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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.6 19-Jan-08
5    ---------------------
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo.
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
26    4.  A user submitted a patch to Makefile that makes it easy to created a dll
27        under mingw. I added stuff to Makefile.am that cause it to include this
28        special target, without affecting anything else.
30    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
31        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
32        exported in the Windows port". It has not yet been confirmed that the patch
33        solves the problem, but it does no harm.
36    Version 7.5 10-Jan-08
37    ---------------------
39    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
40        values in parens when parsing an RE using the C++ wrapper."
42    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
43        Characters greater than 255 were excluded from the class instead of being
44        included.
46    3.  The same bug as (2) above applied to negated POSIX classes such as
47        [:^space:].
49    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
50        defined or documented. It seems to have been a typo for PCRE_STATIC, so
51        I have changed it.
53    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
54        first named subpattern) and a construct such as (?&a) would reference the
55        first named subpattern whose name started with "a" (in other words, the
56        length check was missing). Both these problems are fixed. "Subpattern name
57        expected" is now given for (?&) (a zero-length name), and this patch also
58        makes it give the same error for \k'' (previously it complained that that
59        was a reference to a non-existent subpattern).
61    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
62        this is right because (?- can be followed by option settings as well as by
63        digits. I have, however, made the messages clearer.
65    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
66        than the number used in the conditional) now cause a compile-time error.
67        This is actually not compatible with Perl, which accepts such patterns, but
68        treats the conditional as always being FALSE (as PCRE used to), but it
69        seems to me that giving a diagnostic is better.
71    8.  Change "alphameric" to the more common word "alphanumeric" in comments
72        and messages.
74    9.  Fix two occurrences of "backslash" in comments that should have been
75        "backspace".
77    10. Remove two redundant lines of code that can never be obeyed (their function
78        was moved elsewhere).
80    11. The program that makes PCRE's Unicode character property table had a bug
81        which caused it to generate incorrect table entries for sequences of
82        characters that have the same character type, but are in different scripts.
83        It amalgamated them into a single range, with the script of the first of
84        them. In other words, some characters were in the wrong script. There were
85        thirteen such cases, affecting characters in the following ranges:
87          U+002b0 - U+002c1
88          U+0060c - U+0060d
89          U+0061e - U+00612
90          U+0064b - U+0065e
91          U+0074d - U+0076d
92          U+01800 - U+01805
93          U+01d00 - U+01d77
94          U+01d9b - U+01dbf
95          U+0200b - U+0200f
96          U+030fc - U+030fe
97          U+03260 - U+0327f
98          U+0fb46 - U+0fbb1
99          U+10450 - U+1049d
101    12. The -o option (show only the matching part of a line) for pcregrep was not
102        compatible with GNU grep in that, if there was more than one match in a
103        line, it showed only the first of them. It now behaves in the same way as
104        GNU grep.
106    13. If the -o and -v options were combined for pcregrep, it printed a blank
107        line for every non-matching line. GNU grep prints nothing, and pcregrep now
108        does the same. The return code can be used to tell if there were any
109        non-matching lines.
111    14. Added --file-offsets and --line-offsets to pcregrep.
113    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
114        infinitely looping recursion. The bug was that positive lookaheads were not
115        being skipped when checking for a possible empty match (negative lookaheads
116        and both kinds of lookbehind were skipped).
118    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
119        inclusion of <windows.h> to before rather than after the definition of
120        INVALID_FILE_ATTRIBUTES (patch from David Byron).
122    17. Specifying a possessive quantifier with a specific limit for a Unicode
123        character property caused pcre_compile() to compile bad code, which led at
124        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
125        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
126        caused the error; without that there was no problem.
128    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
130    19. Added --enable-pcretest-libreadline.
132    20. In pcrecpp.cc, the variable 'count' was incremented twice in
133        RE::GlobalReplace(). As a result, the number of replacements returned was
134        double what it should be. I removed one of the increments, but Craig sent a
135        later patch that removed the other one (the right fix) and added unit tests
136        that check the return values (which was not done before).
138    21. Several CMake things:
140        (1) Arranged that, when cmake is used on Unix, the libraries end up with
141            the names libpcre and libpcreposix, not just pcre and pcreposix.
143        (2) The above change means that pcretest and pcregrep are now correctly
144            linked with the newly-built libraries, not previously installed ones.
148    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
149        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
150        UTF-8 newline character). The key issue is that the pattern starts .*;
151        this means that the match must be either at the beginning, or after a
152        newline. The bug was in the code for advancing after a failed match and
153        checking that the new position followed a newline. It was not taking
154        account of UTF-8 characters correctly.
156    23. PCRE was behaving differently from Perl in the way it recognized POSIX
157        character classes. PCRE was not treating the sequence [:...:] as a
158        character class unless the ... were all letters. Perl, however, seems to
159        allow any characters between [: and :], though of course it rejects as
160        unknown any "names" that contain non-letters, because all the known class
161        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
162        for example, whereas PCRE did not - it did not recognize a POSIX character
163        class. This seemed a bit dangerous, so the code has been changed to be
164        closer to Perl. The behaviour is not identical to Perl, because PCRE will
165        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
166        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
167        Perl does, and where it didn't before.
169    24. Rewrite so as to remove the single use of %n from pcregrep because in some
170        Windows environments %n is disabled by default.
173    Version 7.4 21-Sep-07
174    ---------------------
176    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
177        means that a class such as [\s] counted as "explicit reference to CR or
178        LF". That isn't really right - the whole point of the change was to try to
179        help when there was an actual mention of one of the two characters. So now
180        the change happens only if \r or \n (or a literal CR or LF) character is
181        encountered.
183    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
184        of both had grown to the point where there were only 3 bits left.
185        Fortunately, there was spare space in the data structure, and so I have
186        moved the internal flags into a new 16-bit field to free up more option
187        bits.
189    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
190        but did not set the internal JCHANGED flag - either of these is enough to
191        control the way the "get" function works - but the PCRE_INFO_JCHANGED
192        facility is supposed to tell if (?J) was ever used, so now (?J) at the
193        start sets both bits.
195    4.  Added options (at build time, compile time, exec time) to change \R from
196        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
198    5.  doc/pcresyntax.html was missing from the distribution.
200    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
201        compatibility, even though it is no longer used.
203    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
204        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
205        windows.h file is present (where different names are used). [This was
206        reversed later after testing - see 16 below.]
208    8.  Changed all #include <config.h> to #include "config.h". There were also
209        some further <pcre.h> cases that I changed to "pcre.h".
211    9.  When pcregrep was used with the --colour option, it missed the line ending
212        sequence off the lines that it output.
214    10. It was pointed out to me that arrays of string pointers cause lots of
215        relocations when a shared library is dynamically loaded. A technique of
216        using a single long string with a table of offsets can drastically reduce
217        these. I have refactored PCRE in four places to do this. The result is
218        dramatic:
220          Originally:                          290
221          After changing UCP table:            187
222          After changing error message table:   43
223          After changing table of "verbs"       36
224          After changing table of Posix names   22
226        Thanks to the folks working on Gregex for glib for this insight.
228    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
229        unicode-properties was also set.
231    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
233    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
234        checked only for CRLF.
236    14. Added casts to pcretest.c to avoid compiler warnings.
238    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
240    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
241        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
242        entirely. This removes changes made in 7 above.
244    17. The CMake files have been updated, and there is now more information about
245        building with CMake in the NON-UNIX-USE document.
248    Version 7.3 28-Aug-07
249    ---------------------
251     1. In the rejigging of the build system that eventually resulted in 7.1, the
252        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
253        brackets there is not right, since it causes compilers to look for an
254        installed pcre.h, not the version that is in the source that is being
255        compiled (which of course may be different). I have changed it back to:
257          #include "pcre.h"
259        I have a vague recollection that the change was concerned with compiling in
260        different directories, but in the new build system, that is taken care of
261        by the VPATH setting the Makefile.
263     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
264        when the subject happened to end in the byte 0x85 (e.g. if the last
265        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
266        characters but of course it shouldn't be taken as a newline when it is part
267        of another character. The bug was that, for an unlimited repeat of . in
268        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
269        characters when looking for a newline.
271     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
273     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
274        in debug output.
276     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
277        long printing in the pcrecpp unittest when running under MinGW.
279     6. ESC_K was left out of the EBCDIC table.
281     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
282        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
283        limit also applies to "virtual nesting" when a pattern is recursive, and in
284        this case 1000 isn't so big. I have been able to remove this limit at the
285        expense of backing off one optimization in certain circumstances. Normally,
286        when pcre_exec() would call its internal match() function recursively and
287        immediately return the result unconditionally, it uses a "tail recursion"
288        feature to save stack. However, when a subpattern that can match an empty
289        string has an unlimited repetition quantifier, it no longer makes this
290        optimization. That gives it a stack frame in which to save the data for
291        checking that an empty string has been matched. Previously this was taken
292        from the 1000-entry workspace that had been reserved. So now there is no
293        explicit limit, but more stack is used.
295     8. Applied Daniel's patches to solve problems with the import/export magic
296        syntax that is required for Windows, and which was going wrong for the
297        pcreposix and pcrecpp parts of the library. These were overlooked when this
298        problem was solved for the main library.
300     9. There were some crude static tests to avoid integer overflow when computing
301        the size of patterns that contain repeated groups with explicit upper
302        limits. As the maximum quantifier is 65535, the maximum group length was
303        set at 30,000 so that the product of these two numbers did not overflow a
304        32-bit integer. However, it turns out that people want to use groups that
305        are longer than 30,000 bytes (though not repeat them that many times).
306        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
307        made it possible to implement the integer overflow checks in a much more
308        dynamic way, which I have now done. The artificial limitation on group
309        length has been removed - we now have only the limit on the total length of
310        the compiled pattern, which depends on the LINK_SIZE setting.
312    10. Fixed a bug in the documentation for get/copy named substring when
313        duplicate names are permitted. If none of the named substrings are set, the
314        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
315        empty string.
317    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
318        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
319        because the ] is interpreted as the first data character and the
320        terminating ] is not found. PCRE has been made compatible with Perl in this
321        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
322        cause memory overwriting.
324    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
325        string has been matched (to stop an infinite loop). It was not recognizing
326        a conditional subpattern that could match an empty string if that
327        subpattern was within another subpattern. For example, it looped when
328        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
329        condition was not nested. This bug has been fixed.
331    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
332        past the start of the subject in the presence of bytes with the top bit
333        set, for example "\x8aBCD".
335    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
336        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
338    14. Optimized (?!) to (*FAIL).
340    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
341        This restricts code points to be within the range 0 to 0x10FFFF, excluding
342        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
343        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
344        does: it's just the validity check that is more restrictive.
346    16. Inserted checks for integer overflows during escape sequence (backslash)
347        processing, and also fixed erroneous offset values for syntax errors during
348        backslash processing.
350    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
351        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
353    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
354        caused an overrun.
356    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
357        something other than just ASCII characters) inside a group that had an
358        unlimited repeat caused a loop at compile time (while checking to see
359        whether the group could match an empty string).
361    20. Debugging a pattern containing \p or \P could cause a crash. For example,
362        [\P{Any}] did so. (Error in the code for printing property names.)
364    21. An orphan \E inside a character class could cause a crash.
366    22. A repeated capturing bracket such as (A)? could cause a wild memory
367        reference during compilation.
369    23. There are several functions in pcre_compile() that scan along a compiled
370        expression for various reasons (e.g. to see if it's fixed length for look
371        behind). There were bugs in these functions when a repeated \p or \P was
372        present in the pattern. These operators have additional parameters compared
373        with \d, etc, and these were not being taken into account when moving along
374        the compiled data. Specifically:
376        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
377            length.
