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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
45    9.  (*MARK) control verb is now supported by the JIT compiler.
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
58    13. (*COMMIT) is now correctly confined to within a recursive subpattern call.
61    Version 8.30 04-February-2012
62    -----------------------------
64    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
65        name is defined in ctype.h.
67    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
68        only in quite long subpatterns.
70    3.  Removed the function pcre_info(), which has been obsolete and deprecated
71        since it was replaced by pcre_fullinfo() in February 2000.
73    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
74        match a (*MARK), and the match failed at the start of the subject, a
75        reference to memory before the start of the subject could occur. This bug
76        was introduced by fix 17 of release 8.21.
78    5.  A reference to an unset group with zero minimum repetition was giving
79        totally wrong answers (in non-JavaScript-compatibility mode). For example,
80        /(another)?(\1?)test/ matched against "hello world test". This bug was
81        introduced in release 8.13.
83    6.  Add support for 16-bit character strings (a large amount of work involving
84        many changes and refactorings).
86    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
87        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
88        from a file.
90    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
91        rounding is not applied in this particular case).
93    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
94        if they appear, or are escaped, in patterns.
96    10. Get rid of a number of -Wunused-but-set-variable warnings.
98    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
99        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
100        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
101        also returns the mark "x". This bug applied to capturing parentheses,
102        non-capturing parentheses, and atomic parentheses. It also applied to some
103        assertions.
105    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
106        information out of configure.ac instead of relying on pcre.h.generic, which
107        is not stored in the repository.
109    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
110        -lreadline.
112    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
114    15. Applied Graycode's patch to put the top-level frame on the stack rather
115        than the heap when not using the stack for recursion. This gives a
116        performance improvement in many cases when recursion is not deep.
118    16. Experimental code added to "pcretest -C" to output the stack frame size.
121    Version 8.21 12-Dec-2011
122    ------------------------
124    1.  Updating the JIT compiler.
126    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
127        are added as well.
129    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
130        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
131        calling _pcre_jit_exec. Some extra comments are added.
133    4.  (*MARK) settings inside atomic groups that do not contain any capturing
134        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
135        was introduced by change 18 for 8.20.
137    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
138        ECMA-262 standard.
140    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
141        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
142        This bug was probably introduced by change 9 of 8.13.
144    7.  While fixing 6 above, I noticed that a number of other items were being
145        incorrectly rejected as "not fixed length". This arose partly because newer
146        opcodes had not been added to the fixed-length checking code. I have (a)
147        corrected the bug and added tests for these items, and (b) arranged for an
148        error to occur if an unknown opcode is encountered while checking for fixed
149        length instead of just assuming "not fixed length". The items that were
150        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
151        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
152        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
154    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
155        being incorrectly compiled and would have given unpredicatble results.
157    9.  A possessively repeated subpattern with minimum repeat count greater than
158        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
159        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
160        the first (A) could occur when it should not.
162    10. Add a cast and remove a redundant test from the code.
164    11. JIT should use pcre_malloc/pcre_free for allocation.
166    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
167        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
168        is anything other than /usr, -L is still shown).
170    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
172    14. Perl does not support \N without a following name in a [] class; PCRE now
173        also gives an error.
175    15. If a forward reference was repeated with an upper limit of around 2000,
176        it caused the error "internal error: overran compiling workspace". The
177        maximum number of forward references (including repeats) was limited by the
178        internal workspace, and dependent on the LINK_SIZE. The code has been
179        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
180        the default depends on LINK_SIZE. There is a new upper limit (for safety)
181        of around 200,000 forward references. While doing this, I also speeded up
182        the filling in of repeated forward references.
184    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
185        incorrectly expecting the subject to contain another "a" after the start.
187    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
188        in the match, the SKIP should be ignored. This was not happening; instead
189        the SKIP was being treated as NOMATCH. For patterns such as
190        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
191        tested.
193    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
194        now much more compatible with Perl, in particular in cases where the result
195        is a non-match for a non-anchored pattern. For example, if
196        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
197        "m", where previously it did not return a name. A side effect of this
198        change is that for partial matches, the last encountered mark name is
199        returned, as for non matches. A number of tests that were previously not
200        Perl-compatible have been moved into the Perl-compatible test files. The
201        refactoring has had the pleasing side effect of removing one argument from
202        the match() function, thus reducing its stack requirements.
204    19. If the /S+ option was used in pcretest to study a pattern using JIT,
205        subsequent uses of /S (without +) incorrectly behaved like /S+.
207    21. Retrieve executable code size support for the JIT compiler and fixing
208        some warnings.
