

     the end of the subject string, contrary to the documentation and to what

     Perl does. This was true of both matching functions. Now it matches only at

     the start of the subject and immediately after *internal* newlines.

  8. A call of pcre_fullinfo() from pcretest to get the option bits was passing

     a pointer to an int instead of a pointer to an unsigned long int. This

     caused problems on 64-bit systems.

  9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another

     instance of the 'standard' template library not being so standard".

 10. There was no check on the number of named subpatterns nor the maximum

     length of a subpattern name. The product of these values is used to compute

     the size of the memory block for a compiled pattern. By supplying a very

     long subpattern name and a large number of named subpatterns, the size

     computation could be caused to overflow. This is now prevented by limiting

     the length of names to 32 characters, and the number of named subpatterns

     to 10,000.

 11. Subpatterns that are repeated with specific counts have to be replicated in

     the compiled pattern. The size of memory for this was computed from the

     length of the subpattern and the repeat count. The latter is limited to

     65535, but there was no limit on the former, meaning that integer overflow

     could in principle occur. The compiled length of a repeated subpattern is

     now limited to 30,000 bytes in order to prevent this.

 12. Added the optional facility to have named substrings with the same name.

 13. Added the ability to use a named substring as a condition, using the

     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that

     are numbers (not recommended). Forward references are permitted.

 14. Added forward references in named backreferences (if you see what I mean).

 15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the

     pattern could run off the end of the subject. For example, the pattern

     "(?s)(.{1,5})"8 did this with the subject "ab".

 16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if

     PCRE_CASELESS was set when matching characters that were quantified with ?

     or *.

 17. A character class other than a single negated character that had a minimum

     but no maximum quantifier - for example [ab]{6,} - was not handled

     correctly by pce_dfa_exec(). It would match only one character.

 18. A valid (though odd) pattern that looked like a POSIX character

     class but used an invalid character after [ (for example [[,abc,]]) caused

     pcre_compile() to give the error "Failed: internal error: code overflow" or

     in some cases to crash with a glibc free() error. This could even happen if

     the pattern terminated after [[ but there just happened to be a sequence of

     letters, a binary zero, and a closing ] in the memory that followed.

 19. Perl's treatment of octal escapes in the range \400 to \777 has changed

     over the years. Originally (before any Unicode support), just the bottom 8

     bits were taken. Thus, for example, \500 really meant \100. Nowadays the

     output from "man perlunicode" includes this:

       The regular expression compiler produces polymorphic opcodes.  That

       is, the pattern adapts to the data and automatically switches to

       the Unicode character scheme when presented with Unicode data--or

       instead uses a traditional byte scheme when presented with byte

       data.

     Sadly, a wide octal escape does not cause a switch, and in a string with

     no other multibyte characters, these octal escapes are treated as before.

     Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern

     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a

     Unicode string.

     I have not perpetrated such confusion in PCRE. Up till now, it took just

     the bottom 8 bits, as in old Perl. I have now made octal escapes with

     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they

     translate to the appropriate multibyte character.

 29. Applied some refactoring to reduce the number of warnings from Microsoft

     and Borland compilers. This has included removing the fudge introduced

     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused

     a warning about an unused variable.

 21. PCRE has not included VT (character 0x0b) in the set of whitespace

     characters since release 4.0, because Perl (from release 5.004) does not.

     [Or at least, is documented not to: some releases seem to be in conflict

     with the documentation.] However, when a pattern was studied with

     pcre_study() and all its branches started with \s, PCRE still included VT

     as a possible starting character. Of course, this did no harm; it just

     caused an unnecessary match attempt.

 22. Removed a now-redundant internal flag bit that recorded the fact that case

     dependency changed within the pattern. This was once needed for "required

     byte" processing, but is no longer used. This recovers a now-scarce options

     bit. Also moved the least significant internal flag bit to the most-

     significant bit of the word, which was not previously used (hangover from

     the days when it was an int rather than a uint) to free up another bit for

     the future.

 23. Added support for CRLF line endings as well as CR and LF. As well as the

     default being selectable at build time, it can now be changed at runtime

     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to

     specify that it is scanning data with non-default line endings.

 24. Changed the definition of CXXLINK to make it agree with the definition of

     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.

 25. Applied Ian Taylor's patches to avoid using another stack frame for tail

     recursions. This makes a big different to stack usage for some patterns.

 26. If a subpattern containing a named recursion or subroutine reference such

     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of

     the space required for the compiled pattern went wrong and gave too small a

     value. Depending on the environment, this could lead to "Failed: internal

     error: code overflow at offset 49" or "glibc detected double free or

     corruption" errors.

 27. Applied patches from Google (a) to support the new newline modes and (b) to

     advance over multibyte UTF-8 characters in GlobalReplace.

 28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a

     difference for some implementation of PCRE in some Windows version.

 29. Added some extra testing facilities to pcretest:

     \q<number>   in a data line sets the "match limit" value

     \Q<number>   in a data line sets the "match recursion limt" value

     -S <number>  sets the stack size, where <number> is in megabytes

     The -S option isn't available for Windows.

 Version 6.6 06-Feb-06

 ---------------------

  1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined

     in pcreposix.h. I have copied the definition from pcre.h.

  2. Change 25 for 6.5 broke compilation in a build directory out-of-tree

     because pcre.h is no longer a built file.