379        (b) An item such as \pL+ within a repeated group could cause crashes or
380            loops.
382        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
383            "reference to non-existent subpattern" error.
385        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
387    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
388        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
390    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
392    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
393        character were causing crashes (broken optimization).
395    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
396        \p or \P) caused a compile-time loop.
398    28. More problems have arisen in unanchored patterns when CRLF is a valid line
399        break. For example, the unstudied pattern [\r\n]A does not match the string
400        "\r\nA" because change 7.0/46 below moves the current point on by two
401        characters after failing to match at the start. However, the pattern \nA
402        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
403        the same is true. There doesn't seem any very clean way out of this, but
404        what I have chosen to do makes the common cases work: PCRE now takes note
405        of whether there can be an explicit match for \r or \n anywhere in the
406        pattern, and if so, 7.0/46 no longer applies. As part of this change,
407        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
408        pattern has explicit CR or LF references.
410    29. Added (*CR) etc for changing newline setting at start of pattern.
413    Version 7.2 19-Jun-07
414    ---------------------
416     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
417        which is apparently normally available under Windows.
419     2. Re-jig the pcregrep tests with different newline settings in an attempt
420        to make them independent of the local environment's newline setting.
422     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
424     4. Some of the "internals" tests were previously cut out when the link size
425        was not 2, because the output contained actual offsets. The recent new
426        "Z" feature of pcretest means that these can be cut out, making the tests
427        usable with all link sizes.
429     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
430        stack recursion. This gives a massive performance boost under BSD, but just
431        a small improvement under Linux. However, it saves one field in the frame
432        in all cases.
434     6. Added more features from the forthcoming Perl 5.10:
436        (a) (?-n) (where n is a string of digits) is a relative subroutine or
437            recursion call. It refers to the nth most recently opened parentheses.
439        (b) (?+n) is also a relative subroutine call; it refers to the nth next
440            to be opened parentheses.
442        (c) Conditions that refer to capturing parentheses can be specified
443            relatively, for example, (?(-2)... or (?(+3)...
445        (d) \K resets the start of the current match so that everything before
446            is not part of it.
448        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
450        (f) \g{name} is another synonym - part of Perl 5.10's unification of
451            reference syntax.
453        (g) (?| introduces a group in which the numbering of parentheses in each
454            alternative starts with the same number.
456        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
458     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
461     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
462        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
463        for detecting groups that can match an empty string.
465     9. A pattern with a very large number of alternatives (more than several
466        hundred) was running out of internal workspace during the pre-compile
467        phase, where pcre_compile() figures out how much memory will be needed. A
468        bit of new cunning has reduced the workspace needed for groups with
469        alternatives. The 1000-alternative test pattern now uses 12 bytes of
470        workspace instead of running out of the 4096 that are available.
472    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
474    11. Applied patch from Google to remove an optimization that didn't quite work.
475        The report of the bug said:
477          pcrecpp::RE("a*").FullMatch("aaa") matches, while
478          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
479          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
481    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
482        it matched the wrong number of bytes.
485    Version 7.1 24-Apr-07
486    ---------------------
488     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
489        that is more "standard", making use of automake and other Autotools. There
490        is some re-arrangement of the files and adjustment of comments consequent
491        on this.
493     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
494        for recursive directory scanning broke on some systems because the files
495        are not scanned in any specific order and on different systems the order
496        was different. A call to "sort" has been inserted into RunGrepTest for the
497        approprate test as a short-term fix. In the longer term there may be an
498        alternative.
500     3. I had an email from Eric Raymond about problems translating some of PCRE's
501        man pages to HTML (despite the fact that I distribute HTML pages, some
502        people do their own conversions for various reasons). The problems
503        concerned the use of low-level troff macros .br and .in. I have therefore
504        removed all such uses from the man pages (some were redundant, some could
505        be replaced by .nf/.fi pairs). The 132html script that I use to generate
506        HTML has been updated to handle .nf/.fi and to complain if it encounters
507        .br or .in.
509     4. Updated comments in configure.ac that get placed in config.h.in and also
510        arranged for config.h to be included in the distribution, with the name
511        config.h.generic, for the benefit of those who have to compile without
512        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
514     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
515        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
516        makevp.bat for the current PCRE, using the additional files
517        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
519     6. A Windows user reported a minor discrepancy with test 2, which turned out
520        to be caused by a trailing space on an input line that had got lost in his
521        copy. The trailing space was an accident, so I've just removed it.
523     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
524        that is needed.
526     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
527        as "const" (a) because they are and (b) because it helps the PHP
528        maintainers who have recently made a script to detect big data structures
529        in the php code that should be moved to the .rodata section. I remembered
530        to update Builducptable as well, so it won't revert if ucptable.h is ever
531        re-created.
533     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
534        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
535        order to be able to cut out the UTF-8 tables in the latter when UTF-8
536        support is not required. This saves 1.5-2K of code, which is important in
537        some applications.
539        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
540        so as not to refer to the tables, even though these functions will never be
541        called when UTF-8 support is disabled. Otherwise there are problems with a
542        shared library.
544    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
546        (a) It was defining its arguments as char * instead of void *.
548        (b) It was assuming that all moves were upwards in memory; this was true
549            a long time ago when I wrote it, but is no longer the case.
551        The emulated memove() is provided for those environments that have neither
552        memmove() nor bcopy(). I didn't think anyone used it these days, but that
553        is clearly not the case, as these two bugs were recently reported.
555    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
556        and Detrail to create the HTML documentation, the .txt form of the man
557        pages, and it removes trailing spaces from listed files. It also creates
558        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
559        case, it wraps all the #defines with #ifndefs. This script should be run
560        before "make dist".
562    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
563        with Unicode property support.
565        (a) For a maximizing quantifier, if the two different cases of the
566            character were of different lengths in their UTF-8 codings (there are
567            some cases like this - I found 11), and the matching function had to
568            back up over a mixture of the two cases, it incorrectly assumed they
569            were both the same length.
571        (b) When PCRE was configured to use the heap rather than the stack for
572            recursion during matching, it was not correctly preserving the data for
573            the other case of a UTF-8 character when checking ahead for a match
574            while processing a minimizing repeat. If the check also involved
575            matching a wide character, but failed, corruption could cause an
576            erroneous result when trying to check for a repeat of the original
577            character.
579    13. Some tidying changes to the testing mechanism:
581        (a) The RunTest script now detects the internal link size and whether there
582            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
583            values substituted by "configure". (The RunGrepTest script already did
584            this for UTF-8.) The configure.ac script no longer substitutes the
585            relevant variables.
587        (b) The debugging options /B and /D in pcretest show the compiled bytecode
588            with length and offset values. This means that the output is different
589            for different internal link sizes. Test 2 is skipped for link sizes
590            other than 2 because of this, bypassing the problem. Unfortunately,
591            there was also a test in test 3 (the locale tests) that used /B and
592            failed for link sizes other than 2. Rather than cut the whole test out,
593            I have added a new /Z option to pcretest that replaces the length and
594            offset values with spaces. This is now used to make test 3 independent
595            of link size. (Test 2 will be tidied up later.)
597    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
598        segmentation fault instead of returning the appropriate error message.
600    15. In multiline mode when the newline sequence was set to "any", the pattern
601        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
602        This doesn't seem right; it now treats the CRLF combination as the line
603        ending, and so does not match in that case. It's only a pattern such as ^$
604        that would hit this one: something like ^ABC$ would have failed after \r
605        and then tried again after \r\n.
607    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
608        in an attempt to make files that differ only in their line terminators
609        compare equal. This works on Linux.
611    17. Under certain error circumstances pcregrep might try to free random memory
612        as it exited. This is now fixed, thanks to valgrind.
614    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
615        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
616        was because its rules for how to advance for /g after matching an empty
617        string at the end of a line did not allow for this case. They now check for
618        it specially.
620    20. pcretest is supposed to handle patterns and data of any length, by
621        extending its buffers when necessary. It was getting this wrong when the
622        buffer for a data line had to be extended.
624    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
625        CRLF as a newline sequence.
627    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
628        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
629        I have nevertheless tidied it up.
631    23. Added some casts to kill warnings from HP-UX ia64 compiler.
633    24. Added a man page for pcre-config.
636    Version 7.0 19-Dec-06
637    ---------------------
639     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
640        moving to gcc 4.1.1.
642     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
643        sys/time.h, which is documented as needed for this function. It doesn't
644        seem to matter on Linux, but it showed up on some releases of OS X.
646     3. It seems that there are systems where bytes whose values are greater than
647        127 match isprint() in the "C" locale. The "C" locale should be the
648        default when a C program starts up. In most systems, only ASCII printing
649        characters match isprint(). This difference caused the output from pcretest
650        to vary, making some of the tests fail. I have changed pcretest so that:
652        (a) When it is outputting text in the compiled version of a pattern, bytes
653            other than 32-126 are always shown as hex escapes.
655        (b) When it is outputting text that is a matched part of a subject string,
656            it does the same, unless a different locale has been set for the match
657            (using the /L modifier). In this case, it uses isprint() to decide.
659     4. Fixed a major bug that caused incorrect computation of the amount of memory
660        required for a compiled pattern when options that changed within the
661        pattern affected the logic of the preliminary scan that determines the
662        length. The relevant options are -x, and -i in UTF-8 mode. The result was
663        that the computed length was too small. The symptoms of this bug were
664        either the PCRE error "internal error: code overflow" from pcre_compile(),
665        or a glibc crash with a message such as "pcretest: free(): invalid next
666        size (fast)". Examples of patterns that provoked this bug (shown in
667        pcretest format) are:
669          /(?-x: )/x
670          /(?x)(?-x: \s*#\s*)/
671          /((?i)[\x{c0}])/8
672          /(?i:[\x{c0}])/8
674        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
675        is now done differently.
677     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
678        wrapper classes; (b) implement a new function in the C++ scanner that is
679        more efficient than the old way of doing things because it avoids levels of
680        recursion in the regex matching; (c) add a paragraph to the documentation
681        for the FullMatch() function.
683     6. The escape sequence \n was being treated as whatever was defined as
684        "newline". Not only was this contrary to the documentation, which states
685        that \n is character 10 (hex 0A), but it also went horribly wrong when
686        "newline" was defined as CRLF. This has been fixed.
688     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
689        was being set to -1 for the "end of line" case (supposedly a value that no
690        character can have). Though this value is never used (the check for end of
691        line is "zero bytes in current character"), it caused compiler complaints.
692        I've changed it to 0xffffffff.
694     8. In pcre_version.c, the version string was being built by a sequence of
695        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
696        string (as it is for production releases) called a macro with an empty
697        argument. The C standard says the result of this is undefined. The gcc
698        compiler treats it as an empty string (which was what was wanted) but it is
699        reported that Visual C gives an error. The source has been hacked around to
700        avoid this problem.
702     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
703        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
704        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
705        of them did).
707    10. Originally, pcretest opened its input and output without "b"; then I was
708        told that "b" was needed in some environments, so it was added for release
709        5.0 to both the input and output. (It makes no difference on Unix-like
710        systems.) Later I was told that it is wrong for the input on Windows. I've
711        now abstracted the modes into two macros, to make it easier to fiddle with
712        them, and removed "b" from the input mode under Windows.
714    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
716    12. Added -help and --help to pcretest as an official way of being reminded
717        of the options.
719    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
720        and pcrecpp.cc because they annoy compilers at high warning levels.
722    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
724    15. Fixed an occurrence of == in configure.ac that should have been = (shell
725        scripts are not C programs :-) and which was not noticed because it works
726        on Linux.