210    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
211        not work when the shorter character appeared right at the end of the
212        subject string.
214    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
215        systems.
217    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
218        output it when the /M option is used in pcretest.
220    25. The CheckMan script was not being included in the distribution. Also, added
221        an explicit "perl" to run Perl scripts from the PrepareRelease script
222        because this is reportedly needed in Windows.
224    26. If study data was being save in a file and studying had not found a set of
225        "starts with" bytes for the pattern, the data written to the file (though
226        never used) was taken from uninitialized memory and so caused valgrind to
227        complain.
229    27. Updated RunTest.bat as provided by Sheri Pierce.
231    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
233    29. Computation of memory usage for the table of capturing group names was
234        giving an unnecessarily large value.
237    Version 8.20 21-Oct-2011
238    ------------------------
240    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
241        a POSIX class. After further experiments with Perl, which convinced me that
242        Perl has bugs and confusions, a closing square bracket is no longer allowed
243        in a POSIX name. This bug also affected patterns with classes that started
244        with full stops.
246    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
247        captured substring, but while checking the failing first alternative,
248        substring 1 is temporarily captured. If the output vector supplied to
249        pcre_exec() was not big enough for this capture, the yield of the function
250        was still zero ("insufficient space for captured substrings"). This cannot
251        be totally fixed without adding another stack variable, which seems a lot
252        of expense for a edge case. However, I have improved the situation in cases
253        such as /(a)(b)x|abc/ matched against "abc", where the return code
254        indicates that fewer than the maximum number of slots in the ovector have
255        been set.
257    3.  Related to (2) above: when there are more back references in a pattern than
258        slots in the output vector, pcre_exec() uses temporary memory during
259        matching, and copies in the captures as far as possible afterwards. It was
260        using the entire output vector, but this conflicts with the specification
261        that only 2/3 is used for passing back captured substrings. Now it uses
262        only the first 2/3, for compatibility. This is, of course, another edge
263        case.
265    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
266        main code base, and can be used by building with --enable-jit. When this is
267        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
268        runtime --no-jit option is given.
270    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
271        ovector, the return from the function was zero, implying that there were
272        other matches that did not fit. The correct "exactly full" value is now
273        returned.
275    6.  If a subpattern that was called recursively or as a subroutine contained
276        (*PRUNE) or any other control that caused it to give a non-standard return,
277        invalid errors such as "Error -26 (nested recursion at the same subject
278        position)" or even infinite loops could occur.
280    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
281        computing the minimum length on reaching *ACCEPT, and so ended up with the
282        wrong value of 1 rather than 0. Further investigation indicates that
283        computing a minimum subject length in the presence of *ACCEPT is difficult
284        (think back references, subroutine calls), and so I have changed the code
285        so that no minimum is registered for a pattern that contains *ACCEPT.
287    8.  If (*THEN) was present in the first (true) branch of a conditional group,
288        it was not handled as intended. [But see 16 below.]
290    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
291        Sheri Pierce.
293    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
294        the first byte in a match must be "a".
296    11. Change 17 for 8.13 increased the recursion depth for patterns like
297        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
298        pattern contains any instances of (*THEN). If it does not, the old
299        optimizations are restored. It would be nice to do this on a per-group
300        basis, but at the moment that is not feasible.
302    12. In some environments, the output of pcretest -C is CRLF terminated. This
303        broke RunTest's code that checks for the link size. A single white space
304        character after the value is now allowed for.
306    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
307        For "fr", it uses the Windows-specific input and output files.
309    14. If (*THEN) appeared in a group that was called recursively or as a
310        subroutine, it did not work as intended. [But see next item.]
312    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
313        pattern fragments (but not containing any | characters). If A and B are
314        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
315        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
316        D. In other words, Perl considers parentheses that do not contain any |
317        characters to be part of a surrounding alternative, whereas PCRE was
318        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
319        differently. PCRE now behaves in the same way as Perl, except in the case
320        of subroutine/recursion calls such as (?1) which have in any case always
321        been different (but PCRE had them first :-).
323    16. Related to 15 above: Perl does not treat the | in a conditional group as
324        creating alternatives. Such a group is treated in the same way as an
325        ordinary group without any | characters when processing (*THEN). PCRE has
326        been changed to match Perl's behaviour.
328    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
329        RunGrepTest script failed.
331    18. Change 22 for version 13 caused atomic groups to use more stack. This is
332        inevitable for groups that contain captures, but it can lead to a lot of
333        stack use in large patterns. The old behaviour has been restored for atomic
334        groups that do not contain any capturing parentheses.
