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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
43    Version 8.01 19-Jan-2010
44    ------------------------
46    1.  If a pattern contained a conditional subpattern with only one branch (in
47        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
48        computed the wrong minimum data length (which is of course zero for such
49        subpatterns). This could cause incorrect "no match" results.
51    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
52        the pattern is reset in the first branch, pcre_compile() failed with
53        "internal error: code overflow at offset...". This happened only when
54        the reset was to the original external option setting. (An optimization
55        abstracts leading options settings into an external setting, which was the
56        cause of this.)
58    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
59        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
60        assertion pattern did not match (meaning that the assertion was true), it
61        was incorrectly treated as false if the SKIP had been reached during the
62        matching. This also applied to assertions used as conditions.
64    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
65        assertion subpattern, including such a pattern used as a condition,
66        unpredictable results occurred, instead of the error return
69    5.  The C++ GlobalReplace function was not working like Perl for the special
70        situation when an empty string is matched. It now does the fancy magic
71        stuff that is necessary.
73    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
74        removed. (These were left over from very, very early versions of PCRE.)
76    7.  Some cosmetic changes to the code to make life easier when compiling it
77        as part of something else:
79        (a) Change DEBUG to PCRE_DEBUG.
81        (b) In pcre_compile(), rename the member of the "branch_chain" structure
82            called "current" as "current_branch", to prevent a collision with the
83            Linux macro when compiled as a kernel module.
85        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
86            prevent a collision with the Linux macro when compiled as a kernel
87            module.
89    8.  In pcre_compile() there are some checks for integer overflows that used to
90        cast potentially large values to (double). This has been changed to that
91        when building, a check for int64_t is made, and if it is found, it is used
92        instead, thus avoiding the use of floating point arithmetic. (There is no
93        other use of FP in PCRE.) If int64_t is not found, the fallback is to
94        double.
96    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
97        2005 (difference between two addresses compared to an unsigned value).
99    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
100        custom one, because of the following reported problem in Windows:
102          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
103              under Win32.
104          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
105              therefore missing the function definition.
106          - The compiler thus generates a "C" signature for the test function.
107          - The linker fails to find the "C" function.
108          - PCRE fails to configure if asked to do so against libbz2.
110    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
111        messages were output:
113          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
114          rerunning libtoolize, to keep the correct libtool macros in-tree.
115          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
117        I have done both of these things.
119    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
120        most of the time, it *can* run out if it is given a pattern that contains a
121        runaway infinite recursion. I updated the discussion in the pcrestack man
122        page.
124    13. Now that we have gone to the x.xx style of version numbers, the minor
125        version may start with zero. Using 08 or 09 is a bad idea because users
126        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
127        interpreted as invalid octal numbers. I've updated the previous comment in
128        configure.ac, and also added a check that gives an error if 08 or 09 are
129        used.
131    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
132        causing partial matching to fail when the end of the subject matched \W
133        in a UTF-8 pattern where \W was quantified with a minimum of 3.
135    15. There were some discrepancies between the declarations in pcre_internal.h
136        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
137        their definitions. The declarations used "const uschar *" and the
138        definitions used USPTR. Even though USPTR is normally defined as "const
139        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
140        reported that: "This difference in casting confuses some C++ compilers, for
141        example, SunCC recognizes above declarations as different functions and
142        generates broken code for hbpcre." I have changed the declarations to use
143        USPTR.
145    16. GNU libtool is named differently on some systems. The autogen.sh script now
146        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
147        (FreeBSD).
149    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
150        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
151        comment: "Figure out how to create a longlong from a string: strtoll and
152        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
153        instance, but it only takes 2 args instead of 3!"
155    18. A subtle bug concerned with back references has been fixed by a change of
156        specification, with a corresponding code fix. A pattern such as
157        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
158        refers, was giving matches when it shouldn't. For example, xa=xaaa would
159        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
160        same bug. Such groups have to be quantified to be useful, or contained
161        inside another quantified group. (If there's no repetition, the reference
162        can never match.) The problem arises because, having left the group and
163        moved on to the rest of the pattern, a later failure that backtracks into
164        the group uses the captured value from the final iteration of the group
165        rather than the correct earlier one. I have fixed this in PCRE by forcing
166        any group that contains a reference to itself to be an atomic group; that
167        is, there cannot be any backtracking into it once it has completed. This is
168        similar to recursive and subroutine calls.
171    Version 8.00 19-Oct-09
172    ----------------------
174    1.  The table for translating pcre_compile() error codes into POSIX error codes
175        was out-of-date, and there was no check on the pcre_compile() error code
176        being within the table. This could lead to an OK return being given in
177        error.
179    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
180        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
181        in a Windows environment.
183    3.  The pcregrep --count option prints the count for each file even when it is
184        zero, as does GNU grep. However, pcregrep was also printing all files when
185        --files-with-matches was added. Now, when both options are given, it prints
186        counts only for those files that have at least one match. (GNU grep just
187        prints the file name in this circumstance, but including the count seems
188        more useful - otherwise, why use --count?) Also ensured that the
189        combination -clh just lists non-zero counts, with no names.
191    4.  The long form of the pcregrep -F option was incorrectly implemented as
192        --fixed_strings instead of --fixed-strings. This is an incompatible change,
193        but it seems right to fix it, and I didn't think it was worth preserving
194        the old behaviour.
196    5.  The command line items --regex=pattern and --regexp=pattern were not
197        recognized by pcregrep, which required --regex pattern or --regexp pattern
198        (with a space rather than an '='). The man page documented the '=' forms,
199        which are compatible with GNU grep; these now work.
201    6.  No libpcreposix.pc file was created for pkg-config; there was just
202        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
204    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
205        when UCP support is not needed, by modifying the Python script that
206        generates it from Unicode data files. This should not matter if the module
207        is correctly used as a library, but I received one complaint about 50K of
208        unwanted data. My guess is that the person linked everything into his
209        program rather than using a library. Anyway, it does no harm.
211    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
212        was a minimum greater than 1 for a wide character in a possessive
213        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
214        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
215        character. Chaos in the form of incorrect output or a compiling loop could
216        result.
218    9.  The restrictions on what a pattern can contain when partial matching is
219        requested for pcre_exec() have been removed. All patterns can now be
220        partially matched by this function. In addition, if there are at least two
221        slots in the offset vector, the offset of the earliest inspected character
222        for the match and the offset of the end of the subject are set in them when
223        PCRE_ERROR_PARTIAL is returned.
225    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
226        synonymous with PCRE_PARTIAL, for backwards compatibility, and
227        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
228        and may be more useful for multi-segment matching.
230    11. Partial matching with pcre_exec() is now more intuitive. A partial match
231        used to be given if ever the end of the subject was reached; now it is
232        given only if matching could not proceed because another character was
233        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
234        string "Z", which now yields "no match" instead of "partial match". In the
235        case of pcre_dfa_exec(), "no match" is given if every matching path for the
236        final character ended with (*FAIL).
238    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
239        if the pattern had a "must contain" character that was already found in the
240        earlier partial match, unless partial matching was again requested. For
241        example, with the pattern /dog.(body)?/, the "must contain" character is
242        "g". If the first part-match was for the string "dog", restarting with
243        "sbody" failed. This bug has been fixed.
245    13. The string returned by pcre_dfa_exec() after a partial match has been
246        changed so that it starts at the first inspected character rather than the
247        first character of the match. This makes a difference only if the pattern
248        starts with a lookbehind assertion or \b or \B (\K is not supported by
249        pcre_dfa_exec()). It's an incompatible change, but it makes the two
250        matching functions compatible, and I think it's the right thing to do.
252    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
253        so that the demonstration program is easily available in environments where
254        PCRE has not been installed from source.
256    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
257        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
258        library.
260    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
261        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
262        is not the first non-POSIX option to be added. Clearly some people find
263        these options useful.
265    17. If a caller to the POSIX matching function regexec() passes a non-zero
266        value for nmatch with a NULL value for pmatch, the value of
267        nmatch is forced to zero.
269    18. RunGrepTest did not have a test for the availability of the -u option of
270        the diff command, as RunTest does. It now checks in the same way as
271        RunTest, and also checks for the -b option.
273    19. If an odd number of negated classes containing just a single character
274        interposed, within parentheses, between a forward reference to a named
275        subpattern and the definition of the subpattern, compilation crashed with
276        an internal error, complaining that it could not find the referenced
277        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
278        [The bug was that it was starting one character too far in when skipping
279        over the character class, thus treating the ] as data rather than
280        terminating the class. This meant it could skip too much.]
282    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
283        /g option in pcretest when the pattern contains \K, which makes it possible
284        to have an empty string match not at the start, even when the pattern is
285        anchored. Updated pcretest and pcredemo to use this option.
287    21. If the maximum number of capturing subpatterns in a recursion was greater
288        than the maximum at the outer level, the higher number was returned, but
289        with unset values at the outer level. The correct (outer level) value is
290        now given.
292    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
293        PCRE did not set those parentheses (unlike Perl). I have now found a way to
294        make it do so. The string so far is captured, making this feature
295        compatible with Perl.
297    23. The tests have been re-organized, adding tests 11 and 12, to make it
298        possible to check the Perl 5.10 features against Perl 5.10.
300    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
301        pattern matches a fixed length string. PCRE did not allow this; now it
302        does. Neither allows recursion.
304    25. I finally figured out how to implement a request to provide the minimum
305        length of subject string that was needed in order to match a given pattern.
306        (It was back references and recursion that I had previously got hung up
307        on.) This code has now been added to pcre_study(); it finds a lower bound
308        to the length of subject needed. It is not necessarily the greatest lower
309        bound, but using it to avoid searching strings that are too short does give
310        some useful speed-ups. The value is available to calling programs via
311        pcre_fullinfo().
313    26. While implementing 25, I discovered to my embarrassment that pcretest had
314        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
315        study optimizations had never been tested with that matching function.
316        Oops. What is worse, even when it was passed study data, there was a bug in
317        pcre_dfa_exec() that meant it never actually used it. Double oops. There
318        were also very few tests of studied patterns with pcre_dfa_exec().
320    27. If (?| is used to create subpatterns with duplicate numbers, they are now
321        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
322        on the other side of the coin, they are no longer allowed to have different
323        names, because these cannot be distinguished in PCRE, and this has caused
324        confusion. (This is a difference from Perl.)
326    28. When duplicate subpattern names are present (necessarily with different
327        numbers, as required by 27 above), and a test is made by name in a
328        conditional pattern, either for a subpattern having been matched, or for
329        recursion in such a pattern, all the associated numbered subpatterns are
330        tested, and the overall condition is true if the condition is true for any
331        one of them. This is the way Perl works, and is also more like the way
332        testing by number works.
335    Version 7.9 11-Apr-09
336    ---------------------
338    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
339        (pcretest), all targets were linked against these libraries. This included
340        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
341        libraries. This caused unwanted dependencies to be created. This problem
342        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
343        pcretest is linked with readline.
345    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
346        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
347        moved outside it again, because FALSE and TRUE are already defined in AIX,
348        but BOOL is not.
350    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
351        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
353    4.  The pcregrep documentation said spaces were inserted as well as colons (or
354        hyphens) following file names and line numbers when outputting matching
355        lines. This is not true; no spaces are inserted. I have also clarified the
356        wording for the --colour (or --color) option.
358    5.  In pcregrep, when --colour was used with -o, the list of matching strings
359        was not coloured; this is different to GNU grep, so I have changed it to be
360        the same.
362    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
363        each matching line was coloured. Now it goes on to look for further matches
364        of any of the test patterns, which is the same behaviour as GNU grep.
366    7.  A pattern that could match an empty string could cause pcregrep to loop; it
367        doesn't make sense to accept an empty string match in pcregrep, so I have
368        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
369        seems to be how GNU grep behaves.
371    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
372        start or after a newline", because the conditional assertion was not being
373        correctly handled. The rule now is that both the assertion and what follows
374        in the first alternative must satisfy the test.
376    9.  If auto-callout was enabled in a pattern with a conditional group whose
377        condition was an assertion, PCRE could crash during matching, both with
378        pcre_exec() and pcre_dfa_exec().
380    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
381        used for matching.
383    11. Unicode property support in character classes was not working for
384        characters (bytes) greater than 127 when not in UTF-8 mode.
386    12. Added the -M command line option to pcretest.
388    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
390    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
392    16. Added comments and documentation about mis-use of no_arg in the C++
393        wrapper.
395    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
396        from Martin Jerabek that uses macro names for all relevant character and
397        string constants.
399    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
400        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
401        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
402        these, but not everybody uses configure.
404    19. A conditional group that had only one branch was not being correctly
405        recognized as an item that could match an empty string. This meant that an
406        enclosing group might also not be so recognized, causing infinite looping
407        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
408        with the subject "ab", where knowledge that the repeated group can match
409        nothing is needed in order to break the loop.
411    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
412        exec(), but without supplying a callout function, matching went wrong.
414    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
415        leak if the size of the offset vector was greater than 30. When the vector
416        is smaller, the saved offsets during recursion go onto a local stack
417        vector, but for larger vectors malloc() is used. It was failing to free
418        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
419        error, in fact).
421    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
422        heapframe that is used only when UTF-8 support is enabled. This caused no
423        problem, but was untidy.
425    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
426        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
427        included within another project.
429    24. Steven Van Ingelgem's patches to add more options to the CMake support,
430        slightly modified by me:
432          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
433              not building pcregrep.
435          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
436              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
438    25. Forward references, both numeric and by name, in patterns that made use of
439        duplicate group numbers, could behave incorrectly or give incorrect errors,
440        because when scanning forward to find the reference group, PCRE was not
441        taking into account the duplicate group numbers. A pattern such as
442        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
444    26. Changed a few more instances of "const unsigned char *" to USPTR, making
445        the feature of a custom pointer more persuasive (as requested by a user).
447    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
448        pcretest.c, inside #ifndefs, because it seems they are sometimes already
449        pre-defined.