728    16. pcretest is supposed to handle any length of pattern and data line (as one
729        line or as a continued sequence of lines) by extending its input buffer if
730        necessary. This feature was broken for very long pattern lines, leading to
731        a string of junk being passed to pcre_compile() if the pattern was longer
732        than about 50K.
734    17. I have done a major re-factoring of the way pcre_compile() computes the
735        amount of memory needed for a compiled pattern. Previously, there was code
736        that made a preliminary scan of the pattern in order to do this. That was
737        OK when PCRE was new, but as the facilities have expanded, it has become
738        harder and harder to keep it in step with the real compile phase, and there
739        have been a number of bugs (see for example, 4 above). I have now found a
740        cunning way of running the real compile function in a "fake" mode that
741        enables it to compute how much memory it would need, while actually only
742        ever using a few hundred bytes of working memory and without too many
743        tests of the mode. This should make future maintenance and development
744        easier. A side effect of this work is that the limit of 200 on the nesting
745        depth of parentheses has been removed (though this was never a serious
746        limitation, I suspect). However, there is a downside: pcre_compile() now
747        runs more slowly than before (30% or more, depending on the pattern). I
748        hope this isn't a big issue. There is no effect on runtime performance.
750    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
751        newline (only possible for the last line of a file) and it was a
752        pattern that set a locale (followed by /Lsomething), pcretest crashed.
754    19. Added additional timing features to pcretest. (1) The -tm option now times
755        matching only, not compiling. (2) Both -t and -tm can be followed, as a
756        separate command line item, by a number that specifies the number of
757        repeats to use when timing. The default is 50000; this gives better
758        precision, but takes uncomfortably long for very large patterns.
760    20. Extended pcre_study() to be more clever in cases where a branch of a
761        subpattern has no definite first character. For example, (a*|b*)[cd] would
762        previously give no result from pcre_study(). Now it recognizes that the
763        first character must be a, b, c, or d.
765    21. There was an incorrect error "recursive call could loop indefinitely" if
766        a subpattern (or the entire pattern) that was being tested for matching an
767        empty string contained only one non-empty item after a nested subpattern.
768        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
769        incorrectly, because the \d was being skipped in the check.
771    22. The pcretest program now has a new pattern option /B and a command line
772        option -b, which is equivalent to adding /B to every pattern. This causes
773        it to show the compiled bytecode, without the additional information that
774        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
775        is the same as /B/I).
777    23. A new optimization is now able automatically to treat some sequences such
778        as a*b as a*+b. More specifically, if something simple (such as a character
779        or a simple class like \d) has an unlimited quantifier, and is followed by
780        something that cannot possibly match the quantified thing, the quantifier
781        is automatically "possessified".
783    24. A recursive reference to a subpattern whose number was greater than 39
784        went wrong under certain circumstances in UTF-8 mode. This bug could also
785        have affected the operation of pcre_study().
787    25. Realized that a little bit of performance could be had by replacing
788        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
790    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
792    27. Possessive quantifiers such as a++ were previously implemented by turning
793        them into atomic groups such as ($>a+). Now they have their own opcodes,
794        which improves performance. This includes the automatically created ones
795        from 23 above.
797    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
798        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
799        the first matched character to be a colon. This applied both to named and
800        numbered groups.
802    29. The ucpinternal.h header file was missing its idempotency #ifdef.
804    30. I was sent a "project" file called libpcre.a.dev which I understand makes
805        building PCRE on Windows easier, so I have included it in the distribution.
807    31. There is now a check in pcretest against a ridiculously large number being
808        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
809        loop, the loop is abandoned.
811    32. Forward references to subpatterns in conditions such as (?(2)...) where
812        subpattern 2 is defined later cause pcre_compile() to search forwards in
813        the pattern for the relevant set of parentheses. This search went wrong
814        when there were unescaped parentheses in a character class, parentheses
815        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
817    33. "Subroutine" calls and backreferences were previously restricted to
818        referencing subpatterns earlier in the regex. This restriction has now
819        been removed.
821    34. Added a number of extra features that are going to be in Perl 5.10. On the
822        whole, these are just syntactic alternatives for features that PCRE had
823        previously implemented using the Python syntax or my own invention. The
824        other formats are all retained for compatibility.
826        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
827            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
828            also .NET compatible.
830        (b) A recursion or subroutine call to a named group can now be defined as
831            (?&name) as well as (?P>name).
833        (c) A backreference to a named group can now be defined as \k<name> or
834            \k'name' as well as (?P=name). The new forms, as well as being in Perl
835            5.10, are also .NET compatible.
837        (d) A conditional reference to a named group can now use the syntax
838            (?(<name>) or (?('name') as well as (?(name).
840        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
841            groups (named and numbered) that are never evaluated inline, but can be
842            called as "subroutines" from elsewhere. In effect, the DEFINE condition
843            is always false. There may be only one alternative in such a group.
845        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
846            as the simple (?(R). The condition is true only if the most recent
847            recursion is that of the given number or name. It does not search out
848            through the entire recursion stack.
850        (g) The escape \gN or \g{N} has been added, where N is a positive or
851            negative number, specifying an absolute or relative reference.
853    35. Tidied to get rid of some further signed/unsigned compiler warnings and
854        some "unreachable code" warnings.
856    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
857        things, this adds five new scripts.
859    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
860        There were also incompatibilities regarding the handling of \Q..\E inside
861        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
862        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
864    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
865        matches an empty string, and forcibly breaks the loop. There were bugs in
866        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
867        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
868        separate and independent bugs (that affected different cases) have been
869        fixed.
871    39. Refactored the code to abolish the use of different opcodes for small
872        capturing bracket numbers. This is a tidy that I avoided doing when I
873        removed the limit on the number of capturing brackets for 3.5 back in 2001.
874        The new approach is not only tidier, it makes it possible to reduce the
875        memory needed to fix the previous bug (38).
877    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
878        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
879        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
880        mode.
882    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
883        report.
885    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
886        copy construction and assignment in the C++ wrapper.
888    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
889        couple of bugs that could have given wrong results in the "--newline=crlf"
890        case.
892    44. Added a number of casts and did some reorganization of signed/unsigned int
893        variables following suggestions from Dair Grant. Also renamed the variable
894        "this" as "item" because it is a C++ keyword.
896    45. Arranged for dftables to add
898          #include "pcre_internal.h"
900        to pcre_chartables.c because without it, gcc 4.x may remove the array
901        definition from the final binary if PCRE is built into a static library and
902        dead code stripping is activated.
904    46. For an unanchored pattern, if a match attempt fails at the start of a
905        newline sequence, and the newline setting is CRLF or ANY, and the next two
906        characters are CRLF, advance by two characters instead of one.
909    Version 6.7 04-Jul-06
910    ---------------------
912     1. In order to handle tests when input lines are enormously long, pcretest has
913        been re-factored so that it automatically extends its buffers when
914        necessary. The code is crude, but this _is_ just a test program. The
915        default size has been increased from 32K to 50K.
917     2. The code in pcre_study() was using the value of the re argument before
918        testing it for NULL. (Of course, in any sensible call of the function, it
919        won't be NULL.)
921     3. The memmove() emulation function in pcre_internal.h, which is used on
922        systems that lack both memmove() and bcopy() - that is, hardly ever -
923        was missing a "static" storage class specifier.
925     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
926        containing an extended class (one that cannot be represented by a bitmap
927        because it contains high-valued characters or Unicode property items, e.g.
928        [\pZ]). Almost always one would set UTF-8 mode when processing such a
929        pattern, but PCRE should not loop if you do not (it no longer does).
930        [Detail: two cases were found: (a) a repeated subpattern containing an
931        extended class; (b) a recursive reference to a subpattern that followed a
932        previous extended class. It wasn't skipping over the extended class
933        correctly when UTF-8 mode was not set.]
935     5. A negated single-character class was not being recognized as fixed-length
936        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
937        compile error "lookbehind assertion is not fixed length".
939     6. The RunPerlTest auxiliary script was showing an unexpected difference
940        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
941        write a Perl script that can interpret lines of an input file either as
942        byte characters or as UTF-8, which is what "perltest" was being required to
943        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
944        can't do is switch easily at run time between having the "use utf8;" pragma
945        or not. In the end, I fudged it by using the RunPerlTest script to insert
946        "use utf8;" explicitly for the UTF-8 tests.
948     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
949        the end of the subject string, contrary to the documentation and to what
950        Perl does. This was true of both matching functions. Now it matches only at
951        the start of the subject and immediately after *internal* newlines.
953     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
954        a pointer to an int instead of a pointer to an unsigned long int. This
955        caused problems on 64-bit systems.
957     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
958        instance of the 'standard' template library not being so standard".
960    10. There was no check on the number of named subpatterns nor the maximum
961        length of a subpattern name. The product of these values is used to compute
962        the size of the memory block for a compiled pattern. By supplying a very
963        long subpattern name and a large number of named subpatterns, the size
964        computation could be caused to overflow. This is now prevented by limiting
965        the length of names to 32 characters, and the number of named subpatterns
966        to 10,000.
968    11. Subpatterns that are repeated with specific counts have to be replicated in
969        the compiled pattern. The size of memory for this was computed from the
970        length of the subpattern and the repeat count. The latter is limited to
971        65535, but there was no limit on the former, meaning that integer overflow
972        could in principle occur. The compiled length of a repeated subpattern is
973        now limited to 30,000 bytes in order to prevent this.
975    12. Added the optional facility to have named substrings with the same name.
977    13. Added the ability to use a named substring as a condition, using the
978        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
979        are numbers (not recommended). Forward references are permitted.
981    14. Added forward references in named backreferences (if you see what I mean).
983    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
984        pattern could run off the end of the subject. For example, the pattern
985        "(?s)(.{1,5})"8 did this with the subject "ab".
987    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
988        PCRE_CASELESS was set when matching characters that were quantified with ?
989        or *.
991    17. A character class other than a single negated character that had a minimum
992        but no maximum quantifier - for example [ab]{6,} - was not handled
993        correctly by pce_dfa_exec(). It would match only one character.
995    18. A valid (though odd) pattern that looked like a POSIX character
996        class but used an invalid character after [ (for example [[,abc,]]) caused
997        pcre_compile() to give the error "Failed: internal error: code overflow" or
998        in some cases to crash with a glibc free() error. This could even happen if
999        the pattern terminated after [[ but there just happened to be a sequence of
1000        letters, a binary zero, and a closing ] in the memory that followed.
1002    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1003        over the years. Originally (before any Unicode support), just the bottom 8
1004        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1005        output from "man perlunicode" includes this:
1007          The regular expression compiler produces polymorphic opcodes.  That
1008          is, the pattern adapts to the data and automatically switches to
1009          the Unicode character scheme when presented with Unicode data--or
1010          instead uses a traditional byte scheme when presented with byte
1011          data.
1013        Sadly, a wide octal escape does not cause a switch, and in a string with
1014        no other multibyte characters, these octal escapes are treated as before.
1015        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1016        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1017        Unicode string.
1019        I have not perpetrated such confusion in PCRE. Up till now, it took just
1020        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1021        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1022        translate to the appropriate multibyte character.
1024    29. Applied some refactoring to reduce the number of warnings from Microsoft
1025        and Borland compilers. This has included removing the fudge introduced
1026        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1027        a warning about an unused variable.
1029    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1030        characters since release 4.0, because Perl (from release 5.004) does not.
1031        [Or at least, is documented not to: some releases seem to be in conflict
1032        with the documentation.] However, when a pattern was studied with
1033        pcre_study() and all its branches started with \s, PCRE still included VT
1034        as a possible starting character. Of course, this did no harm; it just
1035        caused an unnecessary match attempt.