  3. Added Jeff Friedl's additional debugging patches to pcregrep. These are

     not normally included in the compiled code.

 Version 6.5 01-Feb-06

 ---------------------

  1. When using the partial match feature with pcre_dfa_exec(), it was not

     anchoring the second and subsequent partial matches at the new starting

     point. This could lead to incorrect results. For example, with the pattern

     /1234/, partially matching against "123" and then "a4" gave a match.

  2. Changes to pcregrep:

     (a) All non-match returns from pcre_exec() were being treated as failures

         to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an

         error message is output. Some extra information is given for the

         PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are

         probably the only errors that are likely to be caused by users (by

         specifying a regex that has nested indefinite repeats, for instance).

         If there are more than 20 of these errors, pcregrep is abandoned.

     (b) A binary zero was treated as data while matching, but terminated the

         output line if it was written out. This has been fixed: binary zeroes

         are now no different to any other data bytes.

     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is

         used to set a locale for matching. The --locale=xxxx long option has

         been added (no short equivalent) to specify a locale explicitly on the

         pcregrep command, overriding the environment variables.

     (d) When -B was used with -n, some line numbers in the output were one less

         than they should have been.

     (e) Added the -o (--only-matching) option.

     (f) If -A or -C was used with -c (count only), some lines of context were

         accidentally printed for the final match.

     (g) Added the -H (--with-filename) option.

     (h) The combination of options -rh failed to suppress file names for files

         that were found from directory arguments.

     (i) Added the -D (--devices) and -d (--directories) options.

     (j) Added the -F (--fixed-strings) option.

     (k) Allow "-" to be used as a file name for -f as well as for a data file.

     (l) Added the --colo(u)r option.

     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it

         is not present by default.

  3. A nasty bug was discovered in the handling of recursive patterns, that is,

     items such as (?R) or (?1), when the recursion could match a number of

     alternatives. If it matched one of the alternatives, but subsequently,

     outside the recursion, there was a failure, the code tried to back up into

     the recursion. However, because of the way PCRE is implemented, this is not

     possible, and the result was an incorrect result from the match.

     In order to prevent this happening, the specification of recursion has

     been changed so that all such subpatterns are automatically treated as

     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).

  4. I had overlooked the fact that, in some locales, there are characters for

     which isalpha() is true but neither isupper() nor islower() are true. In

     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine

     and ordfeminine) are like this. This affected the treatment of \w and \W

     when they appeared in character classes, but not when they appeared outside

     a character class. The bit map for "word" characters is now created

     separately from the results of isalnum() instead of just taking it from the

     upper, lower, and digit maps. (Plus the underscore character, of course.)

  5. The above bug also affected the handling of POSIX character classes such as

     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's

     permanent tables. Instead, the bit maps for such a class were previously

     created as the appropriate unions of the upper, lower, and digit bitmaps.

     Now they are created by subtraction from the [[:word:]] class, which has

     its own bitmap.

  6. The [[:blank:]] character class matches horizontal, but not vertical space.

     It is created by subtracting the vertical space characters (\x09, \x0a,

     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the

     subtraction was done in the overall bitmap for a character class, meaning

     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not

     be recognized. This bug has been fixed.

  7. Patches from the folks at Google:

       (a) pcrecpp.cc: "to handle a corner case that may or may not happen in

       real life, but is still worth protecting against".

       (b) pcrecpp.cc: "corrects a bug when negative radixes are used with

       regular expressions".

       (c) pcre_scanner.cc: avoid use of std::count() because not all systems

       have it.

       (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by

       "configure" and the latter not, in order to fix a problem somebody had

       with compiling the Arg class on HP-UX.

       (e) Improve the error-handling of the C++ wrapper a little bit.

       (f) New tests for checking recursion limiting.

  8. The pcre_memmove() function, which is used only if the environment does not

     have a standard memmove() function (and is therefore rarely compiled),

     contained two bugs: (a) use of int instead of size_t, and (b) it was not

     returning a result (though PCRE never actually uses the result).

  9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously

     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is

     returned instead of calling malloc() with an overflowing number that would

     most likely cause subsequent chaos.

 10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.

 11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled

     with this option is matched, the nmatch and pmatch options of regexec() are

     ignored.

 12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is

     provided in case anyone wants to the the POSIX interface with UTF-8

     strings.

 13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the

     C++ linking (needed for some HP-UX environments).

 14. Avoid compiler warnings in get_ucpname() when compiled without UCP support

     (unused parameter) and in the pcre_printint() function (omitted "default"

     switch label when the default is to do nothing).

 15. Added some code to make it possible, when PCRE is compiled as a C++

     library, to replace subject pointers for pcre_exec() with a smart pointer

     class, thus making it possible to process discontinuous strings.

 16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform

     much the same function. They were added by different people who were trying

     to make PCRE easy to compile on non-Unix systems. It has been suggested

     that PCRE_EXPORT be abolished now that there is more automatic apparatus

     for compiling on Windows systems. I have therefore replaced it with

     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it

     defaults to "extern" for C or "extern C" for C++, which works fine on

     Unix-like systems. It is now possible to override the value of PCRE_DATA_

     SCOPE with something explicit in config.h. In addition:

     (a) pcreposix.h still had just "extern" instead of either of these macros;

         I have replaced it with PCRE_DATA_SCOPE.