451    28. Added support for (*UTF8) at the start of a pattern.
453    29. Arrange for flags added by the "release type" setting in CMake to be shown
454        in the configuration summary.
457    Version 7.8 05-Sep-08
458    ---------------------
460    1.  Replaced UCP searching code with optimized version as implemented for Ad
461        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
462        stage table and inline lookup instead of a function, giving speed ups of 2
463        to 5 times on some simple patterns that I tested. Permission was given to
464        distribute the MultiStage2.py script that generates the tables (it's not in
465        the tarball, but is in the Subversion repository).
467    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
468        scripts.
470    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
471        a group with a zero qualifier. The result of the study could be incorrect,
472        or the function might crash, depending on the pattern.
474    4.  Caseless matching was not working for non-ASCII characters in back
475        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
476        It now works when Unicode Property Support is available.
478    5.  In pcretest, an escape such as \x{de} in the data was always generating
479        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
480        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
481        truncation.
483    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
485    7.  Added two (int) casts to pcregrep when printing the difference of two
486        pointers, in case they are 64-bit values.
488    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
489        test 2 if it fails.
491    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
492        and a #define of that name to empty if it is not externally set. This is to
493        allow users of MSVC to set it if necessary.
495    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
496        the convenience functions in the pcre_get.c source file.
498    11. An option change at the start of a pattern that had top-level alternatives
499        could cause overwriting and/or a crash. This command provoked a crash in
500        some environments:
502          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
504        This potential security problem was recorded as CVE-2008-2371.
506    12. For a pattern where the match had to start at the beginning or immediately
507        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
508        pcre_dfa_exec() could read past the end of the passed subject if there was
509        no match. To help with detecting such bugs (e.g. with valgrind), I modified
510        pcretest so that it places the subject at the end of its malloc-ed buffer.
512    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
513        exec() might read past the end of the data buffer in UTF-8 mode.
515    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
516        the data contained the byte 0x85 as part of a UTF-8 character within its
517        first line. This applied both to normal and DFA matching.
519    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
520        /^[^d]*?$/8 failed to match "abc".
522    16. Added a missing copyright notice to pcrecpp_internal.h.
524    17. Make it more clear in the documentation that values returned from
525        pcre_exec() in ovector are byte offsets, not character counts.
527    18. Tidied a few places to stop certain compilers from issuing warnings.
529    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
530        supplied by Stefan Weber. I made a further small update for 7.8 because
531        there is a change of source arrangements: the pcre_searchfuncs.c module is
532        replaced by pcre_ucd.c.
535    Version 7.7 07-May-08
536    ---------------------
538    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
539        a string to a long long, pretend we don't even have a long long." This is
540        done by checking for the strtoq, strtoll, and _strtoi64 functions.
542    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
543        pre-7.6 versions, which defined a global no_arg variable instead of putting
544        it in the RE class. (See also #8 below.)
546    3.  Remove a line of dead code, identified by coverity and reported by Nuno
547        Lopes.
549    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
551        (1) The include/exclude patterns were being applied to the whole pathnames
552            of files, instead of just to the final components.
554        (2) If there was more than one level of directory, the subdirectories were
555            skipped unless they satisfied the include/exclude conditions. This is
556            inconsistent with GNU grep (and could even be seen as contrary to the
557            pcregrep specification - which I improved to make it absolutely clear).
558            The action now is always to scan all levels of directory, and just
559            apply the include/exclude patterns to regular files.
561    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
562        --exclude_dir in the tests to avoid scanning .svn directories.
564    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
565        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
566        doesn't support NULs in patterns.
568    7.  Added some missing "const"s to declarations of static tables in
569        pcre_compile.c and pcre_dfa_exec.c.
571    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
572        caused by fix #2  above. (Subsequently also a second patch to fix the
573        first patch. And a third patch - this was a messy problem.)
575    9.  Applied Craig's patch to remove the use of push_back().
577    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
578        matching function regexec().
580    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
581        which, however, unlike Perl's \g{...}, are subroutine calls, not back
582        references. PCRE supports relative numbers with this syntax (I don't think
583        Oniguruma does).
585    12. Previously, a group with a zero repeat such as (...){0} was completely
586        omitted from the compiled regex. However, this means that if the group
587        was called as a subroutine from elsewhere in the pattern, things went wrong
588        (an internal error was given). Such groups are now left in the compiled
589        pattern, with a new opcode that causes them to be skipped at execution
590        time.
592    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
593        to the way PCRE behaves:
595        (a) A lone ] character is dis-allowed (Perl treats it as data).
597        (b) A back reference to an unmatched subpattern matches an empty string
598            (Perl fails the current match path).
600        (c) A data ] in a character class must be notated as \] because if the
601            first data character in a class is ], it defines an empty class. (In
602            Perl it is not possible to have an empty class.) The empty class []
603            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
604            The negative empty class [^] matches any one character, independently
605            of the DOTALL setting.
607    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
608        non-existent subpattern following a character class starting with ']' and
609        containing () gave an internal compiling error instead of "reference to
610        non-existent subpattern". Fortunately, when the pattern did exist, the
611        compiled code was correct. (When scanning forwards to check for the
612        existencd of the subpattern, it was treating the data ']' as terminating
613        the class, so got the count wrong. When actually compiling, the reference
614        was subsequently set up correctly.)
616    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
617        it was being rejected as not supported by pcre_dfa_exec(), even though
618        other assertions are supported. I have made pcre_dfa_exec() support
619        (*FAIL).
621    16. The implementation of 13c above involved the invention of a new opcode,
622        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
623        cannot be changed at match time, I realized I could make a small
624        improvement to matching performance by compiling OP_ALLANY instead of
625        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
626        on the OP_ANY path.
628    17. Compiling pcretest on Windows with readline support failed without the
629        following two fixes: (1) Make the unistd.h include conditional on
630        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
632    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
633        ncurses library to be included for pcretest when ReadLine support is
634        requested, but also to allow for it to be overridden. This patch came from
635        Daniel Bergström.
637    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
638        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
639        any errors with the current Unicode tables. Thanks to Peter Kankowski for
640        spotting this.
643    Version 7.6 28-Jan-08
644    ---------------------
646    1.  A character class containing a very large number of characters with
647        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
648        overflow.
650    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
651        HAVE_LONG_LONG is not defined.
653    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
654        bring them up to date and include new features. This patch includes:
656        - Fixed PH's badly added libz and libbz2 support.
657        - Fixed a problem with static linking.
658        - Added pcredemo. [But later removed - see 7 below.]
659        - Fixed dftables problem and added an option.
660        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
661            HAVE_LONG_LONG.
662        - Added readline support for pcretest.
663        - Added an listing of the option settings after cmake has run.
665    4.  A user submitted a patch to Makefile that makes it easy to create
666        "pcre.dll" under mingw when using Configure/Make. I added stuff to
667        Makefile.am that cause it to include this special target, without
668        affecting anything else. Note that the same mingw target plus all
669        the other distribution libraries and programs are now supported
670        when configuring with CMake (see 6 below) instead of with
671        Configure/Make.
673    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
674        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
675        exported in the Windows port". It has not yet been confirmed that the patch
676        solves the problem, but it does no harm.
678    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
679        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
680        with CMake, and also correct the comment about stack recursion.
682    7.  Remove the automatic building of pcredemo from the ./configure system and
683        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
684        of a program that users should build themselves after PCRE is installed, so
685        building it automatically is not really right. What is more, it gave
686        trouble in some build environments.
688    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
691    Version 7.5 10-Jan-08
692    ---------------------
694    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
695        values in parens when parsing an RE using the C++ wrapper."
697    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
698        Characters greater than 255 were excluded from the class instead of being
699        included.
701    3.  The same bug as (2) above applied to negated POSIX classes such as
702        [:^space:].
704    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
705        defined or documented. It seems to have been a typo for PCRE_STATIC, so
706        I have changed it.
708    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
709        first named subpattern) and a construct such as (?&a) would reference the
710        first named subpattern whose name started with "a" (in other words, the
711        length check was missing). Both these problems are fixed. "Subpattern name
712        expected" is now given for (?&) (a zero-length name), and this patch also
713        makes it give the same error for \k'' (previously it complained that that
714        was a reference to a non-existent subpattern).
716    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
717        this is right because (?- can be followed by option settings as well as by
718        digits. I have, however, made the messages clearer.
720    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
721        than the number used in the conditional) now cause a compile-time error.
722        This is actually not compatible with Perl, which accepts such patterns, but
723        treats the conditional as always being FALSE (as PCRE used to), but it
724        seems to me that giving a diagnostic is better.
726    8.  Change "alphameric" to the more common word "alphanumeric" in comments
727        and messages.
729    9.  Fix two occurrences of "backslash" in comments that should have been
730        "backspace".
732    10. Remove two redundant lines of code that can never be obeyed (their function
733        was moved elsewhere).
735    11. The program that makes PCRE's Unicode character property table had a bug
736        which caused it to generate incorrect table entries for sequences of
737        characters that have the same character type, but are in different scripts.
738        It amalgamated them into a single range, with the script of the first of
739        them. In other words, some characters were in the wrong script. There were
740        thirteen such cases, affecting characters in the following ranges:
742          U+002b0 - U+002c1
743          U+0060c - U+0060d
744          U+0061e - U+00612
745          U+0064b - U+0065e
746          U+0074d - U+0076d
747          U+01800 - U+01805
748          U+01d00 - U+01d77
749          U+01d9b - U+01dbf
750          U+0200b - U+0200f
751          U+030fc - U+030fe
752          U+03260 - U+0327f
753          U+0fb46 - U+0fbb1
754          U+10450 - U+1049d
756    12. The -o option (show only the matching part of a line) for pcregrep was not
757        compatible with GNU grep in that, if there was more than one match in a
758        line, it showed only the first of them. It now behaves in the same way as
759        GNU grep.
761    13. If the -o and -v options were combined for pcregrep, it printed a blank
762        line for every non-matching line. GNU grep prints nothing, and pcregrep now
763        does the same. The return code can be used to tell if there were any
764        non-matching lines.
766    14. Added --file-offsets and --line-offsets to pcregrep.
768    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
769        infinitely looping recursion. The bug was that positive lookaheads were not
770        being skipped when checking for a possible empty match (negative lookaheads
771        and both kinds of lookbehind were skipped).
773    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
774        inclusion of <windows.h> to before rather than after the definition of
775        INVALID_FILE_ATTRIBUTES (patch from David Byron).
777    17. Specifying a possessive quantifier with a specific limit for a Unicode
778        character property caused pcre_compile() to compile bad code, which led at
779        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
780        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
781        caused the error; without that there was no problem.
783    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
785    19. Added --enable-pcretest-libreadline.
787    20. In pcrecpp.cc, the variable 'count' was incremented twice in
788        RE::GlobalReplace(). As a result, the number of replacements returned was
789        double what it should be. I removed one of the increments, but Craig sent a
790        later patch that removed the other one (the right fix) and added unit tests
791        that check the return values (which was not done before).
793    21. Several CMake things:
795        (1) Arranged that, when cmake is used on Unix, the libraries end up with
796            the names libpcre and libpcreposix, not just pcre and pcreposix.
798        (2) The above change means that pcretest and pcregrep are now correctly
799            linked with the newly-built libraries, not previously installed ones.
803    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
804        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
805        UTF-8 newline character). The key issue is that the pattern starts .*;
806        this means that the match must be either at the beginning, or after a
807        newline. The bug was in the code for advancing after a failed match and
808        checking that the new position followed a newline. It was not taking
809        account of UTF-8 characters correctly.
811    23. PCRE was behaving differently from Perl in the way it recognized POSIX
812        character classes. PCRE was not treating the sequence [:...:] as a
813        character class unless the ... were all letters. Perl, however, seems to
814        allow any characters between [: and :], though of course it rejects as
815        unknown any "names" that contain non-letters, because all the known class
816        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
817        for example, whereas PCRE did not - it did not recognize a POSIX character
818        class. This seemed a bit dangerous, so the code has been changed to be
819        closer to Perl. The behaviour is not identical to Perl, because PCRE will
820        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
821        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
822        Perl does, and where it didn't before.
824    24. Rewrite so as to remove the single use of %n from pcregrep because in some
825        Windows environments %n is disabled by default.
828    Version 7.4 21-Sep-07
829    ---------------------
831    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
832        means that a class such as [\s] counted as "explicit reference to CR or
833        LF". That isn't really right - the whole point of the change was to try to
834        help when there was an actual mention of one of the two characters. So now
835        the change happens only if \r or \n (or a literal CR or LF) character is
836        encountered.
838    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
839        of both had grown to the point where there were only 3 bits left.
840        Fortunately, there was spare space in the data structure, and so I have
841        moved the internal flags into a new 16-bit field to free up more option
842        bits.
844    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
845        but did not set the internal JCHANGED flag - either of these is enough to
846        control the way the "get" function works - but the PCRE_INFO_JCHANGED
847        facility is supposed to tell if (?J) was ever used, so now (?J) at the
848        start sets both bits.
850    4.  Added options (at build time, compile time, exec time) to change \R from
851        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
853    5.  doc/pcresyntax.html was missing from the distribution.
855    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
856        compatibility, even though it is no longer used.
858    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
859        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
860        windows.h file is present (where different names are used). [This was
861        reversed later after testing - see 16 below.]
863    8.  Changed all #include <config.h> to #include "config.h". There were also
864        some further <pcre.h> cases that I changed to "pcre.h".
866    9.  When pcregrep was used with the --colour option, it missed the line ending
867        sequence off the lines that it output.
869    10. It was pointed out to me that arrays of string pointers cause lots of
870        relocations when a shared library is dynamically loaded. A technique of
871        using a single long string with a table of offsets can drastically reduce
872        these. I have refactored PCRE in four places to do this. The result is
873        dramatic:
875          Originally:                          290
876          After changing UCP table:            187
877          After changing error message table:   43
878          After changing table of "verbs"       36
879          After changing table of Posix names   22
881        Thanks to the folks working on Gregex for glib for this insight.
883    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
884        unicode-properties was also set.