1037    22. Removed a now-redundant internal flag bit that recorded the fact that case
1038        dependency changed within the pattern. This was once needed for "required
1039        byte" processing, but is no longer used. This recovers a now-scarce options
1040        bit. Also moved the least significant internal flag bit to the most-
1041        significant bit of the word, which was not previously used (hangover from
1042        the days when it was an int rather than a uint) to free up another bit for
1043        the future.
1045    23. Added support for CRLF line endings as well as CR and LF. As well as the
1046        default being selectable at build time, it can now be changed at runtime
1047        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1048        specify that it is scanning data with non-default line endings.
1050    24. Changed the definition of CXXLINK to make it agree with the definition of
1051        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1053    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1054        recursions. This makes a big different to stack usage for some patterns.
1056    26. If a subpattern containing a named recursion or subroutine reference such
1057        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1058        the space required for the compiled pattern went wrong and gave too small a
1059        value. Depending on the environment, this could lead to "Failed: internal
1060        error: code overflow at offset 49" or "glibc detected double free or
1061        corruption" errors.
1063    27. Applied patches from Google (a) to support the new newline modes and (b) to
1064        advance over multibyte UTF-8 characters in GlobalReplace.
1066    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1067        difference for some implementation of PCRE in some Windows version.
1069    29. Added some extra testing facilities to pcretest:
1071        \q<number>   in a data line sets the "match limit" value
1072        \Q<number>   in a data line sets the "match recursion limt" value
1073        -S <number>  sets the stack size, where <number> is in megabytes
1075        The -S option isn't available for Windows.
1078    Version 6.6 06-Feb-06
1079    ---------------------
1081     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1082        in pcreposix.h. I have copied the definition from pcre.h.
1084     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1085        because pcre.h is no longer a built file.
1087     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1088        not normally included in the compiled code.
1091    Version 6.5 01-Feb-06
1092    ---------------------
1094     1. When using the partial match feature with pcre_dfa_exec(), it was not
1095        anchoring the second and subsequent partial matches at the new starting
1096        point. This could lead to incorrect results. For example, with the pattern
1097        /1234/, partially matching against "123" and then "a4" gave a match.
1099     2. Changes to pcregrep:
1101        (a) All non-match returns from pcre_exec() were being treated as failures
1102            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1103            error message is output. Some extra information is given for the
1104            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1105            probably the only errors that are likely to be caused by users (by
1106            specifying a regex that has nested indefinite repeats, for instance).
1107            If there are more than 20 of these errors, pcregrep is abandoned.
1109        (b) A binary zero was treated as data while matching, but terminated the
1110            output line if it was written out. This has been fixed: binary zeroes
1111            are now no different to any other data bytes.
1113        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1114            used to set a locale for matching. The --locale=xxxx long option has
1115            been added (no short equivalent) to specify a locale explicitly on the
1116            pcregrep command, overriding the environment variables.
1118        (d) When -B was used with -n, some line numbers in the output were one less
1119            than they should have been.
1121        (e) Added the -o (--only-matching) option.
1123        (f) If -A or -C was used with -c (count only), some lines of context were
1124            accidentally printed for the final match.
1126        (g) Added the -H (--with-filename) option.
1128        (h) The combination of options -rh failed to suppress file names for files
1129            that were found from directory arguments.
1131        (i) Added the -D (--devices) and -d (--directories) options.
1133        (j) Added the -F (--fixed-strings) option.
1135        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1137        (l) Added the --colo(u)r option.
1139        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1140            is not present by default.
1142     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1143        items such as (?R) or (?1), when the recursion could match a number of
1144        alternatives. If it matched one of the alternatives, but subsequently,
1145        outside the recursion, there was a failure, the code tried to back up into
1146        the recursion. However, because of the way PCRE is implemented, this is not
1147        possible, and the result was an incorrect result from the match.
1149        In order to prevent this happening, the specification of recursion has
1150        been changed so that all such subpatterns are automatically treated as
1151        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1153     4. I had overlooked the fact that, in some locales, there are characters for
1154        which isalpha() is true but neither isupper() nor islower() are true. In
1155        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1156        and ordfeminine) are like this. This affected the treatment of \w and \W
1157        when they appeared in character classes, but not when they appeared outside
1158        a character class. The bit map for "word" characters is now created
1159        separately from the results of isalnum() instead of just taking it from the
1160        upper, lower, and digit maps. (Plus the underscore character, of course.)
1162     5. The above bug also affected the handling of POSIX character classes such as
1163        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1164        permanent tables. Instead, the bit maps for such a class were previously
1165        created as the appropriate unions of the upper, lower, and digit bitmaps.
1166        Now they are created by subtraction from the [[:word:]] class, which has
1167        its own bitmap.
1169     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1170        It is created by subtracting the vertical space characters (\x09, \x0a,
1171        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1172        subtraction was done in the overall bitmap for a character class, meaning
1173        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1174        be recognized. This bug has been fixed.
1176     7. Patches from the folks at Google:
1178          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1179          real life, but is still worth protecting against".
1181          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1182          regular expressions".
1184          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1185          have it.
1187          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1188          "configure" and the latter not, in order to fix a problem somebody had
1189          with compiling the Arg class on HP-UX.
1191          (e) Improve the error-handling of the C++ wrapper a little bit.
1193          (f) New tests for checking recursion limiting.
1195     8. The pcre_memmove() function, which is used only if the environment does not
1196        have a standard memmove() function (and is therefore rarely compiled),
1197        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1198        returning a result (though PCRE never actually uses the result).
1200     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1201        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1202        returned instead of calling malloc() with an overflowing number that would
1203        most likely cause subsequent chaos.
1205    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1207    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1208        with this option is matched, the nmatch and pmatch options of regexec() are
1209        ignored.
1211    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1212        provided in case anyone wants to the the POSIX interface with UTF-8
1213        strings.
1215    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1216        C++ linking (needed for some HP-UX environments).
1218    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1219        (unused parameter) and in the pcre_printint() function (omitted "default"
1220        switch label when the default is to do nothing).
1222    15. Added some code to make it possible, when PCRE is compiled as a C++
1223        library, to replace subject pointers for pcre_exec() with a smart pointer
1224        class, thus making it possible to process discontinuous strings.
1226    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1227        much the same function. They were added by different people who were trying
1228        to make PCRE easy to compile on non-Unix systems. It has been suggested
1229        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1230        for compiling on Windows systems. I have therefore replaced it with
1231        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1232        defaults to "extern" for C or "extern C" for C++, which works fine on
1233        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1234        SCOPE with something explicit in config.h. In addition:
1236        (a) pcreposix.h still had just "extern" instead of either of these macros;
1237            I have replaced it with PCRE_DATA_SCOPE.
1239        (b) Functions such as _pcre_xclass(), which are internal to the library,
1240            but external in the C sense, all had PCRE_EXPORT in their definitions.
1241            This is apparently wrong for the Windows case, so I have removed it.
1242            (It makes no difference on Unix-like systems.)
1244    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1245        of recursive calls to match(). This is different to MATCH_LIMIT because
1246        that limits the total number of calls to match(), not all of which increase
1247        the depth of recursion. Limiting the recursion depth limits the amount of
1248        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1249        when PCRE is compiled, and changed at run time. A patch from Google adds
1250        this functionality to the C++ interface.
1252    18. Changes to the handling of Unicode character properties:
1254        (a) Updated the table to Unicode 4.1.0.
1256        (b) Recognize characters that are not in the table as "Cn" (undefined).
1258        (c) I revised the way the table is implemented to a much improved format
1259            which includes recognition of ranges. It now supports the ranges that
1260            are defined in UnicodeData.txt, and it also amalgamates other
1261            characters into ranges. This has reduced the number of entries in the
1262            table from around 16,000 to around 3,000, thus reducing its size
1263            considerably. I realized I did not need to use a tree structure after
1264            all - a binary chop search is just as efficient. Having reduced the
1265            number of entries, I extended their size from 6 bytes to 8 bytes to
1266            allow for more data.
1268        (d) Added support for Unicode script names via properties such as \p{Han}.
1270    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1271        matching that character.
1273    20. When matching a repeated Unicode property with a minimum greater than zero,
1274        (for example \pL{2,}), PCRE could look past the end of the subject if it
1275        reached it while seeking the minimum number of characters. This could
1276        happen only if some of the characters were more than one byte long, because
1277        there is a check for at least the minimum number of bytes.
1279    21. Refactored the implementation of \p and \P so as to be more general, to
1280        allow for more different types of property in future. This has changed the
1281        compiled form incompatibly. Anybody with saved compiled patterns that use
1282        \p or \P will have to recompile them.
1284    22. Added "Any" and "L&" to the supported property types.
1286    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1287        but give a compile time error if the value is greater than 0xff.
1289    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1290        accidentally not being installed or uninstalled.
1292    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1293        made were to insert the current release number. This seemed silly, because
1294        it made things harder for people building PCRE on systems that don't run
1295        "configure". I have turned pcre.h into a distributed file, no longer built
1296        by "configure", with the version identification directly included. There is
1297        no longer a pcre.h.in file.
1299        However, this change necessitated a change to the pcre-config script as
1300        well. It is built from pcre-config.in, and one of the substitutions was the
1301        release number. I have updated configure.ac so that ./configure now finds
1302        the release number by grepping pcre.h.
1304    26. Added the ability to run the tests under valgrind.
1307    Version 6.4 05-Sep-05
1308    ---------------------
1310     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1311        "--" to be printed when multiple files were scanned, even when none of the
1312        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1313        consider it to be a bug, and have restored the previous behaviour.
1315     2. A couple of code tidies to get rid of compiler warnings.
1317     3. The pcretest program used to cheat by referring to symbols in the library
1318        whose names begin with _pcre_. These are internal symbols that are not
1319        really supposed to be visible externally, and in some environments it is
1320        possible to suppress them. The cheating is now confined to including
1321        certain files from the library's source, which is a bit cleaner.
1323     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1324        file's purpose clearer.
1326     5. Reorganized pcre_ucp_findchar().
1329    Version 6.3 15-Aug-05
1330    ---------------------
1332     1. The file libpcre.pc.in did not have general read permission in the tarball.
1334     2. There were some problems when building without C++ support:
1336        (a) If C++ support was not built, "make install" and "make test" still
1337            tried to test it.
1339        (b) There were problems when the value of CXX was explicitly set. Some
1340            changes have been made to try to fix these, and ...
1342        (c) --disable-cpp can now be used to explicitly disable C++ support.
1344        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1345            backslash in a target when C++ was disabled. This confuses some
1346            versions of "make", apparently. Using an intermediate variable solves
1347            this. (Same for CPP_LOBJ.)
1349     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1350        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1351        necessary on certain architectures.
1353     4. Added a setting of -export-symbols-regex to the link command to remove
1354        those symbols that are exported in the C sense, but actually are local
1355        within the library, and not documented. Their names all begin with
1356        "_pcre_". This is not a perfect job, because (a) we have to except some
1357        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1358        available (and never for static libraries). I have made a note to try to
1359        find a way round (a) in the future.
1362    Version 6.2 01-Aug-05
1363    ---------------------
1365     1. There was no test for integer overflow of quantifier values. A construction
1366        such as {1111111111111111} would give undefined results. What is worse, if
1367        a minimum quantifier for a parenthesized subpattern overflowed and became
1368        negative, the calculation of the memory size went wrong. This could have
1369        led to memory overwriting.
1371     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1373     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1374        operating environments where this matters.
1376     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1377        PCRE options from within the C++ wrapper.