     (b) Functions such as _pcre_xclass(), which are internal to the library,

         but external in the C sense, all had PCRE_EXPORT in their definitions.

         This is apparently wrong for the Windows case, so I have removed it.

         (It makes no difference on Unix-like systems.)

 17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting

     of recursive calls to match(). This is different to MATCH_LIMIT because

     that limits the total number of calls to match(), not all of which increase

     the depth of recursion. Limiting the recursion depth limits the amount of

     stack (or heap if NO_RECURSE is set) that is used. The default can be set

     when PCRE is compiled, and changed at run time. A patch from Google adds

     this functionality to the C++ interface.

 18. Changes to the handling of Unicode character properties:

     (a) Updated the table to Unicode 4.1.0.

     (b) Recognize characters that are not in the table as "Cn" (undefined).

     (c) I revised the way the table is implemented to a much improved format

         which includes recognition of ranges. It now supports the ranges that

         are defined in UnicodeData.txt, and it also amalgamates other

         characters into ranges. This has reduced the number of entries in the

         table from around 16,000 to around 3,000, thus reducing its size

         considerably. I realized I did not need to use a tree structure after

         all - a binary chop search is just as efficient. Having reduced the

         number of entries, I extended their size from 6 bytes to 8 bytes to

         allow for more data.

     (d) Added support for Unicode script names via properties such as \p{Han}.

 19. In UTF-8 mode, a backslash followed by a non-Ascii character was not

     matching that character.

 20. When matching a repeated Unicode property with a minimum greater than zero,

     (for example \pL{2,}), PCRE could look past the end of the subject if it

     reached it while seeking the minimum number of characters. This could

     happen only if some of the characters were more than one byte long, because

     there is a check for at least the minimum number of bytes.

 21. Refactored the implementation of \p and \P so as to be more general, to

     allow for more different types of property in future. This has changed the

     compiled form incompatibly. Anybody with saved compiled patterns that use

     \p or \P will have to recompile them.

 22. Added "Any" and "L&" to the supported property types.

 23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,

     but give a compile time error if the value is greater than 0xff.

 24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were

     accidentally not being installed or uninstalled.

 25. The pcre.h file was built from pcre.h.in, but the only changes that were

     made were to insert the current release number. This seemed silly, because

     it made things harder for people building PCRE on systems that don't run

     "configure". I have turned pcre.h into a distributed file, no longer built

     by "configure", with the version identification directly included. There is

     no longer a pcre.h.in file.

     However, this change necessitated a change to the pcre-config script as

     well. It is built from pcre-config.in, and one of the substitutions was the

     release number. I have updated configure.ac so that ./configure now finds

     the release number by grepping pcre.h.

 26. Added the ability to run the tests under valgrind.

 Version 6.4 05-Sep-05

 ---------------------

  1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines

     "--" to be printed when multiple files were scanned, even when none of the

     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I

     consider it to be a bug, and have restored the previous behaviour.

  2. A couple of code tidies to get rid of compiler warnings.

  3. The pcretest program used to cheat by referring to symbols in the library

     whose names begin with _pcre_. These are internal symbols that are not

     really supposed to be visible externally, and in some environments it is

     possible to suppress them. The cheating is now confined to including

     certain files from the library's source, which is a bit cleaner.

  4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the

     file's purpose clearer.

  5. Reorganized pcre_ucp_findchar().

 Version 6.3 15-Aug-05

 ---------------------

  1. The file libpcre.pc.in did not have general read permission in the tarball.

  2. There were some problems when building without C++ support:

     (a) If C++ support was not built, "make install" and "make test" still

         tried to test it.

     (b) There were problems when the value of CXX was explicitly set. Some

         changes have been made to try to fix these, and ...

     (c) --disable-cpp can now be used to explicitly disable C++ support.

     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a

         backslash in a target when C++ was disabled. This confuses some

         versions of "make", apparently. Using an intermediate variable solves

         this. (Same for CPP_LOBJ.)

  3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)

     (non-Windows) now includes $(CFLAGS) because these flags are sometimes

     necessary on certain architectures.

  4. Added a setting of -export-symbols-regex to the link command to remove

     those symbols that are exported in the C sense, but actually are local

     within the library, and not documented. Their names all begin with

     "_pcre_". This is not a perfect job, because (a) we have to except some

     symbols that pcretest ("illegally") uses, and (b) the facility isn't always

     available (and never for static libraries). I have made a note to try to

     find a way round (a) in the future.

 Version 6.2 01-Aug-05

 ---------------------

  1. There was no test for integer overflow of quantifier values. A construction

     such as {1111111111111111} would give undefined results. What is worse, if

     a minimum quantifier for a parenthesized subpattern overflowed and became

     negative, the calculation of the memory size went wrong. This could have

     led to memory overwriting.

  2. Building PCRE using VPATH was broken. Hopefully it is now fixed.

  3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like

     operating environments where this matters.

  4. Applied Giuseppe Maxia's patch to add additional features for controlling

     PCRE options from within the C++ wrapper.

  5. Named capturing subpatterns were not being correctly counted when a pattern

     was compiled. This caused two problems: (a) If there were more than 100

     such subpatterns, the calculation of the memory needed for the whole

     compiled pattern went wrong, leading to an overflow error. (b) Numerical

     back references of the form \12, where the number was greater than 9, were

     not recognized as back references, even though there were sufficient

     previous subpatterns.