886    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
888    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
889        checked only for CRLF.
891    14. Added casts to pcretest.c to avoid compiler warnings.
893    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
895    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
896        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
897        entirely. This removes changes made in 7 above.
899    17. The CMake files have been updated, and there is now more information about
900        building with CMake in the NON-UNIX-USE document.
903    Version 7.3 28-Aug-07
904    ---------------------
906     1. In the rejigging of the build system that eventually resulted in 7.1, the
907        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
908        brackets there is not right, since it causes compilers to look for an
909        installed pcre.h, not the version that is in the source that is being
910        compiled (which of course may be different). I have changed it back to:
912          #include "pcre.h"
914        I have a vague recollection that the change was concerned with compiling in
915        different directories, but in the new build system, that is taken care of
916        by the VPATH setting the Makefile.
918     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
919        when the subject happened to end in the byte 0x85 (e.g. if the last
920        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
921        characters but of course it shouldn't be taken as a newline when it is part
922        of another character. The bug was that, for an unlimited repeat of . in
923        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
924        characters when looking for a newline.
926     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
928     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
929        in debug output.
931     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
932        long printing in the pcrecpp unittest when running under MinGW.
934     6. ESC_K was left out of the EBCDIC table.
936     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
937        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
938        limit also applies to "virtual nesting" when a pattern is recursive, and in
939        this case 1000 isn't so big. I have been able to remove this limit at the
940        expense of backing off one optimization in certain circumstances. Normally,
941        when pcre_exec() would call its internal match() function recursively and
942        immediately return the result unconditionally, it uses a "tail recursion"
943        feature to save stack. However, when a subpattern that can match an empty
944        string has an unlimited repetition quantifier, it no longer makes this
945        optimization. That gives it a stack frame in which to save the data for
946        checking that an empty string has been matched. Previously this was taken
947        from the 1000-entry workspace that had been reserved. So now there is no
948        explicit limit, but more stack is used.
950     8. Applied Daniel's patches to solve problems with the import/export magic
951        syntax that is required for Windows, and which was going wrong for the
952        pcreposix and pcrecpp parts of the library. These were overlooked when this
953        problem was solved for the main library.
955     9. There were some crude static tests to avoid integer overflow when computing
956        the size of patterns that contain repeated groups with explicit upper
957        limits. As the maximum quantifier is 65535, the maximum group length was
958        set at 30,000 so that the product of these two numbers did not overflow a
959        32-bit integer. However, it turns out that people want to use groups that
960        are longer than 30,000 bytes (though not repeat them that many times).
961        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
962        made it possible to implement the integer overflow checks in a much more
963        dynamic way, which I have now done. The artificial limitation on group
964        length has been removed - we now have only the limit on the total length of
965        the compiled pattern, which depends on the LINK_SIZE setting.
967    10. Fixed a bug in the documentation for get/copy named substring when
968        duplicate names are permitted. If none of the named substrings are set, the
969        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
970        empty string.
972    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
973        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
974        because the ] is interpreted as the first data character and the
975        terminating ] is not found. PCRE has been made compatible with Perl in this
976        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
977        cause memory overwriting.
979    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
980        string has been matched (to stop an infinite loop). It was not recognizing
981        a conditional subpattern that could match an empty string if that
982        subpattern was within another subpattern. For example, it looped when
983        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
984        condition was not nested. This bug has been fixed.
986    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
987        past the start of the subject in the presence of bytes with the top bit
988        set, for example "\x8aBCD".
990    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
991        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
993    14. Optimized (?!) to (*FAIL).
995    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
996        This restricts code points to be within the range 0 to 0x10FFFF, excluding
997        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
998        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
999        does: it's just the validity check that is more restrictive.
1001    16. Inserted checks for integer overflows during escape sequence (backslash)
1002        processing, and also fixed erroneous offset values for syntax errors during
1003        backslash processing.
1005    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1006        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1008    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1009        caused an overrun.
1011    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1012        something other than just ASCII characters) inside a group that had an
1013        unlimited repeat caused a loop at compile time (while checking to see
1014        whether the group could match an empty string).
1016    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1017        [\P{Any}] did so. (Error in the code for printing property names.)
1019    21. An orphan \E inside a character class could cause a crash.
1021    22. A repeated capturing bracket such as (A)? could cause a wild memory
1022        reference during compilation.
1024    23. There are several functions in pcre_compile() that scan along a compiled
1025        expression for various reasons (e.g. to see if it's fixed length for look
1026        behind). There were bugs in these functions when a repeated \p or \P was
1027        present in the pattern. These operators have additional parameters compared
1028        with \d, etc, and these were not being taken into account when moving along
1029        the compiled data. Specifically:
1031        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1032            length.
1034        (b) An item such as \pL+ within a repeated group could cause crashes or
1035            loops.
1037        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1038            "reference to non-existent subpattern" error.
1040        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1042    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1043        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1045    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1047    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1048        character were causing crashes (broken optimization).
1050    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1051        \p or \P) caused a compile-time loop.
1053    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1054        break. For example, the unstudied pattern [\r\n]A does not match the string
1055        "\r\nA" because change 7.0/46 below moves the current point on by two
1056        characters after failing to match at the start. However, the pattern \nA
1057        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1058        the same is true. There doesn't seem any very clean way out of this, but
1059        what I have chosen to do makes the common cases work: PCRE now takes note
1060        of whether there can be an explicit match for \r or \n anywhere in the
1061        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1062        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1063        pattern has explicit CR or LF references.
1065    29. Added (*CR) etc for changing newline setting at start of pattern.
1068    Version 7.2 19-Jun-07
1069    ---------------------
1071     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1072        which is apparently normally available under Windows.
1074     2. Re-jig the pcregrep tests with different newline settings in an attempt
1075        to make them independent of the local environment's newline setting.
1077     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1079     4. Some of the "internals" tests were previously cut out when the link size
1080        was not 2, because the output contained actual offsets. The recent new
1081        "Z" feature of pcretest means that these can be cut out, making the tests
1082        usable with all link sizes.
1084     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1085        stack recursion. This gives a massive performance boost under BSD, but just
1086        a small improvement under Linux. However, it saves one field in the frame
1087        in all cases.
1089     6. Added more features from the forthcoming Perl 5.10:
1091        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1092            recursion call. It refers to the nth most recently opened parentheses.
1094        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1095            to be opened parentheses.
1097        (c) Conditions that refer to capturing parentheses can be specified
1098            relatively, for example, (?(-2)... or (?(+3)...
1100        (d) \K resets the start of the current match so that everything before
1101            is not part of it.
1103        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1105        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1106            reference syntax.
1108        (g) (?| introduces a group in which the numbering of parentheses in each
1109            alternative starts with the same number.
1111        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1113     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1116     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1117        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1118        for detecting groups that can match an empty string.
1120     9. A pattern with a very large number of alternatives (more than several
1121        hundred) was running out of internal workspace during the pre-compile
1122        phase, where pcre_compile() figures out how much memory will be needed. A
1123        bit of new cunning has reduced the workspace needed for groups with
1124        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1125        workspace instead of running out of the 4096 that are available.
1127    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1129    11. Applied patch from Google to remove an optimization that didn't quite work.
1130        The report of the bug said:
1132          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1133          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1134          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1136    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1137        it matched the wrong number of bytes.
1140    Version 7.1 24-Apr-07
1141    ---------------------
1143     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1144        that is more "standard", making use of automake and other Autotools. There
1145        is some re-arrangement of the files and adjustment of comments consequent
1146        on this.
1148     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1149        for recursive directory scanning broke on some systems because the files
1150        are not scanned in any specific order and on different systems the order
1151        was different. A call to "sort" has been inserted into RunGrepTest for the
1152        approprate test as a short-term fix. In the longer term there may be an
1153        alternative.
1155     3. I had an email from Eric Raymond about problems translating some of PCRE's
1156        man pages to HTML (despite the fact that I distribute HTML pages, some
1157        people do their own conversions for various reasons). The problems
1158        concerned the use of low-level troff macros .br and .in. I have therefore
1159        removed all such uses from the man pages (some were redundant, some could
1160        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1161        HTML has been updated to handle .nf/.fi and to complain if it encounters
1162        .br or .in.
1164     4. Updated comments in configure.ac that get placed in config.h.in and also
1165        arranged for config.h to be included in the distribution, with the name
1166        config.h.generic, for the benefit of those who have to compile without
1167        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1169     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1170        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1171        makevp.bat for the current PCRE, using the additional files
1172        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1174     6. A Windows user reported a minor discrepancy with test 2, which turned out
1175        to be caused by a trailing space on an input line that had got lost in his
1176        copy. The trailing space was an accident, so I've just removed it.
1178     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1179        that is needed.
1181     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1182        as "const" (a) because they are and (b) because it helps the PHP
1183        maintainers who have recently made a script to detect big data structures
1184        in the php code that should be moved to the .rodata section. I remembered
1185        to update Builducptable as well, so it won't revert if ucptable.h is ever
1186        re-created.
1188     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1189        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1190        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1191        support is not required. This saves 1.5-2K of code, which is important in
1192        some applications.
1194        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1195        so as not to refer to the tables, even though these functions will never be
1196        called when UTF-8 support is disabled. Otherwise there are problems with a
1197        shared library.
1199    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1201        (a) It was defining its arguments as char * instead of void *.
1203        (b) It was assuming that all moves were upwards in memory; this was true
1204            a long time ago when I wrote it, but is no longer the case.
1206        The emulated memove() is provided for those environments that have neither
1207        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1208        is clearly not the case, as these two bugs were recently reported.
1210    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1211        and Detrail to create the HTML documentation, the .txt form of the man
1212        pages, and it removes trailing spaces from listed files. It also creates
1213        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1214        case, it wraps all the #defines with #ifndefs. This script should be run
1215        before "make dist".
1217    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1218        with Unicode property support.
1220        (a) For a maximizing quantifier, if the two different cases of the
1221            character were of different lengths in their UTF-8 codings (there are
1222            some cases like this - I found 11), and the matching function had to
1223            back up over a mixture of the two cases, it incorrectly assumed they
1224            were both the same length.
1226        (b) When PCRE was configured to use the heap rather than the stack for
1227            recursion during matching, it was not correctly preserving the data for
1228            the other case of a UTF-8 character when checking ahead for a match
1229            while processing a minimizing repeat. If the check also involved
1230            matching a wide character, but failed, corruption could cause an
1231            erroneous result when trying to check for a repeat of the original
1232            character.
1234    13. Some tidying changes to the testing mechanism:
1236        (a) The RunTest script now detects the internal link size and whether there
1237            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1238            values substituted by "configure". (The RunGrepTest script already did
1239            this for UTF-8.) The configure.ac script no longer substitutes the
1240            relevant variables.
1242        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1243            with length and offset values. This means that the output is different
1244            for different internal link sizes. Test 2 is skipped for link sizes
1245            other than 2 because of this, bypassing the problem. Unfortunately,
1246            there was also a test in test 3 (the locale tests) that used /B and
1247            failed for link sizes other than 2. Rather than cut the whole test out,
1248            I have added a new /Z option to pcretest that replaces the length and
1249            offset values with spaces. This is now used to make test 3 independent
1250            of link size. (Test 2 will be tidied up later.)
1252    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1253        segmentation fault instead of returning the appropriate error message.
1255    15. In multiline mode when the newline sequence was set to "any", the pattern
1256        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1257        This doesn't seem right; it now treats the CRLF combination as the line
1258        ending, and so does not match in that case. It's only a pattern such as ^$
1259        that would hit this one: something like ^ABC$ would have failed after \r
1260        and then tried again after \r\n.
1262    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1263        in an attempt to make files that differ only in their line terminators
1264        compare equal. This works on Linux.
1266    17. Under certain error circumstances pcregrep might try to free random memory
1267        as it exited. This is now fixed, thanks to valgrind.
1269    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1270        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1271        was because its rules for how to advance for /g after matching an empty
1272        string at the end of a line did not allow for this case. They now check for
1273        it specially.
1275    20. pcretest is supposed to handle patterns and data of any length, by
1276        extending its buffers when necessary. It was getting this wrong when the
1277        buffer for a data line had to be extended.
1279    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1280        CRLF as a newline sequence.
1282    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1283        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1284        I have nevertheless tidied it up.
1286    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1288    24. Added a man page for pcre-config.
1291    Version 7.0 19-Dec-06
1292    ---------------------
1294     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1295        moving to gcc 4.1.1.
1297     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1298        sys/time.h, which is documented as needed for this function. It doesn't
1299        seem to matter on Linux, but it showed up on some releases of OS X.
1301     3. It seems that there are systems where bytes whose values are greater than
1302        127 match isprint() in the "C" locale. The "C" locale should be the
1303        default when a C program starts up. In most systems, only ASCII printing
1304        characters match isprint(). This difference caused the output from pcretest
1305        to vary, making some of the tests fail. I have changed pcretest so that:
1307        (a) When it is outputting text in the compiled version of a pattern, bytes
1308            other than 32-126 are always shown as hex escapes.
1310        (b) When it is outputting text that is a matched part of a subject string,
1311            it does the same, unless a different locale has been set for the match
1312            (using the /L modifier). In this case, it uses isprint() to decide.
1314     4. Fixed a major bug that caused incorrect computation of the amount of memory
1315        required for a compiled pattern when options that changed within the
1316        pattern affected the logic of the preliminary scan that determines the
1317        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1318        that the computed length was too small. The symptoms of this bug were
1319        either the PCRE error "internal error: code overflow" from pcre_compile(),
1320        or a glibc crash with a message such as "pcretest: free(): invalid next
1321        size (fast)". Examples of patterns that provoked this bug (shown in
1322        pcretest format) are:
1324          /(?-x: )/x
1325          /(?x)(?-x: \s*#\s*)/
1326          /((?i)[\x{c0}])/8
1327          /(?i:[\x{c0}])/8
1329        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1330        is now done differently.