1379     5. Named capturing subpatterns were not being correctly counted when a pattern
1380        was compiled. This caused two problems: (a) If there were more than 100
1381        such subpatterns, the calculation of the memory needed for the whole
1382        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1383        back references of the form \12, where the number was greater than 9, were
1384        not recognized as back references, even though there were sufficient
1385        previous subpatterns.
1387     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1388        versions of gcc, e.g. 2.95.4.
1391    Version 6.1 21-Jun-05
1392    ---------------------
1394     1. There was one reference to the variable "posix" in pcretest.c that was not
1395        surrounded by "#if !defined NOPOSIX".
1397     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1398        the cross-check on the old pcre_info() function, for the benefit of the
1399        cut-down version of PCRE that is currently imported into Exim.
1401     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1402        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1403        patterns that start (?i) but I don't think that matters. The use of (?i) is
1404        just an example; this all applies to the other options as well.
1406     4. Since libtool seems to echo the compile commands it is issuing, the output
1407        from "make" can be reduced a bit by putting "@" in front of each libtool
1408        compile command.
1410     5. Patch from the folks at Google for configure.in to be a bit more thorough
1411        in checking for a suitable C++ installation before trying to compile the
1412        C++ stuff. This should fix a reported problem when a compiler was present,
1413        but no suitable headers.
1415     6. The man pages all had just "PCRE" as their title. I have changed them to
1416        be the relevant file name. I have also arranged that these names are
1417        retained in the file doc/pcre.txt, which is a concatenation in text format
1418        of all the man pages except the little individual ones for each function.
1420     7. The NON-UNIX-USE file had not been updated for the different set of source
1421        files that come with release 6. I also added a few comments about the C++
1422        wrapper.
1425    Version 6.0 07-Jun-05
1426    ---------------------
1428     1. Some minor internal re-organization to help with my DFA experiments.
1430     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1431        didn't matter for the library itself when fully configured, but did matter
1432        when compiling without UCP support, or within Exim, where the ucp files are
1433        not imported.
1435     3. Refactoring of the library code to split up the various functions into
1436        different source modules. The addition of the new DFA matching code (see
1437        below) to a single monolithic source would have made it really too
1438        unwieldy, quite apart from causing all the code to be include in a
1439        statically linked application, when only some functions are used. This is
1440        relevant even without the DFA addition now that patterns can be compiled in
1441        one application and matched in another.
1443        The downside of splitting up is that there have to be some external
1444        functions and data tables that are used internally in different modules of
1445        the library but which are not part of the API. These have all had their
1446        names changed to start with "_pcre_" so that they are unlikely to clash
1447        with other external names.
1449     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1450        a different (DFA) algorithm. Although it is slower than the original
1451        function, it does have some advantages for certain types of matching
1452        problem.
1454     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1455        including restarting after a partial match.
1457     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1458        defined when compiling for Windows was sent to me. I have put it into the
1459        code, though I have no means of testing or verifying it.
1461     7. Added the pcre_refcount() auxiliary function.
1463     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1464        match before or at the first newline in the subject string. In pcretest,
1465        the /f option on a pattern can be used to set this.
1467     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1468        would behave wrongly. This has been present in PCRE since release 4.0.
1470    10. A number of changes to the pcregrep command:
1472        (a) Refactored how -x works; insert ^(...)$ instead of setting
1473            PCRE_ANCHORED and checking the length, in preparation for adding
1474            something similar for -w.
1476        (b) Added the -w (match as a word) option.
1478        (c) Refactored the way lines are read and buffered so as to have more
1479            than one at a time available.
1481        (d) Implemented a pcregrep test script.
1483        (e) Added the -M (multiline match) option. This allows patterns to match
1484            over several lines of the subject. The buffering ensures that at least
1485            8K, or the rest of the document (whichever is the shorter) is available
1486            for matching (and similarly the previous 8K for lookbehind assertions).
1488        (f) Changed the --help output so that it now says
1490              -w, --word-regex(p)
1492            instead of two lines, one with "regex" and the other with "regexp"
1493            because that confused at least one person since the short forms are the
1494            same. (This required a bit of code, as the output is generated
1495            automatically from a table. It wasn't just a text change.)
1497        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1498            option but starts with a hyphen. Could be a pattern or a path name
1499            starting with a hyphen, for instance.
1501        (h) "-" can be given as a file name to represent stdin.
1503        (i) When file names are being printed, "(standard input)" is used for
1504            the standard input, for compatibility with GNU grep. Previously
1505            "<stdin>" was used.
1507        (j) The option --label=xxx can be used to supply a name to be used for
1508            stdin when file names are being printed. There is no short form.
1510        (k) Re-factored the options decoding logic because we are going to add
1511            two more options that take data. Such options can now be given in four
1512            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1514        (l) Added the -A, -B, and -C options for requesting that lines of context
1515            around matches be printed.
1517        (m) Added the -L option to print the names of files that do not contain
1518            any matching lines, that is, the complement of -l.
1520        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1521            continue to scan other files.
1523        (o) The -s option was incorrectly implemented. For compatibility with other
1524            greps, it now suppresses the error message for a non-existent or non-
1525            accessible file (but not the return code). There is a new option called
1526            -q that suppresses the output of matching lines, which was what -s was
1527            previously doing.
1529        (p) Added --include and --exclude options to specify files for inclusion
1530            and exclusion when recursing.
1532    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1533        Hopefully, it now does.
1535    12. Missing cast in pcre_study().
1537    13. Added an "uninstall" target to the makefile.
1539    14. Replaced "extern" in the function prototypes in Makefile.in with
1540        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1541        world, but is set differently for Windows.
1543    15. Added a second compiling function called pcre_compile2(). The only
1544        difference is that it has an extra argument, which is a pointer to an
1545        integer error code. When there is a compile-time failure, this is set
1546        non-zero, in addition to the error test pointer being set to point to an
1547        error message. The new argument may be NULL if no error number is required
1548        (but then you may as well call pcre_compile(), which is now just a
1549        wrapper). This facility is provided because some applications need a
1550        numeric error indication, but it has also enabled me to tidy up the way
1551        compile-time errors are handled in the POSIX wrapper.
1553    16. Added VPATH=.libs to the makefile; this should help when building with one
1554        prefix path and installing with another. (Or so I'm told by someone who
1555        knows more about this stuff than I do.)
1557    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1558        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1559        match everything, including newlines. This is not POSIX-compatible, but
1560        somebody wanted the feature. From pcretest it can be activated by using
1561        both the P and the s flags.
1563    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1565    19. libpcre.pc was being incorrectly installed as executable.
1567    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1568        it now also looks for '\r' so that it will work unmodified on Windows.
1570    21. Added Google's contributed C++ wrapper to the distribution.
1572    22. Added some untidy missing memory free() calls in pcretest, to keep
1573        Electric Fence happy when testing.
1577    Version 5.0 13-Sep-04
1578    ---------------------
1580     1. Internal change: literal characters are no longer packed up into items
1581        containing multiple characters in a single byte-string. Each character
1582        is now matched using a separate opcode. However, there may be more than one
1583        byte in the character in UTF-8 mode.
1585     2. The pcre_callout_block structure has two new fields: pattern_position and
1586        next_item_length. These contain the offset in the pattern to the next match
1587        item, and its length, respectively.
1589     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1590        insertion of callouts before each pattern item. Added the /C option to
1591        pcretest to make use of this.
1593     4. On the advice of a Windows user, the lines
1595          #if defined(_WIN32) || defined(WIN32)
1596          _setmode( _fileno( stdout ), 0x8000 );
1597          #endif  /* defined(_WIN32) || defined(WIN32) */
1599        have been added to the source of pcretest. This apparently does useful
1600        magic in relation to line terminators.
1602     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1603        for the benefit of those environments where the "b" makes a difference.
1605     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1606        to know about it. I have put a hack into configure.in that adds in code
1607        to set GCC=yes if CC=icc. This seems to end up at a point in the
1608        generated configure script that is early enough to affect the setting of
1609        compiler options, which is what is needed, but I have no means of testing
1610        whether it really works. (The user who reported this had patched the
1611        generated configure script, which of course I cannot do.)
1613        LATER: After change 22 below (new libtool files), the configure script
1614        seems to know about icc (and also ecc). Therefore, I have commented out
1615        this hack in configure.in.
1617     7. Added support for pkg-config (2 patches were sent in).
1619     8. Negated POSIX character classes that used a combination of internal tables
1620        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1621        [[:^ascii]]. Typically, they would match almost any characters. The other
1622        POSIX classes were not broken in this way.
1624     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1625        to find the match, as PCRE was deluded into thinking that the match had to
1626        start at the start point or following a newline. The same bug applied to
1627        patterns with negative forward assertions or any backward assertions
1628        preceding ".*" at the start, unless the pattern required a fixed first
1629        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1631    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1632        starting at the last subject character, bytes beyond the end of the subject
1633        string were read.
1635    11. Renamed the variable "class" as "classbits" to make life easier for C++
1636        users. (Previously there was a macro definition, but it apparently wasn't
1637        enough.)
1639    12. Added the new field "tables" to the extra data so that tables can be passed
1640        in at exec time, or the internal tables can be re-selected. This allows
1641        a compiled regex to be saved and re-used at a later time by a different
1642        program that might have everything at different addresses.
1644    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1645        -R library as well as a -L library.
1647    14. The debugging options of pcretest (-d on the command line or D on a
1648        pattern) showed incorrect output for anything following an extended class
1649        that contained multibyte characters and which was followed by a quantifier.
1651    15. Added optional support for general category Unicode character properties
1652        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1653        support. It adds about 90K to the size of the library. The meanings of the
1654        inbuilt class escapes such as \d and \s have NOT been changed.
1656    16. Updated pcredemo.c to include calls to free() to release the memory for the
1657        compiled pattern.
1659    17. The generated file chartables.c was being created in the source directory
1660        instead of in the building directory. This caused the build to fail if the
1661        source directory was different from the building directory, and was
1662        read-only.
1664    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1665        file. No doubt somebody will tell me if they don't make sense... Also added
1666        Dan Mooney's comments about building on OpenVMS.
1668    19. Added support for partial matching via the PCRE_PARTIAL option for
1669        pcre_exec() and the \P data escape in pcretest.
1671    20. Extended pcretest with 3 new pattern features:
1673        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1674              write the compiled pattern to the file whose name is "rest-of-line".
1675              This is a straight binary dump of the data, with the saved pointer to
1676              the character tables forced to be NULL. The study data, if any, is
1677              written too. After writing, pcretest reads a new pattern.
1679        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1680              compiled pattern from the given file. There must not be any
1681              occurrences of "<" in the file name (pretty unlikely); if there are,
1682              pcretest will instead treat the initial "<" as a pattern delimiter.
1683              After reading in the pattern, pcretest goes on to read data lines as
1684              usual.
1686        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1687              and 16-bit fields in a compiled pattern, to simulate a pattern that
1688              was compiled on a host of opposite endianness.
1690    21. The pcre-exec() function can now cope with patterns that were compiled on
1691        hosts of opposite endianness, with this restriction:
1693          As for any compiled expression that is saved and used later, the tables
1694          pointer field cannot be preserved; the extra_data field in the arguments
1695          to pcre_exec() should be used to pass in a tables address if a value
1696          other than the default internal tables were used at compile time.
1698    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1699        now diagnosed as an error. Previously, most of the time, a negative number
1700        would have been treated as zero, but if in addition "ovector" was passed as
1701        NULL, a crash could occur.
1703    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1704        new versions from the libtool 1.5 distribution (the last one is a copy of
1705        a file called libtool.m4). This seems to have fixed the need to patch
1706        "configure" to support Darwin 1.3 (which I used to do). However, I still
1707        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1708        workstation).