336    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
337        suppress the check for a minimum subject length at run time. (If it was
338        given to pcre_exec() or pcre_dfa_exec() it did work.)
340    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
341        fail to work when decoding hex characters in data strings in EBCDIC
342        environments.
344    21. It appears that in at least one Mac OS environment, the isxdigit() function
345        is implemented as a macro that evaluates to its argument more than once,
346        contravening the C 90 Standard (I haven't checked a later standard). There
347        was an instance in pcretest which caused it to go wrong when processing
348        \x{...} escapes in subject strings. The has been rewritten to avoid using
349        things like p++ in the argument of isxdigit().
352    Version 8.13 16-Aug-2011
353    ------------------------
355    1.  The Unicode data tables have been updated to Unicode 6.0.0.
357    2.  Two minor typos in pcre_internal.h have been fixed.
359    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
360        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
361        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
363    4.  There were a number of related bugs in the code for matching backrefences
364        caselessly in UTF-8 mode when codes for the characters concerned were
365        different numbers of bytes. For example, U+023A and U+2C65 are an upper
366        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
367        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
368        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
369        2-byte code at the end of the subject (it thought there wasn't enough data
370        left).
372    5.  Comprehensive information about what went wrong is now returned by
373        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
374        as the output vector has at least 2 elements. The offset of the start of
375        the failing character and a reason code are placed in the vector.
377    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
378        now returned is for the first byte of the failing character, instead of the
379        last byte inspected. This is an incompatible change, but I hope it is small
380        enough not to be a problem. It makes the returned offset consistent with
381        pcre_exec() and pcre_dfa_exec().
383    7.  pcretest now gives a text phrase as well as the error number when
384        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
385        failure, the offset and reason code are output.
387    8.  When \R was used with a maximizing quantifier it failed to skip backwards
388        over a \r\n pair if the subsequent match failed. Instead, it just skipped
389        back over a single character (\n). This seems wrong (because it treated the
390        two characters as a single entity when going forwards), conflicts with the
391        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
392        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
393        has been changed.
395    9.  Some internal refactoring has changed the processing so that the handling
396        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
397        time (the PCRE_DOTALL option was changed this way some time ago: version
398        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
399        which was always a bit of a fudge. It also means that there is one less
400        argument for the match() function, which reduces its stack requirements
401        slightly. This change also fixes an incompatibility with Perl: the pattern
402        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
404    10. More internal refactoring has drastically reduced the number of recursive
405        calls to match() for possessively repeated groups such as (abc)++ when
406        using pcre_exec().
408    11. While implementing 10, a number of bugs in the handling of groups were
409        discovered and fixed:
411        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
412        (a|)*(?1) gave a compile-time internal error.
413        ((a|)+)+  did not notice that the outer group could match an empty string.
414        (^a|^)+   was not marked as anchored.
415        (.*a|.*)+ was not marked as matching at start or after a newline.
417    12. Yet more internal refactoring has removed another argument from the match()
418        function. Special calls to this function are now indicated by setting a
419        value in a variable in the "match data" data block.
421    13. Be more explicit in pcre_study() instead of relying on "default" for
422        opcodes that mean there is no starting character; this means that when new
423        ones are added and accidentally left out of pcre_study(), testing should
424        pick them up.
426    14. The -s option of pcretest has been documented for ages as being an old
427        synonym of -m (show memory usage). I have changed it to mean "force study
428        for every regex", that is, assume /S for every regex. This is similar to -i
429        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
430        using it. It makes it easier to run collections of tests with and without
431        study enabled, and thereby test pcre_study() more easily. All the standard
432        tests are now run with and without -s (but some patterns can be marked as
433        "never study" - see 20 below).
435    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
436        restoration of the capturing data to the outer values was not happening
437        correctly.
439    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
440        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
441        pattern had matched an empty string, and so incorrectly returned a no
442        match.
444    17. There was optimizing code for the last branch of non-capturing parentheses,
445        and also for the obeyed branch of a conditional subexpression, which used
446        tail recursion to cut down on stack usage. Unfortunately, now that there is
447        the possibility of (*THEN) occurring in these branches, tail recursion is
448        no longer possible because the return has to be checked for (*THEN). These
449        two optimizations have therefore been removed. [But see 8.20/11 above.]
451    18. If a pattern containing \R was studied, it was assumed that \R always
452        matched two bytes, thus causing the minimum subject length to be
453        incorrectly computed because \R can also match just one byte.
455    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
456        was incorrectly computed.
458    20. If /S is present twice on a test pattern in pcretest input, it now
459        *disables* studying, thereby overriding the use of -s on the command line
460        (see 14 above). This is necessary for one or two tests to keep the output
461        identical in both cases.