1332     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1333        wrapper classes; (b) implement a new function in the C++ scanner that is
1334        more efficient than the old way of doing things because it avoids levels of
1335        recursion in the regex matching; (c) add a paragraph to the documentation
1336        for the FullMatch() function.
1338     6. The escape sequence \n was being treated as whatever was defined as
1339        "newline". Not only was this contrary to the documentation, which states
1340        that \n is character 10 (hex 0A), but it also went horribly wrong when
1341        "newline" was defined as CRLF. This has been fixed.
1343     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1344        was being set to -1 for the "end of line" case (supposedly a value that no
1345        character can have). Though this value is never used (the check for end of
1346        line is "zero bytes in current character"), it caused compiler complaints.
1347        I've changed it to 0xffffffff.
1349     8. In pcre_version.c, the version string was being built by a sequence of
1350        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1351        string (as it is for production releases) called a macro with an empty
1352        argument. The C standard says the result of this is undefined. The gcc
1353        compiler treats it as an empty string (which was what was wanted) but it is
1354        reported that Visual C gives an error. The source has been hacked around to
1355        avoid this problem.
1357     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1358        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1359        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1360        of them did).
1362    10. Originally, pcretest opened its input and output without "b"; then I was
1363        told that "b" was needed in some environments, so it was added for release
1364        5.0 to both the input and output. (It makes no difference on Unix-like
1365        systems.) Later I was told that it is wrong for the input on Windows. I've
1366        now abstracted the modes into two macros, to make it easier to fiddle with
1367        them, and removed "b" from the input mode under Windows.
1369    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1371    12. Added -help and --help to pcretest as an official way of being reminded
1372        of the options.
1374    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1375        and pcrecpp.cc because they annoy compilers at high warning levels.
1377    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1379    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1380        scripts are not C programs :-) and which was not noticed because it works
1381        on Linux.
1383    16. pcretest is supposed to handle any length of pattern and data line (as one
1384        line or as a continued sequence of lines) by extending its input buffer if
1385        necessary. This feature was broken for very long pattern lines, leading to
1386        a string of junk being passed to pcre_compile() if the pattern was longer
1387        than about 50K.
1389    17. I have done a major re-factoring of the way pcre_compile() computes the
1390        amount of memory needed for a compiled pattern. Previously, there was code
1391        that made a preliminary scan of the pattern in order to do this. That was
1392        OK when PCRE was new, but as the facilities have expanded, it has become
1393        harder and harder to keep it in step with the real compile phase, and there
1394        have been a number of bugs (see for example, 4 above). I have now found a
1395        cunning way of running the real compile function in a "fake" mode that
1396        enables it to compute how much memory it would need, while actually only
1397        ever using a few hundred bytes of working memory and without too many
1398        tests of the mode. This should make future maintenance and development
1399        easier. A side effect of this work is that the limit of 200 on the nesting
1400        depth of parentheses has been removed (though this was never a serious
1401        limitation, I suspect). However, there is a downside: pcre_compile() now
1402        runs more slowly than before (30% or more, depending on the pattern). I
1403        hope this isn't a big issue. There is no effect on runtime performance.
1405    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1406        newline (only possible for the last line of a file) and it was a
1407        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1409    19. Added additional timing features to pcretest. (1) The -tm option now times
1410        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1411        separate command line item, by a number that specifies the number of
1412        repeats to use when timing. The default is 50000; this gives better
1413        precision, but takes uncomfortably long for very large patterns.
1415    20. Extended pcre_study() to be more clever in cases where a branch of a
1416        subpattern has no definite first character. For example, (a*|b*)[cd] would
1417        previously give no result from pcre_study(). Now it recognizes that the
1418        first character must be a, b, c, or d.
1420    21. There was an incorrect error "recursive call could loop indefinitely" if
1421        a subpattern (or the entire pattern) that was being tested for matching an
1422        empty string contained only one non-empty item after a nested subpattern.
1423        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1424        incorrectly, because the \d was being skipped in the check.
1426    22. The pcretest program now has a new pattern option /B and a command line
1427        option -b, which is equivalent to adding /B to every pattern. This causes
1428        it to show the compiled bytecode, without the additional information that
1429        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1430        is the same as /B/I).
1432    23. A new optimization is now able automatically to treat some sequences such
1433        as a*b as a*+b. More specifically, if something simple (such as a character
1434        or a simple class like \d) has an unlimited quantifier, and is followed by
1435        something that cannot possibly match the quantified thing, the quantifier
1436        is automatically "possessified".
1438    24. A recursive reference to a subpattern whose number was greater than 39
1439        went wrong under certain circumstances in UTF-8 mode. This bug could also
1440        have affected the operation of pcre_study().
1442    25. Realized that a little bit of performance could be had by replacing
1443        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1445    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1447    27. Possessive quantifiers such as a++ were previously implemented by turning
1448        them into atomic groups such as ($>a+). Now they have their own opcodes,
1449        which improves performance. This includes the automatically created ones
1450        from 23 above.
1452    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1453        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1454        the first matched character to be a colon. This applied both to named and
1455        numbered groups.
1457    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1459    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1460        building PCRE on Windows easier, so I have included it in the distribution.
1462    31. There is now a check in pcretest against a ridiculously large number being
1463        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1464        loop, the loop is abandoned.
1466    32. Forward references to subpatterns in conditions such as (?(2)...) where
1467        subpattern 2 is defined later cause pcre_compile() to search forwards in
1468        the pattern for the relevant set of parentheses. This search went wrong
1469        when there were unescaped parentheses in a character class, parentheses
1470        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1472    33. "Subroutine" calls and backreferences were previously restricted to
1473        referencing subpatterns earlier in the regex. This restriction has now
1474        been removed.
1476    34. Added a number of extra features that are going to be in Perl 5.10. On the
1477        whole, these are just syntactic alternatives for features that PCRE had
1478        previously implemented using the Python syntax or my own invention. The
1479        other formats are all retained for compatibility.
1481        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1482            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1483            also .NET compatible.
1485        (b) A recursion or subroutine call to a named group can now be defined as
1486            (?&name) as well as (?P>name).
1488        (c) A backreference to a named group can now be defined as \k<name> or
1489            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1490            5.10, are also .NET compatible.
1492        (d) A conditional reference to a named group can now use the syntax
1493            (?(<name>) or (?('name') as well as (?(name).
1495        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1496            groups (named and numbered) that are never evaluated inline, but can be
1497            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1498            is always false. There may be only one alternative in such a group.
1500        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1501            as the simple (?(R). The condition is true only if the most recent
1502            recursion is that of the given number or name. It does not search out
1503            through the entire recursion stack.
1505        (g) The escape \gN or \g{N} has been added, where N is a positive or
1506            negative number, specifying an absolute or relative reference.
1508    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1509        some "unreachable code" warnings.
1511    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1512        things, this adds five new scripts.
1514    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1515        There were also incompatibilities regarding the handling of \Q..\E inside
1516        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1517        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1519    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1520        matches an empty string, and forcibly breaks the loop. There were bugs in
1521        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1522        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1523        separate and independent bugs (that affected different cases) have been
1524        fixed.
1526    39. Refactored the code to abolish the use of different opcodes for small
1527        capturing bracket numbers. This is a tidy that I avoided doing when I
1528        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1529        The new approach is not only tidier, it makes it possible to reduce the
1530        memory needed to fix the previous bug (38).
1532    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1533        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1534        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1535        mode.
1537    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1538        report.
1540    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1541        copy construction and assignment in the C++ wrapper.
1543    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1544        couple of bugs that could have given wrong results in the "--newline=crlf"
1545        case.
1547    44. Added a number of casts and did some reorganization of signed/unsigned int
1548        variables following suggestions from Dair Grant. Also renamed the variable
1549        "this" as "item" because it is a C++ keyword.
1551    45. Arranged for dftables to add
1553          #include "pcre_internal.h"
1555        to pcre_chartables.c because without it, gcc 4.x may remove the array
1556        definition from the final binary if PCRE is built into a static library and
1557        dead code stripping is activated.
1559    46. For an unanchored pattern, if a match attempt fails at the start of a
1560        newline sequence, and the newline setting is CRLF or ANY, and the next two
1561        characters are CRLF, advance by two characters instead of one.
1564    Version 6.7 04-Jul-06
1565    ---------------------
1567     1. In order to handle tests when input lines are enormously long, pcretest has
1568        been re-factored so that it automatically extends its buffers when
1569        necessary. The code is crude, but this _is_ just a test program. The
1570        default size has been increased from 32K to 50K.
1572     2. The code in pcre_study() was using the value of the re argument before
1573        testing it for NULL. (Of course, in any sensible call of the function, it
1574        won't be NULL.)
1576     3. The memmove() emulation function in pcre_internal.h, which is used on
1577        systems that lack both memmove() and bcopy() - that is, hardly ever -
1578        was missing a "static" storage class specifier.
1580     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1581        containing an extended class (one that cannot be represented by a bitmap
1582        because it contains high-valued characters or Unicode property items, e.g.
1583        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1584        pattern, but PCRE should not loop if you do not (it no longer does).
1585        [Detail: two cases were found: (a) a repeated subpattern containing an
1586        extended class; (b) a recursive reference to a subpattern that followed a
1587        previous extended class. It wasn't skipping over the extended class
1588        correctly when UTF-8 mode was not set.]
1590     5. A negated single-character class was not being recognized as fixed-length
1591        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1592        compile error "lookbehind assertion is not fixed length".
1594     6. The RunPerlTest auxiliary script was showing an unexpected difference
1595        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1596        write a Perl script that can interpret lines of an input file either as
1597        byte characters or as UTF-8, which is what "perltest" was being required to
1598        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1599        can't do is switch easily at run time between having the "use utf8;" pragma
1600        or not. In the end, I fudged it by using the RunPerlTest script to insert
1601        "use utf8;" explicitly for the UTF-8 tests.
1603     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1604        the end of the subject string, contrary to the documentation and to what
1605        Perl does. This was true of both matching functions. Now it matches only at
1606        the start of the subject and immediately after *internal* newlines.
1608     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1609        a pointer to an int instead of a pointer to an unsigned long int. This
1610        caused problems on 64-bit systems.
1612     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1613        instance of the 'standard' template library not being so standard".
1615    10. There was no check on the number of named subpatterns nor the maximum
1616        length of a subpattern name. The product of these values is used to compute
1617        the size of the memory block for a compiled pattern. By supplying a very
1618        long subpattern name and a large number of named subpatterns, the size
1619        computation could be caused to overflow. This is now prevented by limiting
1620        the length of names to 32 characters, and the number of named subpatterns
1621        to 10,000.
1623    11. Subpatterns that are repeated with specific counts have to be replicated in
1624        the compiled pattern. The size of memory for this was computed from the
1625        length of the subpattern and the repeat count. The latter is limited to
1626        65535, but there was no limit on the former, meaning that integer overflow
1627        could in principle occur. The compiled length of a repeated subpattern is
1628        now limited to 30,000 bytes in order to prevent this.
1630    12. Added the optional facility to have named substrings with the same name.
1632    13. Added the ability to use a named substring as a condition, using the
1633        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1634        are numbers (not recommended). Forward references are permitted.
1636    14. Added forward references in named backreferences (if you see what I mean).
1638    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1639        pattern could run off the end of the subject. For example, the pattern
1640        "(?s)(.{1,5})"8 did this with the subject "ab".
1642    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1643        PCRE_CASELESS was set when matching characters that were quantified with ?
1644        or *.
1646    17. A character class other than a single negated character that had a minimum
1647        but no maximum quantifier - for example [ab]{6,} - was not handled
1648        correctly by pce_dfa_exec(). It would match only one character.
1650    18. A valid (though odd) pattern that looked like a POSIX character
1651        class but used an invalid character after [ (for example [[,abc,]]) caused
1652        pcre_compile() to give the error "Failed: internal error: code overflow" or
1653        in some cases to crash with a glibc free() error. This could even happen if
1654        the pattern terminated after [[ but there just happened to be a sequence of
1655        letters, a binary zero, and a closing ] in the memory that followed.
1657    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1658        over the years. Originally (before any Unicode support), just the bottom 8
1659        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1660        output from "man perlunicode" includes this:
1662          The regular expression compiler produces polymorphic opcodes.  That
1663          is, the pattern adapts to the data and automatically switches to
1664          the Unicode character scheme when presented with Unicode data--or
1665          instead uses a traditional byte scheme when presented with byte
1666          data.
1668        Sadly, a wide octal escape does not cause a switch, and in a string with
1669        no other multibyte characters, these octal escapes are treated as before.
1670        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1671        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1672        Unicode string.
1674        I have not perpetrated such confusion in PCRE. Up till now, it took just
1675        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1676        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1677        translate to the appropriate multibyte character.
1679    29. Applied some refactoring to reduce the number of warnings from Microsoft
1680        and Borland compilers. This has included removing the fudge introduced
1681        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1682        a warning about an unused variable.
1684    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1685        characters since release 4.0, because Perl (from release 5.004) does not.
1686        [Or at least, is documented not to: some releases seem to be in conflict
1687        with the documentation.] However, when a pattern was studied with
1688        pcre_study() and all its branches started with \s, PCRE still included VT
1689        as a possible starting character. Of course, this did no harm; it just
1690        caused an unnecessary match attempt.
1692    22. Removed a now-redundant internal flag bit that recorded the fact that case
1693        dependency changed within the pattern. This was once needed for "required
1694        byte" processing, but is no longer used. This recovers a now-scarce options
1695        bit. Also moved the least significant internal flag bit to the most-
1696        significant bit of the word, which was not previously used (hangover from
1697        the days when it was an int rather than a uint) to free up another bit for
1698        the future.