1710    24. Changed the PCRE licence to be the more standard "BSD" licence.
1713    Version 4.5 01-Dec-03
1714    ---------------------
1716     1. There has been some re-arrangement of the code for the match() function so
1717        that it can be compiled in a version that does not call itself recursively.
1718        Instead, it keeps those local variables that need separate instances for
1719        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1720        needs to "recurse". Keeping track of where control must go is done by means
1721        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1722        hide most of the details from the main code, and operates only if
1723        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1724        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1725        operating.
1727        To make it easier for callers to provide specially tailored get/free
1728        functions for this usage, two new functions, pcre_stack_malloc, and
1729        pcre_stack_free, are used. They are always called in strict stacking order,
1730        and the size of block requested is always the same.
1732        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1733        PCRE has been compiled to use the stack or the heap for recursion. The
1734        -C option of pcretest uses this to show which version is compiled.
1736        A new data escape \S, is added to pcretest; it causes the amounts of store
1737        obtained and freed by both kinds of malloc/free at match time to be added
1738        to the output.
1740     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1741        what's available on my current Linux desktop machine.
1743     3. When matching a UTF-8 string, the test for a valid string at the start has
1744        been extended. If start_offset is not zero, PCRE now checks that it points
1745        to a byte that is the start of a UTF-8 character. If not, it returns
1746        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1747        this is necessary because there may be backward assertions in the pattern.
1748        When matching the same subject several times, it may save resources to use
1749        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1751     4. The code for checking the validity of UTF-8 strings has been tightened so
1752        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1753        containing "overlong sequences".
1755     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1756        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1757        should have been "&", but it just so happened that all the cases this let
1758        through by mistake were picked up later in the function.
1760     6. I had used a variable called "isblank" - this is a C99 function, causing
1761        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1763     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1764        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1765        so the version is shown; (c) stop "make test" echoing "./RunTest".
1767     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1769     9. The prototype for memmove() for systems that don't have it was using
1770        size_t, but the inclusion of the header that defines size_t was later. I've
1771        moved the #includes for the C headers earlier to avoid this.
1773    10. Added some adjustments to the code to make it easier to compiler on certain
1774        special systems:
1776          (a) Some "const" qualifiers were missing.
1777          (b) Added the macro EXPORT before all exported functions; by default this
1778              is defined to be empty.
1779          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1780              that it reads its output file name as an argument instead of writing
1781              to the standard output and assuming this can be redirected.
1783    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1784        class containing characters with values greater than 255, PCRE compilation
1785        went into a loop.
1787    12. A recursive reference to a subpattern that was within another subpattern
1788        that had a minimum quantifier of zero caused PCRE to crash. For example,
1789        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1790        recursion. If the recursively-called subpattern itself had a zero repeat,
1791        that was OK.
1793    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1794        buffer into which it was copied (for escape processing) was still set at
1795        1024, so long lines caused crashes.
1797    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1798        "internal error: code overflow...". This applied to any character class
1799        that was followed by a possessive quantifier.
1801    15. Modified the Makefile to add libpcre.la as a prerequisite for
1802        libpcreposix.la because I was told this is needed for a parallel build to
1803        work.
1805    16. If a pattern that contained .* following optional items at the start was
1806        studied, the wrong optimizing data was generated, leading to matching
1807        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1808        matching string must start with a or b or c. The correct conclusion for
1809        this pattern is that a match can start with any character.
1812    Version 4.4 13-Aug-03
1813    ---------------------
1815     1. In UTF-8 mode, a character class containing characters with values between
1816        127 and 255 was not handled correctly if the compiled pattern was studied.
1817        In fixing this, I have also improved the studying algorithm for such
1818        classes (slightly).
1820     2. Three internal functions had redundant arguments passed to them. Removal
1821        might give a very teeny performance improvement.
1823     3. Documentation bug: the value of the capture_top field in a callout is *one
1824        more than* the number of the hightest numbered captured substring.
1826     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1827        in incorrectly linking with a previously installed version. They now link
1828        explicitly with libpcre.la.
1830     5. configure.in no longer needs to recognize Cygwin specially.
1832     6. A problem in pcre.in for Windows platforms is fixed.
1834     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1835        pcretest, it used to include the size of the study block as part of its
1836        output. Unfortunately, the structure contains a field that has a different
1837        size on different hardware architectures. This meant that the tests that
1838        showed this size failed. As the block is currently always of a fixed size,
1839        this information isn't actually particularly useful in pcretest output, so
1840        I have just removed it.
1842     8. Three pre-processor statements accidentally did not start in column 1.
1843        Sadly, there are *still* compilers around that complain, even though
1844        standard C has not required this for well over a decade. Sigh.
1846     9. In pcretest, the code for checking callouts passed small integers in the
1847        callout_data field, which is a void * field. However, some picky compilers
1848        complained about the casts involved for this on 64-bit systems. Now
1849        pcretest passes the address of the small integer instead, which should get
1850        rid of the warnings.
1852    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1853        both compile and run time, and gives an error if an invalid UTF-8 sequence
1854        is found. There is a option for disabling this check in cases where the
1855        string is known to be correct and/or the maximum performance is wanted.
1857    11. In response to a bug report, I changed one line in Makefile.in from
1859            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1860        to
1861            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1863        to look similar to other lines, but I have no way of telling whether this
1864        is the right thing to do, as I do not use Windows. No doubt I'll get told
1865        if it's wrong...
1868    Version 4.3 21-May-03
1869    ---------------------
1871    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1872       Makefile.
1874    2. Some refactoring to improve the quality of the code:
1876       (i)   The utf8_table... variables are now declared "const".
1878       (ii)  The code for \cx, which used the "case flipping" table to upper case
1879             lower case letters, now just substracts 32. This is ASCII-specific,
1880             but the whole concept of \cx is ASCII-specific, so it seems
1881             reasonable.
1883       (iii) PCRE was using its character types table to recognize decimal and
1884             hexadecimal digits in the pattern. This is silly, because it handles
1885             only 0-9, a-f, and A-F, but the character types table is locale-
1886             specific, which means strange things might happen. A private
1887             table is now used for this - though it costs 256 bytes, a table is
1888             much faster than multiple explicit tests. Of course, the standard
1889             character types table is still used for matching digits in subject
1890             strings against \d.
1892       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1893             ending in _t are). So I've renamed it as ESC_tee.
1895    3. The first argument for regexec() in the POSIX wrapper should have been
1896       defined as "const".
1898    4. Changed pcretest to use malloc() for its buffers so that they can be
1899       Electric Fenced for debugging.
1901    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1902       to read one or more bytes before the start of the subject string. Often this
1903       had no effect on PCRE's behaviour, but in some circumstances it could
1904       provoke a segmentation fault.
1906    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1907       to try to read one or more bytes before the start of the subject string.
1909    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1910       UTF-8 support could misbehave in various ways if the subject string
1911       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1912       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1913       back over UTF-8 characters.)
1916    Version 4.2 14-Apr-03
1917    ---------------------
1919    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1921    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1922         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1923         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1924         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1925         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1926           and BUILD_EXEEXT
1927         Note: automatic setting of the BUILD variables is not yet working
1928         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1929           compile-time but not at link-time
1930         [LINK]: use for linking executables only
1931         make different versions for Windows and non-Windows
1932         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1933           libraries
1934         [LINK_FOR_BUILD]: new variable
1935         [OBJEXT]: use throughout
1936         [EXEEXT]: use throughout
1937         <winshared>: new target
1938         <wininstall>: new target
1939         <dftables.o>: use native compiler
1940         <dftables>: use native linker
1941         <install>: handle Windows platform correctly
1942         <clean>: ditto
1943         <check>: ditto
1944         copy DLL to top builddir before testing
1946       As part of these changes, -no-undefined was removed again. This was reported
1947       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1948       in any case.
1950    3. Some tidies to get rid of compiler warnings:
1952       . In the match_data structure, match_limit was an unsigned long int, whereas
1953         match_call_count was an int. I've made them both unsigned long ints.
1955       . In pcretest the fact that a const uschar * doesn't automatically cast to
1956         a void * provoked a warning.
1958       . Turning on some more compiler warnings threw up some "shadow" variables
1959         and a few more missing casts.
1961    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1962       option, a class that contained a single character with a value between 128
1963       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1965    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1966       option, a class that contained several characters, but with at least one
1967       whose value was between 128 and 255 caused PCRE to crash.
1970    Version 4.1 12-Mar-03
1971    ---------------------
1973    1. Compiling with gcc -pedantic found a couple of places where casts were
1974    needed, and a string in dftables.c that was longer than standard compilers are
1975    required to support.
1977    2. Compiling with Sun's compiler found a few more places where the code could
1978    be tidied up in order to avoid warnings.
1980    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1981    first of these names is deprecated in the latest Autoconf in favour of the name
1982    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1983    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1984    analogy I have changed it to CFLAGS_FOR_BUILD.
1986    4. Added -no-undefined to the linking command in the Makefile, because this is
1987    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1988    linking step for the pcreposix library.
1990    5. PCRE was failing to diagnose the case of two named groups with the same
1991    name.
1993    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1994    literal character that is needed in the subject for a match, and scans along to
1995    ensure that it is present before embarking on the full matching process. This
1996    saves time in cases of nested unlimited repeats that are never going to match.
1997    Problem: the scan can take a lot of time if the subject is very long (e.g.
1998    megabytes), thus penalizing straightforward matches. It is now done only if the
1999    amount of subject to be scanned is less than 1000 bytes.
2001    7. A lesser problem with the same optimization is that it was recording the
2002    first character of an anchored pattern as "needed", thus provoking a search
2003    right along the subject, even when the first match of the pattern was going to
2004    fail. The "needed" character is now not set for anchored patterns, unless it
2005    follows something in the pattern that is of non-fixed length. Thus, it still
2006    fulfils its original purpose of finding quick non-matches in cases of nested
2007    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2010    Version 4.0 17-Feb-03
2011    ---------------------
2013    1. If a comment in an extended regex that started immediately after a meta-item
2014    extended to the end of string, PCRE compiled incorrect data. This could lead to
2015    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2017    2. Moved to autoconf 2.53 and libtool 1.4.2.
2019    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2020    the special perltest8 script is no longer needed - all the tests can be run
2021    from a single perltest script.
2023    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2024    by \s. It has now been removed in PCRE. This means it isn't recognized as
2025    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2026    class [:space:] *does* include VT, thereby creating a mess.
2028    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2029    space and tab.
2031    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2032    its new features into the main test script, reducing the number of scripts.
2034    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2035    were backward compatible, and made the (?i) apply to the whole pattern, as if
2036    /i were given. Now it behaves more logically, and applies the option setting
2037    only to what follows. PCRE has been changed to follow suit. However, if it
2038    finds options settings right at the start of the pattern, it extracts them into
2039    the global options, as before. Thus, they show up in the info data.
2041    8. Added support for the \Q...\E escape sequence. Characters in between are
2042    treated as literals. This is slightly different from Perl in that $ and @ are
2043    also handled as literals inside the quotes. In Perl, they will cause variable
2044    interpolation. Note the following examples:
2046        Pattern            PCRE matches      Perl matches
2048        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2049        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2050        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2052    For compatibility with Perl, \Q...\E sequences are recognized inside character
2053    classes as well as outside them.
2055    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2056    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2057    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2058    signed/unsigned warnings.
2060    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2061    option for pcretest, so I've replaced it by a simple function that does just
2062    that job.
2064    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2065    "pcregrep -".