  6. Two minor patches to pcrecpp.cc in order to allow it to compile on older

     versions of gcc, e.g. 2.95.4.

 Version 6.1 21-Jun-05

 ---------------------

  1. There was one reference to the variable "posix" in pcretest.c that was not

     surrounded by "#if !defined NOPOSIX".

  2. Make it possible to compile pcretest without DFA support, UTF8 support, or

     the cross-check on the old pcre_info() function, for the benefit of the

     cut-down version of PCRE that is currently imported into Exim.

  3. A (silly) pattern starting with (?i)(?-i) caused an internal space

     allocation error. I've done the easy fix, which wastes 2 bytes for sensible

     patterns that start (?i) but I don't think that matters. The use of (?i) is

     just an example; this all applies to the other options as well.

  4. Since libtool seems to echo the compile commands it is issuing, the output

     from "make" can be reduced a bit by putting "@" in front of each libtool

     compile command.

  5. Patch from the folks at Google for configure.in to be a bit more thorough

     in checking for a suitable C++ installation before trying to compile the

     C++ stuff. This should fix a reported problem when a compiler was present,

     but no suitable headers.

  6. The man pages all had just "PCRE" as their title. I have changed them to

     be the relevant file name. I have also arranged that these names are

     retained in the file doc/pcre.txt, which is a concatenation in text format

     of all the man pages except the little individual ones for each function.

  7. The NON-UNIX-USE file had not been updated for the different set of source

     files that come with release 6. I also added a few comments about the C++

     wrapper.

 Version 6.0 07-Jun-05

 ---------------------

  1. Some minor internal re-organization to help with my DFA experiments.

  2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that

     didn't matter for the library itself when fully configured, but did matter

     when compiling without UCP support, or within Exim, where the ucp files are

     not imported.

  3. Refactoring of the library code to split up the various functions into

     different source modules. The addition of the new DFA matching code (see

     below) to a single monolithic source would have made it really too

     unwieldy, quite apart from causing all the code to be include in a

     statically linked application, when only some functions are used. This is

     relevant even without the DFA addition now that patterns can be compiled in

     one application and matched in another.

     The downside of splitting up is that there have to be some external

     functions and data tables that are used internally in different modules of

     the library but which are not part of the API. These have all had their

     names changed to start with "_pcre_" so that they are unlikely to clash

     with other external names.

  4. Added an alternate matching function, pcre_dfa_exec(), which matches using

     a different (DFA) algorithm. Although it is slower than the original

     function, it does have some advantages for certain types of matching

     problem.

  5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),

     including restarting after a partial match.

  6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not

     defined when compiling for Windows was sent to me. I have put it into the

     code, though I have no means of testing or verifying it.

  7. Added the pcre_refcount() auxiliary function.

  8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to

     match before or at the first newline in the subject string. In pcretest,

     the /f option on a pattern can be used to set this.

  9. A repeated \w when used in UTF-8 mode with characters greater than 256

     would behave wrongly. This has been present in PCRE since release 4.0.

 10. A number of changes to the pcregrep command:

     (a) Refactored how -x works; insert ^(...)$ instead of setting

         PCRE_ANCHORED and checking the length, in preparation for adding

         something similar for -w.

     (b) Added the -w (match as a word) option.

     (c) Refactored the way lines are read and buffered so as to have more

         than one at a time available.

     (d) Implemented a pcregrep test script.

     (e) Added the -M (multiline match) option. This allows patterns to match

         over several lines of the subject. The buffering ensures that at least

         8K, or the rest of the document (whichever is the shorter) is available

         for matching (and similarly the previous 8K for lookbehind assertions).

     (f) Changed the --help output so that it now says

           -w, --word-regex(p)

         instead of two lines, one with "regex" and the other with "regexp"

         because that confused at least one person since the short forms are the

         same. (This required a bit of code, as the output is generated

         automatically from a table. It wasn't just a text change.)

     (g) -- can be used to terminate pcregrep options if the next thing isn't an

         option but starts with a hyphen. Could be a pattern or a path name

         starting with a hyphen, for instance.

     (h) "-" can be given as a file name to represent stdin.

     (i) When file names are being printed, "(standard input)" is used for

         the standard input, for compatibility with GNU grep. Previously

         "<stdin>" was used.

     (j) The option --label=xxx can be used to supply a name to be used for

         stdin when file names are being printed. There is no short form.

     (k) Re-factored the options decoding logic because we are going to add

         two more options that take data. Such options can now be given in four

         different ways, e.g. "-fname", "-f name", "--file=name", "--file name".

     (l) Added the -A, -B, and -C options for requesting that lines of context

         around matches be printed.

     (m) Added the -L option to print the names of files that do not contain

         any matching lines, that is, the complement of -l.

     (n) The return code is 2 if any file cannot be opened, but pcregrep does

         continue to scan other files.

     (o) The -s option was incorrectly implemented. For compatibility with other

         greps, it now suppresses the error message for a non-existent or non-

         accessible file (but not the return code). There is a new option called

         -q that suppresses the output of matching lines, which was what -s was

         previously doing.

     (p) Added --include and --exclude options to specify files for inclusion

         and exclusion when recursing.

 11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.

     Hopefully, it now does.

 12. Missing cast in pcre_study().

 13. Added an "uninstall" target to the makefile.

 14. Replaced "extern" in the function prototypes in Makefile.in with

     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix

     world, but is set differently for Windows.