1700    23. Added support for CRLF line endings as well as CR and LF. As well as the
1701        default being selectable at build time, it can now be changed at runtime
1702        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1703        specify that it is scanning data with non-default line endings.
1705    24. Changed the definition of CXXLINK to make it agree with the definition of
1706        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1708    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1709        recursions. This makes a big different to stack usage for some patterns.
1711    26. If a subpattern containing a named recursion or subroutine reference such
1712        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1713        the space required for the compiled pattern went wrong and gave too small a
1714        value. Depending on the environment, this could lead to "Failed: internal
1715        error: code overflow at offset 49" or "glibc detected double free or
1716        corruption" errors.
1718    27. Applied patches from Google (a) to support the new newline modes and (b) to
1719        advance over multibyte UTF-8 characters in GlobalReplace.
1721    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1722        difference for some implementation of PCRE in some Windows version.
1724    29. Added some extra testing facilities to pcretest:
1726        \q<number>   in a data line sets the "match limit" value
1727        \Q<number>   in a data line sets the "match recursion limt" value
1728        -S <number>  sets the stack size, where <number> is in megabytes
1730        The -S option isn't available for Windows.
1733    Version 6.6 06-Feb-06
1734    ---------------------
1736     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1737        in pcreposix.h. I have copied the definition from pcre.h.
1739     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1740        because pcre.h is no longer a built file.
1742     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1743        not normally included in the compiled code.
1746    Version 6.5 01-Feb-06
1747    ---------------------
1749     1. When using the partial match feature with pcre_dfa_exec(), it was not
1750        anchoring the second and subsequent partial matches at the new starting
1751        point. This could lead to incorrect results. For example, with the pattern
1752        /1234/, partially matching against "123" and then "a4" gave a match.
1754     2. Changes to pcregrep:
1756        (a) All non-match returns from pcre_exec() were being treated as failures
1757            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1758            error message is output. Some extra information is given for the
1759            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1760            probably the only errors that are likely to be caused by users (by
1761            specifying a regex that has nested indefinite repeats, for instance).
1762            If there are more than 20 of these errors, pcregrep is abandoned.
1764        (b) A binary zero was treated as data while matching, but terminated the
1765            output line if it was written out. This has been fixed: binary zeroes
1766            are now no different to any other data bytes.
1768        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1769            used to set a locale for matching. The --locale=xxxx long option has
1770            been added (no short equivalent) to specify a locale explicitly on the
1771            pcregrep command, overriding the environment variables.
1773        (d) When -B was used with -n, some line numbers in the output were one less
1774            than they should have been.
1776        (e) Added the -o (--only-matching) option.
1778        (f) If -A or -C was used with -c (count only), some lines of context were
1779            accidentally printed for the final match.
1781        (g) Added the -H (--with-filename) option.
1783        (h) The combination of options -rh failed to suppress file names for files
1784            that were found from directory arguments.
1786        (i) Added the -D (--devices) and -d (--directories) options.
1788        (j) Added the -F (--fixed-strings) option.
1790        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1792        (l) Added the --colo(u)r option.
1794        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1795            is not present by default.
1797     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1798        items such as (?R) or (?1), when the recursion could match a number of
1799        alternatives. If it matched one of the alternatives, but subsequently,
1800        outside the recursion, there was a failure, the code tried to back up into
1801        the recursion. However, because of the way PCRE is implemented, this is not
1802        possible, and the result was an incorrect result from the match.
1804        In order to prevent this happening, the specification of recursion has
1805        been changed so that all such subpatterns are automatically treated as
1806        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1808     4. I had overlooked the fact that, in some locales, there are characters for
1809        which isalpha() is true but neither isupper() nor islower() are true. In
1810        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1811        and ordfeminine) are like this. This affected the treatment of \w and \W
1812        when they appeared in character classes, but not when they appeared outside
1813        a character class. The bit map for "word" characters is now created
1814        separately from the results of isalnum() instead of just taking it from the
1815        upper, lower, and digit maps. (Plus the underscore character, of course.)
1817     5. The above bug also affected the handling of POSIX character classes such as
1818        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1819        permanent tables. Instead, the bit maps for such a class were previously
1820        created as the appropriate unions of the upper, lower, and digit bitmaps.
1821        Now they are created by subtraction from the [[:word:]] class, which has
1822        its own bitmap.
1824     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1825        It is created by subtracting the vertical space characters (\x09, \x0a,
1826        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1827        subtraction was done in the overall bitmap for a character class, meaning
1828        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1829        be recognized. This bug has been fixed.
1831     7. Patches from the folks at Google:
1833          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1834          real life, but is still worth protecting against".
1836          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1837          regular expressions".
1839          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1840          have it.
1842          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1843          "configure" and the latter not, in order to fix a problem somebody had
1844          with compiling the Arg class on HP-UX.
1846          (e) Improve the error-handling of the C++ wrapper a little bit.
1848          (f) New tests for checking recursion limiting.
1850     8. The pcre_memmove() function, which is used only if the environment does not
1851        have a standard memmove() function (and is therefore rarely compiled),
1852        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1853        returning a result (though PCRE never actually uses the result).
1855     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1856        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1857        returned instead of calling malloc() with an overflowing number that would
1858        most likely cause subsequent chaos.
1860    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1862    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1863        with this option is matched, the nmatch and pmatch options of regexec() are
1864        ignored.
1866    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1867        provided in case anyone wants to the the POSIX interface with UTF-8
1868        strings.
1870    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1871        C++ linking (needed for some HP-UX environments).
1873    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1874        (unused parameter) and in the pcre_printint() function (omitted "default"
1875        switch label when the default is to do nothing).
1877    15. Added some code to make it possible, when PCRE is compiled as a C++
1878        library, to replace subject pointers for pcre_exec() with a smart pointer
1879        class, thus making it possible to process discontinuous strings.
1881    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1882        much the same function. They were added by different people who were trying
1883        to make PCRE easy to compile on non-Unix systems. It has been suggested
1884        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1885        for compiling on Windows systems. I have therefore replaced it with
1886        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1887        defaults to "extern" for C or "extern C" for C++, which works fine on
1888        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1889        SCOPE with something explicit in config.h. In addition:
1891        (a) pcreposix.h still had just "extern" instead of either of these macros;
1892            I have replaced it with PCRE_DATA_SCOPE.
1894        (b) Functions such as _pcre_xclass(), which are internal to the library,
1895            but external in the C sense, all had PCRE_EXPORT in their definitions.
1896            This is apparently wrong for the Windows case, so I have removed it.
1897            (It makes no difference on Unix-like systems.)
1899    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1900        of recursive calls to match(). This is different to MATCH_LIMIT because
1901        that limits the total number of calls to match(), not all of which increase
1902        the depth of recursion. Limiting the recursion depth limits the amount of
1903        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1904        when PCRE is compiled, and changed at run time. A patch from Google adds
1905        this functionality to the C++ interface.
1907    18. Changes to the handling of Unicode character properties:
1909        (a) Updated the table to Unicode 4.1.0.
1911        (b) Recognize characters that are not in the table as "Cn" (undefined).
1913        (c) I revised the way the table is implemented to a much improved format
1914            which includes recognition of ranges. It now supports the ranges that
1915            are defined in UnicodeData.txt, and it also amalgamates other
1916            characters into ranges. This has reduced the number of entries in the
1917            table from around 16,000 to around 3,000, thus reducing its size
1918            considerably. I realized I did not need to use a tree structure after
1919            all - a binary chop search is just as efficient. Having reduced the
1920            number of entries, I extended their size from 6 bytes to 8 bytes to
1921            allow for more data.
1923        (d) Added support for Unicode script names via properties such as \p{Han}.
1925    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1926        matching that character.
1928    20. When matching a repeated Unicode property with a minimum greater than zero,
1929        (for example \pL{2,}), PCRE could look past the end of the subject if it
1930        reached it while seeking the minimum number of characters. This could
1931        happen only if some of the characters were more than one byte long, because
1932        there is a check for at least the minimum number of bytes.
1934    21. Refactored the implementation of \p and \P so as to be more general, to
1935        allow for more different types of property in future. This has changed the
1936        compiled form incompatibly. Anybody with saved compiled patterns that use
1937        \p or \P will have to recompile them.
1939    22. Added "Any" and "L&" to the supported property types.
1941    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1942        but give a compile time error if the value is greater than 0xff.
1944    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1945        accidentally not being installed or uninstalled.
1947    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1948        made were to insert the current release number. This seemed silly, because
1949        it made things harder for people building PCRE on systems that don't run
1950        "configure". I have turned pcre.h into a distributed file, no longer built
1951        by "configure", with the version identification directly included. There is
1952        no longer a pcre.h.in file.
1954        However, this change necessitated a change to the pcre-config script as
1955        well. It is built from pcre-config.in, and one of the substitutions was the
1956        release number. I have updated configure.ac so that ./configure now finds
1957        the release number by grepping pcre.h.
1959    26. Added the ability to run the tests under valgrind.
1962    Version 6.4 05-Sep-05
1963    ---------------------
1965     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1966        "--" to be printed when multiple files were scanned, even when none of the
1967        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1968        consider it to be a bug, and have restored the previous behaviour.
1970     2. A couple of code tidies to get rid of compiler warnings.
1972     3. The pcretest program used to cheat by referring to symbols in the library
1973        whose names begin with _pcre_. These are internal symbols that are not
1974        really supposed to be visible externally, and in some environments it is
1975        possible to suppress them. The cheating is now confined to including
1976        certain files from the library's source, which is a bit cleaner.
1978     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1979        file's purpose clearer.
1981     5. Reorganized pcre_ucp_findchar().
1984    Version 6.3 15-Aug-05
1985    ---------------------
1987     1. The file libpcre.pc.in did not have general read permission in the tarball.
1989     2. There were some problems when building without C++ support:
1991        (a) If C++ support was not built, "make install" and "make test" still
1992            tried to test it.
1994        (b) There were problems when the value of CXX was explicitly set. Some
1995            changes have been made to try to fix these, and ...
1997        (c) --disable-cpp can now be used to explicitly disable C++ support.
1999        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2000            backslash in a target when C++ was disabled. This confuses some
2001            versions of "make", apparently. Using an intermediate variable solves
2002            this. (Same for CPP_LOBJ.)
2004     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2005        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2006        necessary on certain architectures.
2008     4. Added a setting of -export-symbols-regex to the link command to remove
2009        those symbols that are exported in the C sense, but actually are local
2010        within the library, and not documented. Their names all begin with
2011        "_pcre_". This is not a perfect job, because (a) we have to except some
2012        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2013        available (and never for static libraries). I have made a note to try to
2014        find a way round (a) in the future.
2017    Version 6.2 01-Aug-05
2018    ---------------------
2020     1. There was no test for integer overflow of quantifier values. A construction
2021        such as {1111111111111111} would give undefined results. What is worse, if
2022        a minimum quantifier for a parenthesized subpattern overflowed and became
2023        negative, the calculation of the memory size went wrong. This could have
2024        led to memory overwriting.
2026     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2028     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2029        operating environments where this matters.
2031     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2032        PCRE options from within the C++ wrapper.
2034     5. Named capturing subpatterns were not being correctly counted when a pattern
2035        was compiled. This caused two problems: (a) If there were more than 100
2036        such subpatterns, the calculation of the memory needed for the whole
2037        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2038        back references of the form \12, where the number was greater than 9, were
2039        not recognized as back references, even though there were sufficient
2040        previous subpatterns.
2042     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2043        versions of gcc, e.g. 2.95.4.
2046    Version 6.1 21-Jun-05
2047    ---------------------
2049     1. There was one reference to the variable "posix" in pcretest.c that was not
2050        surrounded by "#if !defined NOPOSIX".
2052     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2053        the cross-check on the old pcre_info() function, for the benefit of the
2054        cut-down version of PCRE that is currently imported into Exim.
2056     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2057        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2058        patterns that start (?i) but I don't think that matters. The use of (?i) is
2059        just an example; this all applies to the other options as well.
2061     4. Since libtool seems to echo the compile commands it is issuing, the output
2062        from "make" can be reduced a bit by putting "@" in front of each libtool
2063        compile command.
2065     5. Patch from the folks at Google for configure.in to be a bit more thorough
2066        in checking for a suitable C++ installation before trying to compile the
2067        C++ stuff. This should fix a reported problem when a compiler was present,
2068        but no suitable headers.
2070     6. The man pages all had just "PCRE" as their title. I have changed them to
2071        be the relevant file name. I have also arranged that these names are
2072        retained in the file doc/pcre.txt, which is a concatenation in text format
2073        of all the man pages except the little individual ones for each function.
2075     7. The NON-UNIX-USE file had not been updated for the different set of source
2076        files that come with release 6. I also added a few comments about the C++
2077        wrapper.
2080    Version 6.0 07-Jun-05
2081    ---------------------
2083     1. Some minor internal re-organization to help with my DFA experiments.
2085     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2086        didn't matter for the library itself when fully configured, but did matter
2087        when compiling without UCP support, or within Exim, where the ucp files are
2088        not imported.
2090     3. Refactoring of the library code to split up the various functions into
2091        different source modules. The addition of the new DFA matching code (see
2092        below) to a single monolithic source would have made it really too
2093        unwieldy, quite apart from causing all the code to be include in a
2094        statically linked application, when only some functions are used. This is
2095        relevant even without the DFA addition now that patterns can be compiled in
2096        one application and matched in another.
2098        The downside of splitting up is that there have to be some external
2099        functions and data tables that are used internally in different modules of
2100        the library but which are not part of the API. These have all had their
2101        names changed to start with "_pcre_" so that they are unlikely to clash
2102        with other external names.
2104     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2105        a different (DFA) algorithm. Although it is slower than the original
2106        function, it does have some advantages for certain types of matching
2107        problem.
2109     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2110        including restarting after a partial match.
2112     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2113        defined when compiling for Windows was sent to me. I have put it into the
2114        code, though I have no means of testing or verifying it.