2067    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2068    Java package. This provides some syntactic sugar for simple cases of what my
2069    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2070    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2071    item, you can use this simplified notation. Note that only makes sense with
2072    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2073    greediness, whatever the setting of the PCRE_UNGREEDY option.
2075    13. A change of greediness default within a pattern was not taking effect at
2076    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2077    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2078    was abstracted outside.
2080    14. PCRE now supports the \G assertion. It is true when the current matching
2081    position is at the start point of the match. This differs from \A when the
2082    starting offset is non-zero. Used with the /g option of pcretest (or similar
2083    code), it works in the same way as it does for Perl's /g option. If all
2084    alternatives of a regex begin with \G, the expression is anchored to the start
2085    match position, and the "anchored" flag is set in the compiled expression.
2087    15. Some bugs concerning the handling of certain option changes within patterns
2088    have been fixed. These applied to options other than (?ims). For example,
2089    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2090    been the other way round. Some of this was related to change 7 above.
2092    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2093    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2094    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2095    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2097    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2098    mode. Unlike ".", it always matches newline, whatever the setting of
2099    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2100    assertions. Perl allows it, but it doesn't (in general) work because it can't
2101    calculate the length of the lookbehind. At least, that's the case for Perl
2102    5.8.0 - I've been told they are going to document that it doesn't work in
2103    future.
2105    18. Added an error diagnosis for escapes that PCRE does not support: these are
2106    \L, \l, \N, \P, \p, \U, \u, and \X.
2108    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2109    reading past the end of the pattern in cases such as /[abcd/.
2111    20. PCRE was getting more memory than necessary for patterns with classes that
2112    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2114    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2115    compiling PCRE for use with Virtual Pascal.
2117    22. Small fix to the Makefile to make it work properly if the build is done
2118    outside the source tree.
2120    23. Added a new extension: a condition to go with recursion. If a conditional
2121    subpattern starts with (?(R) the "true" branch is used if recursion has
2122    happened, whereas the "false" branch is used only at the top level.
2124    24. When there was a very long string of literal characters (over 255 bytes
2125    without UTF support, over 250 bytes with UTF support), the computation of how
2126    much memory was required could be incorrect, leading to segfaults or other
2127    strange effects.
2129    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2130    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2131    there was a subsequent back reference to those brackets. This meant that, for
2132    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2133    possible to check for precisely this case. All we can do is abandon the
2134    optimization if .* occurs inside capturing brackets when there are any back
2135    references whatsoever. (See below for a better fix that came later.)
2137    26. The handling of the optimization for finding the first character of a
2138    non-anchored pattern, and for finding a character that is required later in the
2139    match were failing in some cases. This didn't break the matching; it just
2140    failed to optimize when it could. The way this is done has been re-implemented.
2142    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2144    28. Added a new feature that provides some of the functionality that Perl
2145    provides with (?{...}). The facility is termed a "callout". The way it is done
2146    in PCRE is for the caller to provide an optional function, by setting
2147    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2148    global variable. By default it is unset, which disables all calling out. To get
2149    the function called, the regex must include (?C) at appropriate points. This
2150    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2151    This provides a means of identifying different callout points. When PCRE
2152    reaches such a point in the regex, if pcre_callout has been set, the external
2153    function is called. It is provided with data in a structure called
2154    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2155    matching continues; if it returns a non-zero value, the match at the current
2156    point fails. However, backtracking will occur if possible. [This was changed
2157    later and other features added - see item 49 below.]
2159    29. pcretest is upgraded to test the callout functionality. It provides a
2160    callout function that displays information. By default, it shows the start of
2161    the match and the current position in the text. There are some new data escapes
2162    to vary what happens:
2164        \C+         in addition, show current contents of captured substrings
2165        \C-         do not supply a callout function
2166        \C!n        return 1 when callout number n is reached
2167        \C!n!m      return 1 when callout number n is reached for the mth time
2169    30. If pcregrep was called with the -l option and just a single file name, it
2170    output "<stdin>" if a match was found, instead of the file name.
2172    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2173    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2174    pcre_exec(). This saves a malloc/free per call. The default value of
2175    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2176    when configuring.
2178    32. The default maximum size of a compiled pattern is 64K. There have been a
2179    few cases of people hitting this limit. The code now uses macros to handle the
2180    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2181    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2182    configuring. Tests 2 and 5 work only with 2-byte links because they output
2183    debugging information about compiled patterns.
2185    33. Internal code re-arrangements:
2187    (a) Moved the debugging function for printing out a compiled regex into
2188        its own source file (printint.c) and used #include to pull it into
2189        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2190        separate copies.
2192    (b) Defined the list of op-code names for debugging as a macro in
2193        internal.h so that it is next to the definition of the opcodes.
2195    (c) Defined a table of op-code lengths for simpler skipping along compiled
2196        code. This is again a macro in internal.h so that it is next to the
2197        definition of the opcodes.
2199    34. Added support for recursive calls to individual subpatterns, along the
2200    lines of Robin Houston's patch (but implemented somewhat differently).
2202    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2203    allow it to read and process whole directories in Win32. This code was
2204    contributed by Lionel Fourquaux; it has not been tested by me.
2206    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2207    used to name a group. Names consist of alphanumerics and underscores, and must
2208    be unique. Back references use the syntax (?P=name) and recursive calls use
2209    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2210    numbers. The function pcre_fullinfo() can be used after compilation to extract
2211    a name/number map. There are three relevant calls:
2213      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2214      PCRE_INFO_NAMECOUNT            yields the number of entries
2215      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2217    The map is a vector of fixed-size entries. The size of each entry depends on
2218    the length of the longest name used. The first two bytes of each entry are the
2219    group number, most significant byte first. There follows the corresponding
2220    name, zero terminated. The names are in alphabetical order.
2222    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2223    case instead of 255. Making it the same both with and without UTF-8 support
2224    means that the same test output works with both.
2226    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2227    calling malloc() with a zero argument.
2229    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2230    optimization. I've improved things by keeping a bitmap of backreferences with
2231    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2232    fact referenced, the optimization can be applied. It is unlikely that a
2233    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2234    the match to follow \n) will appear inside brackets with a number greater than
2235    31, but if it does, any back reference > 31 suppresses the optimization.
2237    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2238    of disabling numbered capturing parentheses. Any opening parenthesis that is
2239    not followed by ? behaves as if it were followed by ?: but named parentheses
2240    can still be used for capturing (and they will acquire numbers in the usual
2241    way).
2243    41. Redesigned the return codes from the match() function into yes/no/error so
2244    that errors can be passed back from deep inside the nested calls. A malloc
2245    failure while inside a recursive subpattern call now causes the
2246    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2248    42. It is now possible to set a limit on the number of times the match()
2249    function is called in a call to pcre_exec(). This facility makes it possible to
2250    limit the amount of recursion and backtracking, though not in a directly
2251    obvious way, because the match() function is used in a number of different
2252    circumstances. The count starts from zero for each position in the subject
2253    string (for non-anchored patterns). The default limit is, for compatibility, a
2254    large number, namely 10 000 000. You can change this in two ways:
2256    (a) When configuring PCRE before making, you can use --with-match-limit=n
2257        to set a default value for the compiled library.
2259    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2260        a different value is set. See 45 below.
2262    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2264    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2265    of things that can be changed at compile time. The first argument specifies
2266    what is wanted and the second points to where the information is to be placed.
2267    The current list of available information is:
2269      PCRE_CONFIG_UTF8
2271    The output is an integer that is set to one if UTF-8 support is available;
2272    otherwise it is set to zero.
2276    The output is an integer that it set to the value of the code that is used for
2277    newline. It is either LF (10) or CR (13).
2281    The output is an integer that contains the number of bytes used for internal
2282    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2286    The output is an integer that contains the threshold above which the POSIX
2287    interface uses malloc() for output vectors. See item 31 above.
2291    The output is an unsigned integer that contains the default limit of the number
2292    of match() calls in a pcre_exec() execution. See 42 above.
2294    44. pcretest has been upgraded by the addition of the -C option. This causes it
2295    to extract all the available output from the new pcre_config() function, and to
2296    output it. The program then exits immediately.
2298    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2299    order to support additional features. One way would have been to define
2300    pcre_exec2() (for example) with extra arguments, but this would not have been
2301    extensible, and would also have required all calls to the original function to
2302    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2303    is used for passing in "extra" data from pcre_study().
2305    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2306    contains the following fields:
2308      flags         a bitmap indicating which of the following fields are set
2309      study_data    opaque data from pcre_study()
2310      match_limit   a way of specifying a limit on match() calls for a specific
2311                      call to pcre_exec()
2312      callout_data  data for callouts (see 49 below)
2314    The flag bits are also defined in pcre.h, and are
2320    The pcre_study() function now returns one of these new pcre_extra blocks, with
2321    the actual study data pointed to by the study_data field, and the
2322    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2323    before. That is, this change is entirely upwards-compatible and requires no
2324    change to existing code.
2326    If you want to pass in additional data to pcre_exec(), you can either place it
2327    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2328    block.
2330    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2331    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2332    times with different match limits, until it finds the minimum value needed for
2333    pcre_exec() to complete. The value is then output. This can be instructive; for
2334    most simple matches the number is quite small, but for pathological cases it
2335    gets very large very quickly.
2337    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2338    returns the size of the data block pointed to by the study_data field in a
2339    pcre_extra block, that is, the value that was passed as the argument to
2340    pcre_malloc() when PCRE was getting memory in which to place the information
2341    created by pcre_study(). The fourth argument should point to a size_t variable.
2342    pcretest has been extended so that this information is shown after a successful
2343    pcre_study() call when information about the compiled regex is being displayed.
2345    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2346    because what follows is always an absolute path. (Later: it turns out that this
2347    is more than cosmetic for MinGW, because it doesn't like empty path
2348    components.)
2350    49. Some changes have been made to the callout feature (see 28 above):
2352    (i)  A callout function now has three choices for what it returns:
2354           0  =>  success, carry on matching
2355         > 0  =>  failure at this point, but backtrack if possible
2356         < 0  =>  serious error, return this value from pcre_exec()
2358         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2359         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2360         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2361         use by callout functions. It will never be used by PCRE itself.
2363    (ii) The pcre_extra structure (see 45 above) has a void * field called
2364         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2365         pcre_callout_block structure has a field of the same name. The contents of
2366         the field passed in the pcre_extra structure are passed to the callout
2367         function in the corresponding field in the callout block. This makes it
2368         easier to use the same callout-containing regex from multiple threads. For
2369         testing, the pcretest program has a new data escape
2371           \C*n        pass the number n (may be negative) as callout_data
2373         If the callout function in pcretest receives a non-zero value as
2374         callout_data, it returns that value.
2376    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2377    there were some redundant $(CFLAGS) in commands that are now specified as
2378    $(LINK), which already includes $(CFLAGS).
2380    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2381    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2382    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2383    one-byte characters throughout. Note that case-insensitive matching applies
2384    only to characters whose values are less than 256. PCRE doesn't support the
2385    notion of cases for higher-valued characters.
2387    (i)   A character class whose characters are all within 0-255 is handled as
2388          a bit map, and the map is inverted for negative classes. Previously, a
2389          character > 255 always failed to match such a class; however it should
2390          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2392    (ii)  A negated character class with a single character < 255 is coded as
2393          "not this character" (OP_NOT). This wasn't working properly when the test
2394          character was multibyte, either singly or repeated.
2396    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2397          mode, for example: \x{100}{2,3}.
2399    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2400          singly or repeated) now correctly test multibyte characters. However,
2401          PCRE doesn't recognize any characters with values greater than 255 as
2402          digits, spaces, or word characters. Such characters always match \D, \S,
2403          and \W, and never match \d, \s, or \w.