 15. Added a second compiling function called pcre_compile2(). The only

     difference is that it has an extra argument, which is a pointer to an

     integer error code. When there is a compile-time failure, this is set

     non-zero, in addition to the error test pointer being set to point to an

     error message. The new argument may be NULL if no error number is required

     (but then you may as well call pcre_compile(), which is now just a

     wrapper). This facility is provided because some applications need a

     numeric error indication, but it has also enabled me to tidy up the way

     compile-time errors are handled in the POSIX wrapper.

 16. Added VPATH=.libs to the makefile; this should help when building with one

     prefix path and installing with another. (Or so I'm told by someone who

     knows more about this stuff than I do.)

 17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This

     passes PCRE_DOTALL to the pcre_compile() function, making the "." character

     match everything, including newlines. This is not POSIX-compatible, but

     somebody wanted the feature. From pcretest it can be activated by using

     both the P and the s flags.

 18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.

 19. libpcre.pc was being incorrectly installed as executable.

 20. A couple of places in pcretest check for end-of-line by looking for '\n';

     it now also looks for '\r' so that it will work unmodified on Windows.

 21. Added Google's contributed C++ wrapper to the distribution.

 22. Added some untidy missing memory free() calls in pcretest, to keep

     Electric Fence happy when testing.

 Version 5.0 13-Sep-04

 ---------------------

  1. Internal change: literal characters are no longer packed up into items

     containing multiple characters in a single byte-string. Each character

     is now matched using a separate opcode. However, there may be more than one

     byte in the character in UTF-8 mode.

  2. The pcre_callout_block structure has two new fields: pattern_position and

     next_item_length. These contain the offset in the pattern to the next match

     item, and its length, respectively.

  3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic

     insertion of callouts before each pattern item. Added the /C option to

     pcretest to make use of this.

  4. On the advice of a Windows user, the lines

       #if defined(_WIN32) || defined(WIN32)

       _setmode( _fileno( stdout ), 0x8000 );

       #endif  /* defined(_WIN32) || defined(WIN32) */

     have been added to the source of pcretest. This apparently does useful

     magic in relation to line terminators.

  5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"

     for the benefit of those environments where the "b" makes a difference.

  6. The icc compiler has the same options as gcc, but "configure" doesn't seem

     to know about it. I have put a hack into configure.in that adds in code

     to set GCC=yes if CC=icc. This seems to end up at a point in the

     generated configure script that is early enough to affect the setting of

     compiler options, which is what is needed, but I have no means of testing

     whether it really works. (The user who reported this had patched the

     generated configure script, which of course I cannot do.)

     LATER: After change 22 below (new libtool files), the configure script

     seems to know about icc (and also ecc). Therefore, I have commented out

     this hack in configure.in.

  7. Added support for pkg-config (2 patches were sent in).

  8. Negated POSIX character classes that used a combination of internal tables

     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and

     [[:^ascii]]. Typically, they would match almost any characters. The other

     POSIX classes were not broken in this way.

  9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed

     to find the match, as PCRE was deluded into thinking that the match had to

     start at the start point or following a newline. The same bug applied to

     patterns with negative forward assertions or any backward assertions

     preceding ".*" at the start, unless the pattern required a fixed first

     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.

 10. In UTF-8 mode, when moving forwards in the subject after a failed match

     starting at the last subject character, bytes beyond the end of the subject

     string were read.

 11. Renamed the variable "class" as "classbits" to make life easier for C++

     users. (Previously there was a macro definition, but it apparently wasn't

     enough.)

 12. Added the new field "tables" to the extra data so that tables can be passed

     in at exec time, or the internal tables can be re-selected. This allows

     a compiled regex to be saved and re-used at a later time by a different

     program that might have everything at different addresses.

 13. Modified the pcre-config script so that, when run on Solaris, it shows a

     -R library as well as a -L library.

 14. The debugging options of pcretest (-d on the command line or D on a

     pattern) showed incorrect output for anything following an extended class

     that contained multibyte characters and which was followed by a quantifier.

 15. Added optional support for general category Unicode character properties

     via the \p, \P, and \X escapes. Unicode property support implies UTF-8

     support. It adds about 90K to the size of the library. The meanings of the

     inbuilt class escapes such as \d and \s have NOT been changed.

 16. Updated pcredemo.c to include calls to free() to release the memory for the

     compiled pattern.

 17. The generated file chartables.c was being created in the source directory

     instead of in the building directory. This caused the build to fail if the

     source directory was different from the building directory, and was

     read-only.

 18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE

     file. No doubt somebody will tell me if they don't make sense... Also added

     Dan Mooney's comments about building on OpenVMS.

 19. Added support for partial matching via the PCRE_PARTIAL option for

     pcre_exec() and the \P data escape in pcretest.

 20. Extended pcretest with 3 new pattern features:

     (i)   A pattern option of the form ">rest-of-line" causes pcretest to

           write the compiled pattern to the file whose name is "rest-of-line".

           This is a straight binary dump of the data, with the saved pointer to

           the character tables forced to be NULL. The study data, if any, is

           written too. After writing, pcretest reads a new pattern.

     (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a

           compiled pattern from the given file. There must not be any

           occurrences of "<" in the file name (pretty unlikely); if there are,

           pcretest will instead treat the initial "<" as a pattern delimiter.