2116     7. Added the pcre_refcount() auxiliary function.
2118     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2119        match before or at the first newline in the subject string. In pcretest,
2120        the /f option on a pattern can be used to set this.
2122     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2123        would behave wrongly. This has been present in PCRE since release 4.0.
2125    10. A number of changes to the pcregrep command:
2127        (a) Refactored how -x works; insert ^(...)$ instead of setting
2128            PCRE_ANCHORED and checking the length, in preparation for adding
2129            something similar for -w.
2131        (b) Added the -w (match as a word) option.
2133        (c) Refactored the way lines are read and buffered so as to have more
2134            than one at a time available.
2136        (d) Implemented a pcregrep test script.
2138        (e) Added the -M (multiline match) option. This allows patterns to match
2139            over several lines of the subject. The buffering ensures that at least
2140            8K, or the rest of the document (whichever is the shorter) is available
2141            for matching (and similarly the previous 8K for lookbehind assertions).
2143        (f) Changed the --help output so that it now says
2145              -w, --word-regex(p)
2147            instead of two lines, one with "regex" and the other with "regexp"
2148            because that confused at least one person since the short forms are the
2149            same. (This required a bit of code, as the output is generated
2150            automatically from a table. It wasn't just a text change.)
2152        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2153            option but starts with a hyphen. Could be a pattern or a path name
2154            starting with a hyphen, for instance.
2156        (h) "-" can be given as a file name to represent stdin.
2158        (i) When file names are being printed, "(standard input)" is used for
2159            the standard input, for compatibility with GNU grep. Previously
2160            "<stdin>" was used.
2162        (j) The option --label=xxx can be used to supply a name to be used for
2163            stdin when file names are being printed. There is no short form.
2165        (k) Re-factored the options decoding logic because we are going to add
2166            two more options that take data. Such options can now be given in four
2167            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2169        (l) Added the -A, -B, and -C options for requesting that lines of context
2170            around matches be printed.
2172        (m) Added the -L option to print the names of files that do not contain
2173            any matching lines, that is, the complement of -l.
2175        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2176            continue to scan other files.
2178        (o) The -s option was incorrectly implemented. For compatibility with other
2179            greps, it now suppresses the error message for a non-existent or non-
2180            accessible file (but not the return code). There is a new option called
2181            -q that suppresses the output of matching lines, which was what -s was
2182            previously doing.
2184        (p) Added --include and --exclude options to specify files for inclusion
2185            and exclusion when recursing.
2187    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2188        Hopefully, it now does.
2190    12. Missing cast in pcre_study().
2192    13. Added an "uninstall" target to the makefile.
2194    14. Replaced "extern" in the function prototypes in Makefile.in with
2195        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2196        world, but is set differently for Windows.
2198    15. Added a second compiling function called pcre_compile2(). The only
2199        difference is that it has an extra argument, which is a pointer to an
2200        integer error code. When there is a compile-time failure, this is set
2201        non-zero, in addition to the error test pointer being set to point to an
2202        error message. The new argument may be NULL if no error number is required
2203        (but then you may as well call pcre_compile(), which is now just a
2204        wrapper). This facility is provided because some applications need a
2205        numeric error indication, but it has also enabled me to tidy up the way
2206        compile-time errors are handled in the POSIX wrapper.
2208    16. Added VPATH=.libs to the makefile; this should help when building with one
2209        prefix path and installing with another. (Or so I'm told by someone who
2210        knows more about this stuff than I do.)
2212    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2213        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2214        match everything, including newlines. This is not POSIX-compatible, but
2215        somebody wanted the feature. From pcretest it can be activated by using
2216        both the P and the s flags.
2218    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2220    19. libpcre.pc was being incorrectly installed as executable.
2222    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2223        it now also looks for '\r' so that it will work unmodified on Windows.
2225    21. Added Google's contributed C++ wrapper to the distribution.
2227    22. Added some untidy missing memory free() calls in pcretest, to keep
2228        Electric Fence happy when testing.
2232    Version 5.0 13-Sep-04
2233    ---------------------
2235     1. Internal change: literal characters are no longer packed up into items
2236        containing multiple characters in a single byte-string. Each character
2237        is now matched using a separate opcode. However, there may be more than one
2238        byte in the character in UTF-8 mode.
2240     2. The pcre_callout_block structure has two new fields: pattern_position and
2241        next_item_length. These contain the offset in the pattern to the next match
2242        item, and its length, respectively.
2244     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2245        insertion of callouts before each pattern item. Added the /C option to
2246        pcretest to make use of this.
2248     4. On the advice of a Windows user, the lines
2250          #if defined(_WIN32) || defined(WIN32)
2251          _setmode( _fileno( stdout ), 0x8000 );
2252          #endif  /* defined(_WIN32) || defined(WIN32) */
2254        have been added to the source of pcretest. This apparently does useful
2255        magic in relation to line terminators.
2257     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2258        for the benefit of those environments where the "b" makes a difference.
2260     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2261        to know about it. I have put a hack into configure.in that adds in code
2262        to set GCC=yes if CC=icc. This seems to end up at a point in the
2263        generated configure script that is early enough to affect the setting of
2264        compiler options, which is what is needed, but I have no means of testing
2265        whether it really works. (The user who reported this had patched the
2266        generated configure script, which of course I cannot do.)
2268        LATER: After change 22 below (new libtool files), the configure script
2269        seems to know about icc (and also ecc). Therefore, I have commented out
2270        this hack in configure.in.
2272     7. Added support for pkg-config (2 patches were sent in).
2274     8. Negated POSIX character classes that used a combination of internal tables
2275        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2276        [[:^ascii]]. Typically, they would match almost any characters. The other
2277        POSIX classes were not broken in this way.
2279     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2280        to find the match, as PCRE was deluded into thinking that the match had to
2281        start at the start point or following a newline. The same bug applied to
2282        patterns with negative forward assertions or any backward assertions
2283        preceding ".*" at the start, unless the pattern required a fixed first
2284        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2286    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2287        starting at the last subject character, bytes beyond the end of the subject
2288        string were read.
2290    11. Renamed the variable "class" as "classbits" to make life easier for C++
2291        users. (Previously there was a macro definition, but it apparently wasn't
2292        enough.)
2294    12. Added the new field "tables" to the extra data so that tables can be passed
2295        in at exec time, or the internal tables can be re-selected. This allows
2296        a compiled regex to be saved and re-used at a later time by a different
2297        program that might have everything at different addresses.
2299    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2300        -R library as well as a -L library.
2302    14. The debugging options of pcretest (-d on the command line or D on a
2303        pattern) showed incorrect output for anything following an extended class
2304        that contained multibyte characters and which was followed by a quantifier.
2306    15. Added optional support for general category Unicode character properties
2307        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2308        support. It adds about 90K to the size of the library. The meanings of the
2309        inbuilt class escapes such as \d and \s have NOT been changed.
2311    16. Updated pcredemo.c to include calls to free() to release the memory for the
2312        compiled pattern.
2314    17. The generated file chartables.c was being created in the source directory
2315        instead of in the building directory. This caused the build to fail if the
2316        source directory was different from the building directory, and was
2317        read-only.
2319    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2320        file. No doubt somebody will tell me if they don't make sense... Also added
2321        Dan Mooney's comments about building on OpenVMS.
2323    19. Added support for partial matching via the PCRE_PARTIAL option for
2324        pcre_exec() and the \P data escape in pcretest.
2326    20. Extended pcretest with 3 new pattern features:
2328        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2329              write the compiled pattern to the file whose name is "rest-of-line".
2330              This is a straight binary dump of the data, with the saved pointer to
2331              the character tables forced to be NULL. The study data, if any, is
2332              written too. After writing, pcretest reads a new pattern.
2334        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2335              compiled pattern from the given file. There must not be any
2336              occurrences of "<" in the file name (pretty unlikely); if there are,
2337              pcretest will instead treat the initial "<" as a pattern delimiter.
2338              After reading in the pattern, pcretest goes on to read data lines as
2339              usual.
2341        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2342              and 16-bit fields in a compiled pattern, to simulate a pattern that
2343              was compiled on a host of opposite endianness.
2345    21. The pcre-exec() function can now cope with patterns that were compiled on
2346        hosts of opposite endianness, with this restriction:
2348          As for any compiled expression that is saved and used later, the tables
2349          pointer field cannot be preserved; the extra_data field in the arguments
2350          to pcre_exec() should be used to pass in a tables address if a value
2351          other than the default internal tables were used at compile time.
2353    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2354        now diagnosed as an error. Previously, most of the time, a negative number
2355        would have been treated as zero, but if in addition "ovector" was passed as
2356        NULL, a crash could occur.
2358    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2359        new versions from the libtool 1.5 distribution (the last one is a copy of
2360        a file called libtool.m4). This seems to have fixed the need to patch
2361        "configure" to support Darwin 1.3 (which I used to do). However, I still
2362        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2363        workstation).
2365    24. Changed the PCRE licence to be the more standard "BSD" licence.
2368    Version 4.5 01-Dec-03
2369    ---------------------
2371     1. There has been some re-arrangement of the code for the match() function so
2372        that it can be compiled in a version that does not call itself recursively.
2373        Instead, it keeps those local variables that need separate instances for
2374        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2375        needs to "recurse". Keeping track of where control must go is done by means
2376        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2377        hide most of the details from the main code, and operates only if
2378        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2379        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2380        operating.
2382        To make it easier for callers to provide specially tailored get/free
2383        functions for this usage, two new functions, pcre_stack_malloc, and
2384        pcre_stack_free, are used. They are always called in strict stacking order,
2385        and the size of block requested is always the same.
2387        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2388        PCRE has been compiled to use the stack or the heap for recursion. The
2389        -C option of pcretest uses this to show which version is compiled.
2391        A new data escape \S, is added to pcretest; it causes the amounts of store
2392        obtained and freed by both kinds of malloc/free at match time to be added
2393        to the output.
2395     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2396        what's available on my current Linux desktop machine.
2398     3. When matching a UTF-8 string, the test for a valid string at the start has
2399        been extended. If start_offset is not zero, PCRE now checks that it points
2400        to a byte that is the start of a UTF-8 character. If not, it returns
2401        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2402        this is necessary because there may be backward assertions in the pattern.
2403        When matching the same subject several times, it may save resources to use
2404        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2406     4. The code for checking the validity of UTF-8 strings has been tightened so
2407        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2408        containing "overlong sequences".
2410     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2411        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2412        should have been "&", but it just so happened that all the cases this let
2413        through by mistake were picked up later in the function.
2415     6. I had used a variable called "isblank" - this is a C99 function, causing
2416        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2418     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2419        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2420        so the version is shown; (c) stop "make test" echoing "./RunTest".
2422     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2424     9. The prototype for memmove() for systems that don't have it was using
2425        size_t, but the inclusion of the header that defines size_t was later. I've
2426        moved the #includes for the C headers earlier to avoid this.
2428    10. Added some adjustments to the code to make it easier to compiler on certain
2429        special systems:
2431          (a) Some "const" qualifiers were missing.
2432          (b) Added the macro EXPORT before all exported functions; by default this
2433              is defined to be empty.
2434          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2435              that it reads its output file name as an argument instead of writing
2436              to the standard output and assuming this can be redirected.
2438    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2439        class containing characters with values greater than 255, PCRE compilation
2440        went into a loop.
2442    12. A recursive reference to a subpattern that was within another subpattern
2443        that had a minimum quantifier of zero caused PCRE to crash. For example,
2444        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2445        recursion. If the recursively-called subpattern itself had a zero repeat,
2446        that was OK.
2448    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2449        buffer into which it was copied (for escape processing) was still set at
2450        1024, so long lines caused crashes.
2452    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2453        "internal error: code overflow...". This applied to any character class
2454        that was followed by a possessive quantifier.
2456    15. Modified the Makefile to add libpcre.la as a prerequisite for
2457        libpcreposix.la because I was told this is needed for a parallel build to
2458        work.
2460    16. If a pattern that contained .* following optional items at the start was
2461        studied, the wrong optimizing data was generated, leading to matching
2462        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2463        matching string must start with a or b or c. The correct conclusion for
2464        this pattern is that a match can start with any character.
2467    Version 4.4 13-Aug-03
2468    ---------------------
2470     1. In UTF-8 mode, a character class containing characters with values between
2471        127 and 255 was not handled correctly if the compiled pattern was studied.
2472        In fixing this, I have also improved the studying algorithm for such
2473        classes (slightly).
2475     2. Three internal functions had redundant arguments passed to them. Removal
2476        might give a very teeny performance improvement.
2478     3. Documentation bug: the value of the capture_top field in a callout is *one
2479        more than* the number of the hightest numbered captured substring.
2481     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2482        in incorrectly linking with a previously installed version. They now link
2483        explicitly with libpcre.la.
2485     5. configure.in no longer needs to recognize Cygwin specially.
2487     6. A problem in pcre.in for Windows platforms is fixed.
2489     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2490        pcretest, it used to include the size of the study block as part of its
2491        output. Unfortunately, the structure contains a field that has a different
2492        size on different hardware architectures. This meant that the tests that
2493        showed this size failed. As the block is currently always of a fixed size,
2494        this information isn't actually particularly useful in pcretest output, so
2495        I have just removed it.
2497     8. Three pre-processor statements accidentally did not start in column 1.
2498        Sadly, there are *still* compilers around that complain, even though
2499        standard C has not required this for well over a decade. Sigh.
2501     9. In pcretest, the code for checking callouts passed small integers in the
2502        callout_data field, which is a void * field. However, some picky compilers
2503        complained about the casts involved for this on 64-bit systems. Now
2504        pcretest passes the address of the small integer instead, which should get
2505        rid of the warnings.
2507    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2508        both compile and run time, and gives an error if an invalid UTF-8 sequence
2509        is found. There is a option for disabling this check in cases where the
2510        string is known to be correct and/or the maximum performance is wanted.