463    21. When (*ACCEPT) was used in an assertion that matched an empty string and
464        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
466    22. When an atomic group that contained a capturing parenthesis was
467        successfully matched, but the branch in which it appeared failed, the
468        capturing was not being forgotten if a higher numbered group was later
469        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
470        group 1 to "a", when in fact it should be unset. This applied to multi-
471        branched capturing and non-capturing groups, repeated or not, and also to
472        positive assertions (capturing in negative assertions does not happen
473        in PCRE) and also to nested atomic groups.
475    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
476        subject after a captured substring, to make it easier to tell which of a
477        number of identical substrings has been captured.
479    24. The way atomic groups are processed by pcre_exec() has been changed so that
480        if they are repeated, backtracking one repetition now resets captured
481        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
482        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
483        "aaa". Previously, it would have been "a". As part of this code
484        refactoring, the way recursive calls are handled has also been changed.
486    25. If an assertion condition captured any substrings, they were not passed
487        back unless some other capturing happened later. For example, if
488        (?(?=(a))a) was matched against "a", no capturing was returned.
490    26. When studying a pattern that contained subroutine calls or assertions,
491        the code for finding the minimum length of a possible match was handling
492        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
493        group 1 called group 2 while simultaneously a separate group 2 called group
494        1). A stack overflow occurred in this case. I have fixed this by limiting
495        the recursion depth to 10.
497    27. Updated RunTest.bat in the distribution to the version supplied by Tom
498        Fortmann. This supports explicit test numbers on the command line, and has
499        argument validation and error reporting.
501    28. An instance of \X with an unlimited repeat could fail if at any point the
502        first character it looked at was a mark character.
504    29. Some minor code refactoring concerning Unicode properties and scripts
505        should reduce the stack requirement of match() slightly.
507    30. Added the '=' option to pcretest to check the setting of unused capturing
508        slots at the end of the pattern, which are documented as being -1, but are
509        not included in the return count.
511    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
512        compiled something random. Now it gives a compile-time error (as does
513        Perl).
515    32. A *MARK encountered during the processing of a positive assertion is now
516        recorded and passed back (compatible with Perl).
518    33. If --only-matching or --colour was set on a pcregrep call whose pattern
519        had alternative anchored branches, the search for a second match in a line
520        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
521        matched the line "0102" twice. The same bug affected patterns that started
522        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
523        twice.
525    34. Previously, PCRE did not allow quantification of assertions. However, Perl
526        does, and because of capturing effects, quantifying parenthesized
527        assertions may at times be useful. Quantifiers are now allowed for
528        parenthesized assertions.
530    35. A minor code tidy in pcre_compile() when checking options for \R usage.
532    36. \g was being checked for fancy things in a character class, when it should
533        just be a literal "g".
535    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
536        appearance of a nested POSIX class supersedes an apparent external class.
537        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
538        unescaped square brackets may also appear as part of class names. For
539        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
540        more like Perl. (But see 8.20/1 above.)
542    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
543        was because it thought it was \N{name}, which is not supported).
545    39. Add minix to OS list not supporting the -S option in pcretest.
547    40. PCRE tries to detect cases of infinite recursion at compile time, but it
548        cannot analyze patterns in sufficient detail to catch mutual recursions
549        such as ((?1))((?2)). There is now a runtime test that gives an error if a
550        subgroup is called recursively as a subpattern for a second time at the
551        same position in the subject string. In previous releases this might have
552        been caught by the recursion limit, or it might have run out of stack.
554    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
555        happen only once. PCRE was, however incorrectly giving a compile time error
556        "recursive call could loop indefinitely" because it cannot analyze the
557        pattern in sufficient detail. The compile time test no longer happens when
558        PCRE is compiling a conditional subpattern, but actual runaway loops are
559        now caught at runtime (see 40 above).
561    42. It seems that Perl allows any characters other than a closing parenthesis
562        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
563        has been changed to be the same.
565    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
566        as not to get warnings when autogen.sh is called. Also changed
567        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
569    44. To help people who use pcregrep to scan files containing exceedingly long
570        lines, the following changes have been made:
572        (a) The default value of the buffer size parameter has been increased from
573            8K to 20K. (The actual buffer used is three times this size.)
575        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
576            PCRE is built.
578        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
579            to be set at run time.
581        (d) Numerical values in pcregrep options can be followed by K or M, for
582            example --buffer-size=50K.
584        (e) If a line being scanned overflows pcregrep's buffer, an error is now
585            given and the return code is set to 2.