           After reading in the pattern, pcretest goes on to read data lines as

           usual.

     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit

           and 16-bit fields in a compiled pattern, to simulate a pattern that

           was compiled on a host of opposite endianness.

 21. The pcre-exec() function can now cope with patterns that were compiled on

     hosts of opposite endianness, with this restriction:

       As for any compiled expression that is saved and used later, the tables

       pointer field cannot be preserved; the extra_data field in the arguments

       to pcre_exec() should be used to pass in a tables address if a value

       other than the default internal tables were used at compile time.

 22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is

     now diagnosed as an error. Previously, most of the time, a negative number

     would have been treated as zero, but if in addition "ovector" was passed as

     NULL, a crash could occur.

 23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with

     new versions from the libtool 1.5 distribution (the last one is a copy of

     a file called libtool.m4). This seems to have fixed the need to patch

     "configure" to support Darwin 1.3 (which I used to do). However, I still

     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my

     workstation).

 24. Changed the PCRE licence to be the more standard "BSD" licence.

 Version 4.5 01-Dec-03

 ---------------------

  1. There has been some re-arrangement of the code for the match() function so

     that it can be compiled in a version that does not call itself recursively.

     Instead, it keeps those local variables that need separate instances for

     each "recursion" in a frame on the heap, and gets/frees frames whenever it

     needs to "recurse". Keeping track of where control must go is done by means

     of setjmp/longjmp. The whole thing is implemented by a set of macros that

     hide most of the details from the main code, and operates only if

     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the

     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of

     operating.

     To make it easier for callers to provide specially tailored get/free

     functions for this usage, two new functions, pcre_stack_malloc, and

     pcre_stack_free, are used. They are always called in strict stacking order,

     and the size of block requested is always the same.

     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether

     PCRE has been compiled to use the stack or the heap for recursion. The

     -C option of pcretest uses this to show which version is compiled.

     A new data escape \S, is added to pcretest; it causes the amounts of store

     obtained and freed by both kinds of malloc/free at match time to be added

     to the output.

  2. Changed the locale test to use "fr_FR" instead of "fr" because that's

     what's available on my current Linux desktop machine.

  3. When matching a UTF-8 string, the test for a valid string at the start has

     been extended. If start_offset is not zero, PCRE now checks that it points

     to a byte that is the start of a UTF-8 character. If not, it returns

     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;

     this is necessary because there may be backward assertions in the pattern.

     When matching the same subject several times, it may save resources to use

     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.

  4. The code for checking the validity of UTF-8 strings has been tightened so

     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings

     containing "overlong sequences".

  5. Fixed a bug (appearing twice) that I could not find any way of exploiting!

     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"

     should have been "&", but it just so happened that all the cases this let

     through by mistake were picked up later in the function.

  6. I had used a variable called "isblank" - this is a C99 function, causing

     some compilers to warn. To avoid this, I renamed it (as "blankclass").

  7. Cosmetic: (a) only output another newline at the end of pcretest if it is

     prompting; (b) run "./pcretest /dev/null" at the start of the test script

     so the version is shown; (c) stop "make test" echoing "./RunTest".

  8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.

  9. The prototype for memmove() for systems that don't have it was using

     size_t, but the inclusion of the header that defines size_t was later. I've

     moved the #includes for the C headers earlier to avoid this.

 10. Added some adjustments to the code to make it easier to compiler on certain

     special systems:

       (a) Some "const" qualifiers were missing.

       (b) Added the macro EXPORT before all exported functions; by default this

           is defined to be empty.

       (c) Changed the dftables auxiliary program (that builds chartables.c) so

           that it reads its output file name as an argument instead of writing

           to the standard output and assuming this can be redirected.

 11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character

     class containing characters with values greater than 255, PCRE compilation

     went into a loop.

 12. A recursive reference to a subpattern that was within another subpattern

     that had a minimum quantifier of zero caused PCRE to crash. For example,

     (x(y(?2))z)? provoked this bug with a subject that got as far as the

     recursion. If the recursively-called subpattern itself had a zero repeat,

     that was OK.

 13. In pcretest, the buffer for reading a data line was set at 30K, but the

     buffer into which it was copied (for escape processing) was still set at

     1024, so long lines caused crashes.

 14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error

     "internal error: code overflow...". This applied to any character class

     that was followed by a possessive quantifier.

 15. Modified the Makefile to add libpcre.la as a prerequisite for

     libpcreposix.la because I was told this is needed for a parallel build to

     work.

 16. If a pattern that contained .* following optional items at the start was

     studied, the wrong optimizing data was generated, leading to matching

     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any

     matching string must start with a or b or c. The correct conclusion for

     this pattern is that a match can start with any character.

 Version 4.4 13-Aug-03

 ---------------------

  1. In UTF-8 mode, a character class containing characters with values between

     127 and 255 was not handled correctly if the compiled pattern was studied.

     In fixing this, I have also improved the studying algorithm for such

     classes (slightly).

  2. Three internal functions had redundant arguments passed to them. Removal

     might give a very teeny performance improvement.

  3. Documentation bug: the value of the capture_top field in a callout is *one

     more than* the number of the hightest numbered captured substring.

  4. The Makefile linked pcretest and pcregrep with -lpcre, which could result

     in incorrectly linking with a previously installed version. They now link

     explicitly with libpcre.la.