2512    11. In response to a bug report, I changed one line in Makefile.in from
2514            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2515        to
2516            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2518        to look similar to other lines, but I have no way of telling whether this
2519        is the right thing to do, as I do not use Windows. No doubt I'll get told
2520        if it's wrong...
2523    Version 4.3 21-May-03
2524    ---------------------
2526    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2527       Makefile.
2529    2. Some refactoring to improve the quality of the code:
2531       (i)   The utf8_table... variables are now declared "const".
2533       (ii)  The code for \cx, which used the "case flipping" table to upper case
2534             lower case letters, now just substracts 32. This is ASCII-specific,
2535             but the whole concept of \cx is ASCII-specific, so it seems
2536             reasonable.
2538       (iii) PCRE was using its character types table to recognize decimal and
2539             hexadecimal digits in the pattern. This is silly, because it handles
2540             only 0-9, a-f, and A-F, but the character types table is locale-
2541             specific, which means strange things might happen. A private
2542             table is now used for this - though it costs 256 bytes, a table is
2543             much faster than multiple explicit tests. Of course, the standard
2544             character types table is still used for matching digits in subject
2545             strings against \d.
2547       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2548             ending in _t are). So I've renamed it as ESC_tee.
2550    3. The first argument for regexec() in the POSIX wrapper should have been
2551       defined as "const".
2553    4. Changed pcretest to use malloc() for its buffers so that they can be
2554       Electric Fenced for debugging.
2556    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2557       to read one or more bytes before the start of the subject string. Often this
2558       had no effect on PCRE's behaviour, but in some circumstances it could
2559       provoke a segmentation fault.
2561    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2562       to try to read one or more bytes before the start of the subject string.
2564    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2565       UTF-8 support could misbehave in various ways if the subject string
2566       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2567       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2568       back over UTF-8 characters.)
2571    Version 4.2 14-Apr-03
2572    ---------------------
2574    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2576    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2577         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2578         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2579         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2580         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2581           and BUILD_EXEEXT
2582         Note: automatic setting of the BUILD variables is not yet working
2583         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2584           compile-time but not at link-time
2585         [LINK]: use for linking executables only
2586         make different versions for Windows and non-Windows
2587         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2588           libraries
2589         [LINK_FOR_BUILD]: new variable
2590         [OBJEXT]: use throughout
2591         [EXEEXT]: use throughout
2592         <winshared>: new target
2593         <wininstall>: new target
2594         <dftables.o>: use native compiler
2595         <dftables>: use native linker
2596         <install>: handle Windows platform correctly
2597         <clean>: ditto
2598         <check>: ditto
2599         copy DLL to top builddir before testing
2601       As part of these changes, -no-undefined was removed again. This was reported
2602       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2603       in any case.
2605    3. Some tidies to get rid of compiler warnings:
2607       . In the match_data structure, match_limit was an unsigned long int, whereas
2608         match_call_count was an int. I've made them both unsigned long ints.
2610       . In pcretest the fact that a const uschar * doesn't automatically cast to
2611         a void * provoked a warning.
2613       . Turning on some more compiler warnings threw up some "shadow" variables
2614         and a few more missing casts.
2616    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2617       option, a class that contained a single character with a value between 128
2618       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2620    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2621       option, a class that contained several characters, but with at least one
2622       whose value was between 128 and 255 caused PCRE to crash.
2625    Version 4.1 12-Mar-03
2626    ---------------------
2628    1. Compiling with gcc -pedantic found a couple of places where casts were
2629    needed, and a string in dftables.c that was longer than standard compilers are
2630    required to support.
2632    2. Compiling with Sun's compiler found a few more places where the code could
2633    be tidied up in order to avoid warnings.
2635    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2636    first of these names is deprecated in the latest Autoconf in favour of the name
2637    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2638    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2639    analogy I have changed it to CFLAGS_FOR_BUILD.
2641    4. Added -no-undefined to the linking command in the Makefile, because this is
2642    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2643    linking step for the pcreposix library.
2645    5. PCRE was failing to diagnose the case of two named groups with the same
2646    name.
2648    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2649    literal character that is needed in the subject for a match, and scans along to
2650    ensure that it is present before embarking on the full matching process. This
2651    saves time in cases of nested unlimited repeats that are never going to match.
2652    Problem: the scan can take a lot of time if the subject is very long (e.g.
2653    megabytes), thus penalizing straightforward matches. It is now done only if the
2654    amount of subject to be scanned is less than 1000 bytes.
2656    7. A lesser problem with the same optimization is that it was recording the
2657    first character of an anchored pattern as "needed", thus provoking a search
2658    right along the subject, even when the first match of the pattern was going to
2659    fail. The "needed" character is now not set for anchored patterns, unless it
2660    follows something in the pattern that is of non-fixed length. Thus, it still
2661    fulfils its original purpose of finding quick non-matches in cases of nested
2662    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2665    Version 4.0 17-Feb-03
2666    ---------------------
2668    1. If a comment in an extended regex that started immediately after a meta-item
2669    extended to the end of string, PCRE compiled incorrect data. This could lead to
2670    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2672    2. Moved to autoconf 2.53 and libtool 1.4.2.
2674    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2675    the special perltest8 script is no longer needed - all the tests can be run
2676    from a single perltest script.
2678    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2679    by \s. It has now been removed in PCRE. This means it isn't recognized as
2680    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2681    class [:space:] *does* include VT, thereby creating a mess.
2683    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2684    space and tab.
2686    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2687    its new features into the main test script, reducing the number of scripts.
2689    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2690    were backward compatible, and made the (?i) apply to the whole pattern, as if
2691    /i were given. Now it behaves more logically, and applies the option setting
2692    only to what follows. PCRE has been changed to follow suit. However, if it
2693    finds options settings right at the start of the pattern, it extracts them into
2694    the global options, as before. Thus, they show up in the info data.
2696    8. Added support for the \Q...\E escape sequence. Characters in between are
2697    treated as literals. This is slightly different from Perl in that $ and @ are
2698    also handled as literals inside the quotes. In Perl, they will cause variable
2699    interpolation. Note the following examples:
2701        Pattern            PCRE matches      Perl matches
2703        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2704        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2705        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2707    For compatibility with Perl, \Q...\E sequences are recognized inside character
2708    classes as well as outside them.
2710    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2711    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2712    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2713    signed/unsigned warnings.
2715    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2716    option for pcretest, so I've replaced it by a simple function that does just
2717    that job.
2719    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2720    "pcregrep -".
2722    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2723    Java package. This provides some syntactic sugar for simple cases of what my
2724    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2725    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2726    item, you can use this simplified notation. Note that only makes sense with
2727    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2728    greediness, whatever the setting of the PCRE_UNGREEDY option.
2730    13. A change of greediness default within a pattern was not taking effect at
2731    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2732    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2733    was abstracted outside.
2735    14. PCRE now supports the \G assertion. It is true when the current matching
2736    position is at the start point of the match. This differs from \A when the
2737    starting offset is non-zero. Used with the /g option of pcretest (or similar
2738    code), it works in the same way as it does for Perl's /g option. If all
2739    alternatives of a regex begin with \G, the expression is anchored to the start
2740    match position, and the "anchored" flag is set in the compiled expression.
2742    15. Some bugs concerning the handling of certain option changes within patterns
2743    have been fixed. These applied to options other than (?ims). For example,
2744    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2745    been the other way round. Some of this was related to change 7 above.
2747    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2748    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2749    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2750    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2752    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2753    mode. Unlike ".", it always matches newline, whatever the setting of
2754    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2755    assertions. Perl allows it, but it doesn't (in general) work because it can't
2756    calculate the length of the lookbehind. At least, that's the case for Perl
2757    5.8.0 - I've been told they are going to document that it doesn't work in
2758    future.
2760    18. Added an error diagnosis for escapes that PCRE does not support: these are
2761    \L, \l, \N, \P, \p, \U, \u, and \X.
2763    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2764    reading past the end of the pattern in cases such as /[abcd/.
2766    20. PCRE was getting more memory than necessary for patterns with classes that
2767    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2769    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2770    compiling PCRE for use with Virtual Pascal.
2772    22. Small fix to the Makefile to make it work properly if the build is done
2773    outside the source tree.
2775    23. Added a new extension: a condition to go with recursion. If a conditional
2776    subpattern starts with (?(R) the "true" branch is used if recursion has
2777    happened, whereas the "false" branch is used only at the top level.
2779    24. When there was a very long string of literal characters (over 255 bytes
2780    without UTF support, over 250 bytes with UTF support), the computation of how
2781    much memory was required could be incorrect, leading to segfaults or other
2782    strange effects.
2784    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2785    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2786    there was a subsequent back reference to those brackets. This meant that, for
2787    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2788    possible to check for precisely this case. All we can do is abandon the
2789    optimization if .* occurs inside capturing brackets when there are any back
2790    references whatsoever. (See below for a better fix that came later.)
2792    26. The handling of the optimization for finding the first character of a
2793    non-anchored pattern, and for finding a character that is required later in the
2794    match were failing in some cases. This didn't break the matching; it just
2795    failed to optimize when it could. The way this is done has been re-implemented.
2797    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2799    28. Added a new feature that provides some of the functionality that Perl
2800    provides with (?{...}). The facility is termed a "callout". The way it is done
2801    in PCRE is for the caller to provide an optional function, by setting
2802    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2803    global variable. By default it is unset, which disables all calling out. To get
2804    the function called, the regex must include (?C) at appropriate points. This
2805    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2806    This provides a means of identifying different callout points. When PCRE
2807    reaches such a point in the regex, if pcre_callout has been set, the external
2808    function is called. It is provided with data in a structure called
2809    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2810    matching continues; if it returns a non-zero value, the match at the current
2811    point fails. However, backtracking will occur if possible. [This was changed
2812    later and other features added - see item 49 below.]
2814    29. pcretest is upgraded to test the callout functionality. It provides a
2815    callout function that displays information. By default, it shows the start of
2816    the match and the current position in the text. There are some new data escapes
2817    to vary what happens:
2819        \C+         in addition, show current contents of captured substrings
2820        \C-         do not supply a callout function
2821        \C!n        return 1 when callout number n is reached
2822        \C!n!m      return 1 when callout number n is reached for the mth time
2824    30. If pcregrep was called with the -l option and just a single file name, it
2825    output "<stdin>" if a match was found, instead of the file name.
2827    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2828    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2829    pcre_exec(). This saves a malloc/free per call. The default value of
2830    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2831    when configuring.
2833    32. The default maximum size of a compiled pattern is 64K. There have been a
2834    few cases of people hitting this limit. The code now uses macros to handle the
2835    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2836    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2837    configuring. Tests 2 and 5 work only with 2-byte links because they output
2838    debugging information about compiled patterns.
2840    33. Internal code re-arrangements:
2842    (a) Moved the debugging function for printing out a compiled regex into
2843        its own source file (printint.c) and used #include to pull it into
2844        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2845        separate copies.
2847    (b) Defined the list of op-code names for debugging as a macro in
2848        internal.h so that it is next to the definition of the opcodes.
2850    (c) Defined a table of op-code lengths for simpler skipping along compiled
2851        code. This is again a macro in internal.h so that it is next to the
2852        definition of the opcodes.
2854    34. Added support for recursive calls to individual subpatterns, along the
2855    lines of Robin Houston's patch (but implemented somewhat differently).
2857    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2858    allow it to read and process whole directories in Win32. This code was
2859    contributed by Lionel Fourquaux; it has not been tested by me.
2861    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2862    used to name a group. Names consist of alphanumerics and underscores, and must
2863    be unique. Back references use the syntax (?P=name) and recursive calls use
2864    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2865    numbers. The function pcre_fullinfo() can be used after compilation to extract
2866    a name/number map. There are three relevant calls:
2868      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2869      PCRE_INFO_NAMECOUNT            yields the number of entries
2870      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2872    The map is a vector of fixed-size entries. The size of each entry depends on
2873    the length of the longest name used. The first two bytes of each entry are the
2874    group number, most significant byte first. There follows the corresponding
2875    name, zero terminated. The names are in alphabetical order.
2877    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2878    case instead of 255. Making it the same both with and without UTF-8 support
2879    means that the same test output works with both.
2881    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2882    calling malloc() with a zero argument.
2884    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2885    optimization. I've improved things by keeping a bitmap of backreferences with
2886    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2887    fact referenced, the optimization can be applied. It is unlikely that a
2888    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2889    the match to follow \n) will appear inside brackets with a number greater than
2890    31, but if it does, any back reference > 31 suppresses the optimization.
2892    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2893    of disabling numbered capturing parentheses. Any opening parenthesis that is
2894    not followed by ? behaves as if it were followed by ?: but named parentheses
2895    can still be used for capturing (and they will acquire numbers in the usual
2896    way).
2898    41. Redesigned the return codes from the match() function into yes/no/error so
2899    that errors can be passed back from deep inside the nested calls. A malloc
2900    failure while inside a recursive subpattern call now causes the
2901    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2903    42. It is now possible to set a limit on the number of times the match()
2904    function is called in a call to pcre_exec(). This facility makes it possible to
2905    limit the amount of recursion and backtracking, though not in a directly
2906    obvious way, because the match() function is used in a number of different
2907    circumstances. The count starts from zero for each position in the subject
2908    string (for non-anchored patterns). The default limit is, for compatibility, a
2909    large number, namely 10 000 000. You can change this in two ways:
2911    (a) When configuring PCRE before making, you can use --with-match-limit=n
2912        to set a default value for the compiled library.
2914    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2915        a different value is set. See 45 below.
2917    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2919    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2920    of things that can be changed at compile time. The first argument specifies
2921    what is wanted and the second points to where the information is to be placed.
2922    The current list of available information is:
2924      PCRE_CONFIG_UTF8
2926    The output is an integer that is set to one if UTF-8 support is available;
2927    otherwise it is set to zero.
2931    The output is an integer that it set to the value of the code that is used for
2932    newline. It is either LF (10) or CR (13).