2405    (v)   Classes may now contain characters and character ranges with values
2406          greater than 255. For example: [ab\x{100}-\x{400}].
2408    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2409          PCRE in UTF-8 mode.
2411    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2412    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2413    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2414    value.)
2416    53. The single man page has become too large. I have therefore split it up into
2417    a number of separate man pages. These also give rise to individual HTML pages;
2418    these are now put in a separate directory, and there is an index.html page that
2419    lists them all. Some hyperlinking between the pages has been installed.
2421    54. Added convenience functions for handling named capturing parentheses.
2423    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2424    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2425    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2426    are faulted.
2428    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2429    calling configure. These values are used when compiling the dftables.c program
2430    which is run to generate the source of the default character tables. They
2431    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2432    you will need to set these values.
2434    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2437    Version 3.9 02-Jan-02
2438    ---------------------
2440    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2442    2. If --disable-static was given, the building process failed when trying to
2443    build pcretest and pcregrep. (For some reason it was using libtool to compile
2444    them, which is not right, as they aren't part of the library.)
2447    Version 3.8 18-Dec-01
2448    ---------------------
2450    1. The experimental UTF-8 code was completely screwed up. It was packing the
2451    bytes in the wrong order. How dumb can you get?
2454    Version 3.7 29-Oct-01
2455    ---------------------
2457    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2458    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2459    this didn't happen under Solaris 8, where I normally test things.
2461    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2462    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2463    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2464    this fix an hour or so after the initial 3.7 release.)
2467    Version 3.6 23-Oct-01
2468    ---------------------
2470    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2471    offsets passed as NULL with zero offset count.
2473    2. The config.guess and config.sub files had not been updated when I moved to
2474    the latest autoconf.
2477    Version 3.5 15-Aug-01
2478    ---------------------
2480    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2481    had been forgotten.
2483    2. By using declared but undefined structures, we can avoid using "void"
2484    definitions in pcre.h while keeping the internal definitions of the structures
2485    private.
2487    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2488    user point of view, this means that both static and shared libraries are built
2489    by default, but this can be individually controlled. More of the work of
2490    handling this static/shared cases is now inside libtool instead of PCRE's make
2491    file.
2493    4. The pcretest utility is now installed along with pcregrep because it is
2494    useful for users (to test regexs) and by doing this, it automatically gets
2495    relinked by libtool. The documentation has been turned into a man page, so
2496    there are now .1, .txt, and .html versions in /doc.
2498    5. Upgrades to pcregrep:
2499       (i)   Added long-form option names like gnu grep.
2500       (ii)  Added --help to list all options with an explanatory phrase.
2501       (iii) Added -r, --recursive to recurse into sub-directories.
2502       (iv)  Added -f, --file to read patterns from a file.
2504    6. pcre_exec() was referring to its "code" argument before testing that
2505    argument for NULL (and giving an error if it was NULL).
2507    7. Upgraded Makefile.in to allow for compiling in a different directory from
2508    the source directory.
2510    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2511    options bits, the pointer it was passed was to an int instead of to an unsigned
2512    long int. This mattered only on 64-bit systems.
2514    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2515    generated) instead of pcre.in, which it its source. Also made the same change
2516    in several of the .c files.
2518    10. A new release of gcc defines printf() as a macro, which broke pcretest
2519    because it had an ifdef in the middle of a string argument for printf(). Fixed
2520    by using separate calls to printf().
2522    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2523    script, to force use of CR or LF instead of \n in the source. On non-Unix
2524    systems, the value can be set in config.h.
2526    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2527    absolute limit. Changed the text of the error message to make this clear, and
2528    likewise updated the man page.
2530    13. The limit of 99 on the number of capturing subpatterns has been removed.
2531    The new limit is 65535, which I hope will not be a "real" limit.
2534    Version 3.4 22-Aug-00
2535    ---------------------
2537    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2539    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2542    Version 3.3 01-Aug-00
2543    ---------------------
2545    1. If an octal character was given, but the value was greater than \377, it
2546    was not getting masked to the least significant bits, as documented. This could
2547    lead to crashes in some systems.
2549    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2550    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2552    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2553    These just pass their arguments on to (pcre_free)(), but they are provided
2554    because some uses of PCRE bind it to non-C systems that can call its functions,
2555    but cannot call free() or pcre_free() directly.
2557    4. Add "make test" as a synonym for "make check". Corrected some comments in
2558    the Makefile.
2560    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2561    Makefile.
2563    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2564    command called pgrep for grepping around the active processes.
2566    7. Added the beginnings of support for UTF-8 character strings.
2568    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2569    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2570    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2571    out for the ar command.)
2574    Version 3.2 12-May-00
2575    ---------------------
2577    This is purely a bug fixing release.
2579    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2580    of ZA. This was just one example of several cases that could provoke this bug,
2581    which was introduced by change 9 of version 2.00. The code for breaking
2582    infinite loops after an iteration that matches an empty string was't working
2583    correctly.
2585    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2586    when matched against abbab (for example). After matching an empty string, it
2587    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2588    caused it to match further down the string than it should.
2590    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2591    was there because it doesn't seem to be needed, and it causes trouble on some
2592    systems, as it is not a Standard C header. It has been removed.
2594    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2595    were reported on the Macintosh. The changes were from
2597      while ((c = *(++ptr)) != 0 && c != '\n');
2598    to
2599      while ((c = *(++ptr)) != 0 && c != '\n') ;
2601    Totally extraordinary, but if that's what it takes...
2603    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2604    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2605    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2606    assumes the way PCRE uses memmove() (always moving upwards).
2608    6. PCRE is being used in one environment where strchr() is not available. There
2609    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2610    faster code anyway.
2613    Version 3.1 09-Feb-00
2614    ---------------------
2616    The only change in this release is the fixing of some bugs in Makefile.in for
2617    the "install" target:
2619    (1) It was failing to install pcreposix.h.
2621    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2624    Version 3.0 01-Feb-00
2625    ---------------------
2627    1. Add support for the /+ modifier to perltest (to output $` like it does in
2628    pcretest).
2630    2. Add support for the /g modifier to perltest.
2632    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2633    matches null strings.
2635    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2636    pattern. Perl treats empty patterns specially - it reuses the most recent
2637    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2638    effect.
2640    5. The POSIX interface was broken in that it was just handing over the POSIX
2641    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2642    required a bigger vector, with some working space on the end. This means that
2643    the POSIX wrapper now has to get and free some memory, and copy the results.
2645    6. Added some simple autoconf support, placing the test data and the
2646    documentation in separate directories, re-organizing some of the
2647    information files, and making it build pcre-config (a GNU standard). Also added
2648    libtool support for building PCRE as a shared library, which is now the
2649    default.
2651    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2652    09 are not valid octal constants. Single digits will be used for minor values
2653    less than 10.
2655    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2656    existing programs that set these in the POSIX interface can use PCRE without
2657    modification.
2659    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2660    return all that pcre_info() returns, plus additional data. The pcre_info()
2661    function is retained for compatibility, but is considered to be obsolete.
2663    10. Added experimental recursion feature (?R) to handle one common case that
2664    Perl 5.6 will be able to do with (?p{...}).
2666    11. Added support for POSIX character classes like [:alpha:], which Perl is
2667    adopting.
2670    Version 2.08 31-Aug-99
2671    ----------------------
2673    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2674    trying to match at the startoffset position, but instead was moving forward to
2675    the next newline as if a previous match had failed.
2677    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2678    and could get into a loop if a null string was matched other than at the start
2679    of the subject.
2681    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2682    be distinguished at compile time, and for completeness also added PCRE_DATE.
2684    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2685    in GnuWin32 environments.
2688    Version 2.07 29-Jul-99
2689    ----------------------
2691    1. The documentation is now supplied in plain text form and HTML as well as in
2692    the form of man page sources.
2694    2. C++ compilers don't like assigning (void *) values to other pointer types.
2695    In particular this affects malloc(). Although there is no problem in Standard
2696    C, I've put in casts to keep C++ compilers happy.
2698    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2699    should be (const char *).
2701    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2702    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2703    However, I haven't made this a standard facility. The documentation doesn't
2704    mention it, and the Makefile doesn't support it.
2706    5. The Makefile now contains an "install" target, with editable destinations at
2707    the top of the file. The pcretest program is not installed.
2709    6. pgrep -V now gives the PCRE version number and date.
2711    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2712    causing the entire string to be ignored, instead of just the last character.
2714    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2715    non-matching string, it can take a very, very long time, even for strings of
2716    quite modest length, because of the nested recursion. PCRE now does better in
2717    some of these cases. It does this by remembering the last required literal
2718    character in the pattern, and pre-searching the subject to ensure it is present
2719    before running the real match. In other words, it applies a heuristic to detect
2720    some types of certain failure quickly, and in the above example, if presented
2721    with a string that has no trailing " it gives "no match" very quickly.
2723    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2724    other alternatives are tried instead.
2727    Version 2.06 09-Jun-99
2728    ----------------------
2730    1. Change pcretest's output for amount of store used to show just the code
2731    space, because the remainder (the data block) varies in size between 32-bit and
2732    64-bit systems.
2734    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2735    start matching at. This allows lookbehinds to work when searching for multiple
2736    occurrences in a string.
2738    3. Added additional options to pcretest for testing multiple occurrences:
2740       /+   outputs the rest of the string that follows a match
2741       /g   loops for multiple occurrences, using the new startoffset argument
2742       /G   loops for multiple occurrences by passing an incremented pointer
2744    4. PCRE wasn't doing the "first character" optimization for patterns starting
2745    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2746    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2747    the letter 'x'. On long subject strings, this gives a significant speed-up.
2750    Version 2.05 21-Apr-99
2751    ----------------------
2753    1. Changed the type of magic_number from int to long int so that it works
2754    properly on 16-bit systems.
2756    2. Fixed a bug which caused patterns starting with .* not to work correctly
2757    when the subject string contained newline characters. PCRE was assuming
2758    anchoring for such patterns in all cases, which is not correct because .* will
2759    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2760    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2761    must be retried after every newline in the subject.
2764    Version 2.04 18-Feb-99
2765    ----------------------
2767    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2768    computation of the store needed to hold the pattern was incorrect (too large).
2769    If such patterns were nested a few deep, this could multiply and become a real
2770    problem.
2772    2. Added /M option to pcretest to show the memory requirement of a specific
2773    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2775    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2776    compiled in such a way that the backtracking after subsequent failure was
2777    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2778    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2781    Version 2.03 02-Feb-99
2782    ----------------------
2784    1. Fixed typo and small mistake in man page.
2786    2. Added 4th condition (GPL supersedes if conflict) and created separate
2787    LICENCE file containing the conditions.
2789    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2790    Perl, that is the internal \ allows the delimiter to be included in the
2791    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2792    the final delimiter, add \ to the end of the pattern (to test the error).
2794    4. Added the convenience functions for extracting substrings after a successful
2795    match. Updated pcretest to make it able to test these functions.
2798    Version 2.02 14-Jan-99
2799    ----------------------
2801    1. Initialized the working variables associated with each extraction so that
2802    their saving and restoring doesn't refer to uninitialized store.
2804    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2805    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2806    fix the problem.
2808    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2809    calls, and wasn't printing the correct value for compiling calls. Increased the
2810    default value of LOOPREPEAT, and the number of significant figures in the
2811    times.
2813    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2815    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2816    a building problem on Windows NT with a FAT file system.
2819  Version 2.01 21-Oct-98  Version 2.01 21-Oct-98
2820  ----------------------  ----------------------

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