  5. configure.in no longer needs to recognize Cygwin specially.

  6. A problem in pcre.in for Windows platforms is fixed.

  7. If a pattern was successfully studied, and the -d (or /D) flag was given to

     pcretest, it used to include the size of the study block as part of its

     output. Unfortunately, the structure contains a field that has a different

     size on different hardware architectures. This meant that the tests that

     showed this size failed. As the block is currently always of a fixed size,

     this information isn't actually particularly useful in pcretest output, so

     I have just removed it.

  8. Three pre-processor statements accidentally did not start in column 1.

     Sadly, there are *still* compilers around that complain, even though

     standard C has not required this for well over a decade. Sigh.

  9. In pcretest, the code for checking callouts passed small integers in the

     callout_data field, which is a void * field. However, some picky compilers

     complained about the casts involved for this on 64-bit systems. Now

     pcretest passes the address of the small integer instead, which should get

     rid of the warnings.

 10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at

     both compile and run time, and gives an error if an invalid UTF-8 sequence

     is found. There is a option for disabling this check in cases where the

     string is known to be correct and/or the maximum performance is wanted.

 11. In response to a bug report, I changed one line in Makefile.in from

         -Wl,--out-implib,.libs/lib@[email protected] \

     to

         -Wl,--out-implib,.libs/@[email protected] \

     to look similar to other lines, but I have no way of telling whether this

     is the right thing to do, as I do not use Windows. No doubt I'll get told

     if it's wrong...

 Version 4.3 21-May-03

 ---------------------

 1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the

    Makefile.

 2. Some refactoring to improve the quality of the code:

    (i)   The utf8_table... variables are now declared "const".

    (ii)  The code for \cx, which used the "case flipping" table to upper case

          lower case letters, now just substracts 32. This is ASCII-specific,

          but the whole concept of \cx is ASCII-specific, so it seems

          reasonable.

    (iii) PCRE was using its character types table to recognize decimal and

          hexadecimal digits in the pattern. This is silly, because it handles

          only 0-9, a-f, and A-F, but the character types table is locale-

          specific, which means strange things might happen. A private

          table is now used for this - though it costs 256 bytes, a table is

          much faster than multiple explicit tests. Of course, the standard

          character types table is still used for matching digits in subject

          strings against \d.

    (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers

          ending in _t are). So I've renamed it as ESC_tee.

 3. The first argument for regexec() in the POSIX wrapper should have been

    defined as "const".

 4. Changed pcretest to use malloc() for its buffers so that they can be

    Electric Fenced for debugging.

 5. There were several places in the code where, in UTF-8 mode, PCRE would try

    to read one or more bytes before the start of the subject string. Often this

    had no effect on PCRE's behaviour, but in some circumstances it could

    provoke a segmentation fault.

 6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE

    to try to read one or more bytes before the start of the subject string.

 7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with

    UTF-8 support could misbehave in various ways if the subject string

    contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind

    area. (PCRE was not checking for the UTF-8 mode flag, and trying to move

    back over UTF-8 characters.)

 Version 4.2 14-Apr-03

 ---------------------

 1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.

 2. Changes to the building process, supplied by Ronald Landheer-Cieslak

      [ON_WINDOWS]: new variable, "#" on non-Windows platforms

      [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms

      [WIN_PREFIX]: new variable, "cyg" for Cygwin

      * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT

        and BUILD_EXEEXT

      Note: automatic setting of the BUILD variables is not yet working

      set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at

        compile-time but not at link-time

      [LINK]: use for linking executables only

      make different versions for Windows and non-Windows

      [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking

        libraries

      [LINK_FOR_BUILD]: new variable

      [OBJEXT]: use throughout

      [EXEEXT]: use throughout

      <winshared>: new target

      <wininstall>: new target

      <dftables.o>: use native compiler

      <dftables>: use native linker

      <install>: handle Windows platform correctly

      <clean>: ditto

      <check>: ditto

      copy DLL to top builddir before testing

    As part of these changes, -no-undefined was removed again. This was reported

    to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea

    in any case.

 3. Some tidies to get rid of compiler warnings:

    . In the match_data structure, match_limit was an unsigned long int, whereas

      match_call_count was an int. I've made them both unsigned long ints.

    . In pcretest the fact that a const uschar * doesn't automatically cast to

      a void * provoked a warning.

    . Turning on some more compiler warnings threw up some "shadow" variables

      and a few more missing casts.

 4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8

    option, a class that contained a single character with a value between 128

    and 255 (e.g. /[\xFF]/) caused PCRE to crash.

 5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8

    option, a class that contained several characters, but with at least one

    whose value was between 128 and 255 caused PCRE to crash.

 Version 4.1 12-Mar-03

 ---------------------

 1. Compiling with gcc -pedantic found a couple of places where casts were

 needed, and a string in dftables.c that was longer than standard compilers are

 required to support.

 2. Compiling with Sun's compiler found a few more places where the code could

 be tidied up in order to avoid warnings.

 3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the

 first of these names is deprecated in the latest Autoconf in favour of the name

 CC_FOR_BUILD, because "host" is typically used to mean the system on which the

 compiled code will be run. I can't find a reference for HOST_CFLAGS, but by

 analogy I have changed it to CFLAGS_FOR_BUILD.

 4. Added -no-undefined to the linking command in the Makefile, because this is

 apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the

 linking step for the pcreposix library.