2936    The output is an integer that contains the number of bytes used for internal
2937    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2941    The output is an integer that contains the threshold above which the POSIX
2942    interface uses malloc() for output vectors. See item 31 above.
2946    The output is an unsigned integer that contains the default limit of the number
2947    of match() calls in a pcre_exec() execution. See 42 above.
2949    44. pcretest has been upgraded by the addition of the -C option. This causes it
2950    to extract all the available output from the new pcre_config() function, and to
2951    output it. The program then exits immediately.
2953    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2954    order to support additional features. One way would have been to define
2955    pcre_exec2() (for example) with extra arguments, but this would not have been
2956    extensible, and would also have required all calls to the original function to
2957    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2958    is used for passing in "extra" data from pcre_study().
2960    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2961    contains the following fields:
2963      flags         a bitmap indicating which of the following fields are set
2964      study_data    opaque data from pcre_study()
2965      match_limit   a way of specifying a limit on match() calls for a specific
2966                      call to pcre_exec()
2967      callout_data  data for callouts (see 49 below)
2969    The flag bits are also defined in pcre.h, and are
2975    The pcre_study() function now returns one of these new pcre_extra blocks, with
2976    the actual study data pointed to by the study_data field, and the
2977    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2978    before. That is, this change is entirely upwards-compatible and requires no
2979    change to existing code.
2981    If you want to pass in additional data to pcre_exec(), you can either place it
2982    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2983    block.
2985    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2986    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2987    times with different match limits, until it finds the minimum value needed for
2988    pcre_exec() to complete. The value is then output. This can be instructive; for
2989    most simple matches the number is quite small, but for pathological cases it
2990    gets very large very quickly.
2992    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2993    returns the size of the data block pointed to by the study_data field in a
2994    pcre_extra block, that is, the value that was passed as the argument to
2995    pcre_malloc() when PCRE was getting memory in which to place the information
2996    created by pcre_study(). The fourth argument should point to a size_t variable.
2997    pcretest has been extended so that this information is shown after a successful
2998    pcre_study() call when information about the compiled regex is being displayed.
3000    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3001    because what follows is always an absolute path. (Later: it turns out that this
3002    is more than cosmetic for MinGW, because it doesn't like empty path
3003    components.)
3005    49. Some changes have been made to the callout feature (see 28 above):
3007    (i)  A callout function now has three choices for what it returns:
3009           0  =>  success, carry on matching
3010         > 0  =>  failure at this point, but backtrack if possible
3011         < 0  =>  serious error, return this value from pcre_exec()
3013         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3014         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3015         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3016         use by callout functions. It will never be used by PCRE itself.
3018    (ii) The pcre_extra structure (see 45 above) has a void * field called
3019         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3020         pcre_callout_block structure has a field of the same name. The contents of
3021         the field passed in the pcre_extra structure are passed to the callout
3022         function in the corresponding field in the callout block. This makes it
3023         easier to use the same callout-containing regex from multiple threads. For
3024         testing, the pcretest program has a new data escape
3026           \C*n        pass the number n (may be negative) as callout_data
3028         If the callout function in pcretest receives a non-zero value as
3029         callout_data, it returns that value.
3031    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3032    there were some redundant $(CFLAGS) in commands that are now specified as
3033    $(LINK), which already includes $(CFLAGS).
3035    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3036    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3037    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3038    one-byte characters throughout. Note that case-insensitive matching applies
3039    only to characters whose values are less than 256. PCRE doesn't support the
3040    notion of cases for higher-valued characters.
3042    (i)   A character class whose characters are all within 0-255 is handled as
3043          a bit map, and the map is inverted for negative classes. Previously, a
3044          character > 255 always failed to match such a class; however it should
3045          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3047    (ii)  A negated character class with a single character < 255 is coded as
3048          "not this character" (OP_NOT). This wasn't working properly when the test
3049          character was multibyte, either singly or repeated.
3051    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3052          mode, for example: \x{100}{2,3}.
3054    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3055          singly or repeated) now correctly test multibyte characters. However,
3056          PCRE doesn't recognize any characters with values greater than 255 as
3057          digits, spaces, or word characters. Such characters always match \D, \S,
3058          and \W, and never match \d, \s, or \w.
3060    (v)   Classes may now contain characters and character ranges with values
3061          greater than 255. For example: [ab\x{100}-\x{400}].
3063    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3064          PCRE in UTF-8 mode.
3066    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3067    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3068    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3069    value.)
3071    53. The single man page has become too large. I have therefore split it up into
3072    a number of separate man pages. These also give rise to individual HTML pages;
3073    these are now put in a separate directory, and there is an index.html page that
3074    lists them all. Some hyperlinking between the pages has been installed.
3076    54. Added convenience functions for handling named capturing parentheses.
3078    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3079    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3080    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3081    are faulted.
3083    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3084    calling configure. These values are used when compiling the dftables.c program
3085    which is run to generate the source of the default character tables. They
3086    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3087    you will need to set these values.
3089    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3092    Version 3.9 02-Jan-02
3093    ---------------------
3095    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3097    2. If --disable-static was given, the building process failed when trying to
3098    build pcretest and pcregrep. (For some reason it was using libtool to compile
3099    them, which is not right, as they aren't part of the library.)
3102    Version 3.8 18-Dec-01
3103    ---------------------
3105    1. The experimental UTF-8 code was completely screwed up. It was packing the
3106    bytes in the wrong order. How dumb can you get?
3109    Version 3.7 29-Oct-01
3110    ---------------------
3112    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3113    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3114    this didn't happen under Solaris 8, where I normally test things.
3116    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3117    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3118    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3119    this fix an hour or so after the initial 3.7 release.)
3122    Version 3.6 23-Oct-01
3123    ---------------------
3125    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3126    offsets passed as NULL with zero offset count.
3128    2. The config.guess and config.sub files had not been updated when I moved to
3129    the latest autoconf.
3132    Version 3.5 15-Aug-01
3133    ---------------------
3135    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3136    had been forgotten.
3138    2. By using declared but undefined structures, we can avoid using "void"
3139    definitions in pcre.h while keeping the internal definitions of the structures
3140    private.
3142    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3143    user point of view, this means that both static and shared libraries are built
3144    by default, but this can be individually controlled. More of the work of
3145    handling this static/shared cases is now inside libtool instead of PCRE's make
3146    file.
3148    4. The pcretest utility is now installed along with pcregrep because it is
3149    useful for users (to test regexs) and by doing this, it automatically gets
3150    relinked by libtool. The documentation has been turned into a man page, so
3151    there are now .1, .txt, and .html versions in /doc.
3153    5. Upgrades to pcregrep:
3154       (i)   Added long-form option names like gnu grep.
3155       (ii)  Added --help to list all options with an explanatory phrase.
3156       (iii) Added -r, --recursive to recurse into sub-directories.
3157       (iv)  Added -f, --file to read patterns from a file.
3159    6. pcre_exec() was referring to its "code" argument before testing that
3160    argument for NULL (and giving an error if it was NULL).
3162    7. Upgraded Makefile.in to allow for compiling in a different directory from
3163    the source directory.
3165    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3166    options bits, the pointer it was passed was to an int instead of to an unsigned
3167    long int. This mattered only on 64-bit systems.
3169    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3170    generated) instead of pcre.in, which it its source. Also made the same change
3171    in several of the .c files.
3173    10. A new release of gcc defines printf() as a macro, which broke pcretest
3174    because it had an ifdef in the middle of a string argument for printf(). Fixed
3175    by using separate calls to printf().
3177    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3178    script, to force use of CR or LF instead of \n in the source. On non-Unix
3179    systems, the value can be set in config.h.
3181    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3182    absolute limit. Changed the text of the error message to make this clear, and
3183    likewise updated the man page.
3185    13. The limit of 99 on the number of capturing subpatterns has been removed.
3186    The new limit is 65535, which I hope will not be a "real" limit.
3189    Version 3.4 22-Aug-00
3190    ---------------------
3192    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3194    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3197    Version 3.3 01-Aug-00
3198    ---------------------
3200    1. If an octal character was given, but the value was greater than \377, it
3201    was not getting masked to the least significant bits, as documented. This could
3202    lead to crashes in some systems.
3204    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3205    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3207    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3208    These just pass their arguments on to (pcre_free)(), but they are provided
3209    because some uses of PCRE bind it to non-C systems that can call its functions,
3210    but cannot call free() or pcre_free() directly.
3212    4. Add "make test" as a synonym for "make check". Corrected some comments in
3213    the Makefile.
3215    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3216    Makefile.
3218    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3219    command called pgrep for grepping around the active processes.
3221    7. Added the beginnings of support for UTF-8 character strings.
3223    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3224    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3225    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3226    out for the ar command.)
3229    Version 3.2 12-May-00
3230    ---------------------
3232    This is purely a bug fixing release.
3234    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3235    of ZA. This was just one example of several cases that could provoke this bug,
3236    which was introduced by change 9 of version 2.00. The code for breaking
3237    infinite loops after an iteration that matches an empty string was't working
3238    correctly.
3240    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3241    when matched against abbab (for example). After matching an empty string, it
3242    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3243    caused it to match further down the string than it should.
3245    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3246    was there because it doesn't seem to be needed, and it causes trouble on some
3247    systems, as it is not a Standard C header. It has been removed.
3249    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3250    were reported on the Macintosh. The changes were from
3252      while ((c = *(++ptr)) != 0 && c != '\n');
3253    to
3254      while ((c = *(++ptr)) != 0 && c != '\n') ;
3256    Totally extraordinary, but if that's what it takes...
3258    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3259    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3260    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3261    assumes the way PCRE uses memmove() (always moving upwards).
3263    6. PCRE is being used in one environment where strchr() is not available. There
3264    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3265    faster code anyway.
3268    Version 3.1 09-Feb-00
3269    ---------------------
3271    The only change in this release is the fixing of some bugs in Makefile.in for
3272    the "install" target:
3274    (1) It was failing to install pcreposix.h.
3276    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3279    Version 3.0 01-Feb-00
3280    ---------------------
3282    1. Add support for the /+ modifier to perltest (to output $` like it does in
3283    pcretest).
3285    2. Add support for the /g modifier to perltest.
3287    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3288    matches null strings.
3290    4. Fix perltest so that it doesn't do unwanted things when fed an empty
3291    pattern. Perl treats empty patterns specially - it reuses the most recent
3292    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3293    effect.
3295    5. The POSIX interface was broken in that it was just handing over the POSIX
3296    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3297    required a bigger vector, with some working space on the end. This means that
3298    the POSIX wrapper now has to get and free some memory, and copy the results.
3300    6. Added some simple autoconf support, placing the test data and the
3301    documentation in separate directories, re-organizing some of the
3302    information files, and making it build pcre-config (a GNU standard). Also added
3303    libtool support for building PCRE as a shared library, which is now the
3304    default.
3306    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3307    09 are not valid octal constants. Single digits will be used for minor values
3308    less than 10.
3310    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3311    existing programs that set these in the POSIX interface can use PCRE without
3312    modification.
3314    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3315    return all that pcre_info() returns, plus additional data. The pcre_info()
3316    function is retained for compatibility, but is considered to be obsolete.
3318    10. Added experimental recursion feature (?R) to handle one common case that
3319    Perl 5.6 will be able to do with (?p{...}).
3321    11. Added support for POSIX character classes like [:alpha:], which Perl is
3322    adopting.
3325    Version 2.08 31-Aug-99
3326    ----------------------
3328    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3329    trying to match at the startoffset position, but instead was moving forward to
3330    the next newline as if a previous match had failed.
3332    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3333    and could get into a loop if a null string was matched other than at the start
3334    of the subject.
3336    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3337    be distinguished at compile time, and for completeness also added PCRE_DATE.
3339    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3340    in GnuWin32 environments.
3343    Version 2.07 29-Jul-99
3344    ----------------------
3346    1. The documentation is now supplied in plain text form and HTML as well as in
3347    the form of man page sources.
3349    2. C++ compilers don't like assigning (void *) values to other pointer types.
3350    In particular this affects malloc(). Although there is no problem in Standard
3351    C, I've put in casts to keep C++ compilers happy.
3353    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3354    should be (const char *).
3356    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3357    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3358    However, I haven't made this a standard facility. The documentation doesn't
3359    mention it, and the Makefile doesn't support it.
3361    5. The Makefile now contains an "install" target, with editable destinations at
3362    the top of the file. The pcretest program is not installed.
3364    6. pgrep -V now gives the PCRE version number and date.
3366    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3367    causing the entire string to be ignored, instead of just the last character.
3369    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3370    non-matching string, it can take a very, very long time, even for strings of
3371    quite modest length, because of the nested recursion. PCRE now does better in
3372    some of these cases. It does this by remembering the last required literal
3373    character in the pattern, and pre-searching the subject to ensure it is present
3374    before running the real match. In other words, it applies a heuristic to detect
3375    some types of certain failure quickly, and in the above example, if presented
3376    with a string that has no trailing " it gives "no match" very quickly.
3378    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3379    other alternatives are tried instead.
3382    Version 2.06 09-Jun-99
3383    ----------------------
3385    1. Change pcretest's output for amount of store used to show just the code
3386    space, because the remainder (the data block) varies in size between 32-bit and
3387    64-bit systems.
3389    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3390    start matching at. This allows lookbehinds to work when searching for multiple
3391    occurrences in a string.
3393    3. Added additional options to pcretest for testing multiple occurrences:
3395       /+   outputs the rest of the string that follows a match
3396       /g   loops for multiple occurrences, using the new startoffset argument
3397       /G   loops for multiple occurrences by passing an incremented pointer
3399    4. PCRE wasn't doing the "first character" optimization for patterns starting
3400    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3401    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3402    the letter 'x'. On long subject strings, this gives a significant speed-up.
3405  Version 2.05 21-Apr-99  Version 2.05 21-Apr-99
3406  ----------------------  ----------------------

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