 5. PCRE was failing to diagnose the case of two named groups with the same

 name.

 6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a

 literal character that is needed in the subject for a match, and scans along to

 ensure that it is present before embarking on the full matching process. This

 saves time in cases of nested unlimited repeats that are never going to match.

 Problem: the scan can take a lot of time if the subject is very long (e.g.

 megabytes), thus penalizing straightforward matches. It is now done only if the

 amount of subject to be scanned is less than 1000 bytes.

 7. A lesser problem with the same optimization is that it was recording the

 first character of an anchored pattern as "needed", thus provoking a search

 right along the subject, even when the first match of the pattern was going to

 fail. The "needed" character is now not set for anchored patterns, unless it

 follows something in the pattern that is of non-fixed length. Thus, it still

 fulfils its original purpose of finding quick non-matches in cases of nested

 unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.

 Version 4.0 17-Feb-03

 ---------------------

 1. If a comment in an extended regex that started immediately after a meta-item

 extended to the end of string, PCRE compiled incorrect data. This could lead to

 all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.

 2. Moved to autoconf 2.53 and libtool 1.4.2.

 3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,

 the special perltest8 script is no longer needed - all the tests can be run

 from a single perltest script.

 4. From 5.004, Perl has not included the VT character (0x0b) in the set defined

 by \s. It has now been removed in PCRE. This means it isn't recognized as

 whitespace in /x regexes too, which is the same as Perl. Note that the POSIX

 class [:space:] *does* include VT, thereby creating a mess.

 5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only

 space and tab.

 6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use

 its new features into the main test script, reducing the number of scripts.

 7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions

 were backward compatible, and made the (?i) apply to the whole pattern, as if

 /i were given. Now it behaves more logically, and applies the option setting

 only to what follows. PCRE has been changed to follow suit. However, if it

 finds options settings right at the start of the pattern, it extracts them into

 the global options, as before. Thus, they show up in the info data.

 8. Added support for the \Q...\E escape sequence. 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 will cause variable

 interpolation. Note the following examples:

     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

 For compatibility with Perl, \Q...\E sequences are recognized inside character

 classes as well as outside them.

 9. Re-organized 3 code statements in pcretest to avoid "overflow in

 floating-point constant arithmetic" warnings from a Microsoft compiler. Added a

 (size_t) cast to one statement in pcretest and one in pcreposix to avoid

 signed/unsigned warnings.

 10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o

 option for pcretest, so I've replaced it by a simple function that does just

 that job.

 11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or

 "pcregrep -".

 12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's

 Java package. This provides some syntactic sugar for simple cases of what my

 documentation calls "once-only subpatterns". A pattern such as x*+ is the same

 as (?>x*). In other words, if what is inside (?>...) is just a single repeated

 item, you can use this simplified notation. Note that only makes sense with

 greedy quantifiers. Consequently, the use of the possessive quantifier forces

 greediness, whatever the setting of the PCRE_UNGREEDY option.

 13. A change of greediness default within a pattern was not taking effect at

 the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized

 subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option

 was abstracted outside.

 14. PCRE now supports the \G assertion. It is true when the current matching

 position is at the start point of the match. This differs from \A when the

 starting offset is non-zero. Used with the /g option of pcretest (or similar

 code), it works in the same way as it does for Perl's /g option. If all

 alternatives of a regex begin with \G, the expression is anchored to the start

 match position, and the "anchored" flag is set in the compiled expression.

 15. Some bugs concerning the handling of certain option changes within patterns

 have been fixed. These applied to options other than (?ims). For example,

 "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have

 been the other way round. Some of this was related to change 7 above.

 16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX

 features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/

 and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports

 POSIX classes only within a class (e.g. /[[:alpha:]]/).

 17. Added support for Perl's \C escape. This matches one byte, even in UTF8

 mode. Unlike ".", it always matches newline, whatever the setting of

 PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind

 assertions. Perl allows it, but it doesn't (in general) work because it can't

 calculate the length of the lookbehind. At least, that's the case for Perl

 5.8.0 - I've been told they are going to document that it doesn't work in

 future.

 18. Added an error diagnosis for escapes that PCRE does not support: these are

 \L, \l, \N, \P, \p, \U, \u, and \X.

 19. Although correctly diagnosing a missing ']' in a character class, PCRE was

 reading past the end of the pattern in cases such as /[abcd/.

 20. PCRE was getting more memory than necessary for patterns with classes that

 contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.

 21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for

 compiling PCRE for use with Virtual Pascal.

 22. Small fix to the Makefile to make it work properly if the build is done

 outside the source tree.

 23. Added a new extension: a condition to go with recursion. If a conditional

 subpattern starts with (?(R) the "true" branch is used if recursion has

 happened, whereas the "false" branch is used only at the top level.

 24. When there was a very long string of literal characters (over 255 bytes

 without UTF support, over 250 bytes with UTF support), the computation of how

 much memory was required could be incorrect, leading to segfaults or other

 strange effects.

 25. PCRE was incorrectly assuming anchoring (either to start of subject or to

 start of line for a non-DOTALL pattern) when a pattern started with (.*) and

 there was a subsequent back reference to those brackets. This meant that, for

 example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't

 possible to check for precisely this case. All we can do is abandon the

 optimization if .* occurs inside capturing brackets when there are any back