587    45. Add a pointer to the latest mark to the callout data block.
589    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
590        partial match of an empty string instead of no match. This was specific to
591        the use of ".".
593    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
594        complete match instead of a partial match. This bug was dependent on both
595        the PCRE_UTF8 and PCRE_DOTALL options being set.
597    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
598        starting byte set, because \b was not being ignored.
601    Version 8.12 15-Jan-2011
602    ------------------------
604    1.  Fixed some typos in the markup of the man pages, and wrote a script that
605        checks for such things as part of the documentation building process.
607    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
608        --match-limit and --recursion-limit options (added for 8.11). In
609        particular, this made one of the standard tests fail. (The integer value
610        went into the wrong half of a long int.)
612    3.  If the --colour option was given to pcregrep with -v (invert match), it
613        did strange things, either producing crazy output, or crashing. It should,
614        of course, ignore a request for colour when reporting lines that do not
615        match.
617    4.  Another pcregrep bug caused similar problems if --colour was specified with
618        -M (multiline) and the pattern match finished with a line ending.
620    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
621        matched in multiline mode, the following line was shown as part of the
622        match. This seems wrong, so I have changed it.
624    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
625        the check for further matches in the same line (so they could be coloured)
626        to overrun the end of the current line. If another match was found, it was
627        incorrectly shown (and then shown again when found in the next line).
629    7.  If pcregrep was compiled under Windows, there was a reference to the
630        function pcregrep_exit() before it was defined. I am assuming this was
631        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
632        reported by a user. I've moved the definition above the reference.
635    Version 8.11 10-Dec-2010
636    ------------------------
638    1.  (*THEN) was not working properly if there were untried alternatives prior
639        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
640        backtracked to try for "b" instead of moving to the next alternative branch
641        at the same level (in this case, to look for "c"). The Perl documentation
642        is clear that when (*THEN) is backtracked onto, it goes to the "next
643        alternative in the innermost enclosing group".
645    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
646        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
647        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
648        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
649        (*THEN).
651    3.  If \s appeared in a character class, it removed the VT character from
652        the class, even if it had been included by some previous item, for example
653        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
654        of \s, but is part of the POSIX "space" class.)
656    4.  A partial match never returns an empty string (because you can always
657        match an empty string at the end of the subject); however the checking for
658        an empty string was starting at the "start of match" point. This has been
659        changed to the "earliest inspected character" point, because the returned
660        data for a partial match starts at this character. This means that, for
661        example, /(?<=abc)def/ gives a partial match for the subject "abc"
662        (previously it gave "no match").
664    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
665        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
666        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
667        has an implication that the given string is incomplete (because a partial
668        match is preferred over a full match). For this reason, these items now
669        give a partial match in this situation. [Aside: previously, the one case
670        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
671        match rather than a full match, which was wrong by the old rules, but is
672        now correct.]
674    6.  There was a bug in the handling of #-introduced comments, recognized when
675        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
676        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
677        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
678        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
679        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
680        places in pcre_compile().
682    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
683        comments when looking ahead for named forward references to subpatterns,
684        the only newline sequence it recognized was NL. It now handles newlines
685        according to the set newline convention.
687    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
688        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
689        cater for a lack of strerror(). These oversights have been fixed.
691    9.  Added --match-limit and --recursion-limit to pcregrep.
693    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
695    11. When the -o option was used, pcregrep was setting a return code of 1, even
696        when matches were found, and --line-buffered was not being honoured.
698    12. Added an optional parentheses number to the -o and --only-matching options
699        of pcregrep.
701    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
702        can match an empty string. The code to do it in pcretest and pcredemo
703        needed fixing:
705        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
706            only one byte after an empty string match just before CRLF (this case
707            just got forgotten; "any" and "anycrlf" were OK).
709        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
710            mode when an empty string match preceded an ASCII character followed by
711            a non-ASCII character. (The code for advancing by one character rather
712            than one byte was nonsense.)
714        (c) The pcredemo.c sample program did not have any code at all to handle
715            the cases when CRLF is a valid newline sequence.
717    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
718        as a starting offset was within the subject string. There is now a new
719        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
720        negative or greater than the length of the string. In order to test this,
721        pcretest is extended to allow the setting of negative starting offsets.
723    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
724        starting offset points to the beginning of a UTF-8 character was
725        unnecessarily clumsy. I tidied it up.
727    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
728        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
730    17. Nobody had reported that the --include_dir option, which was added in
731        release 7.7 should have been called --include-dir (hyphen, not underscore)
732        for compatibility with GNU grep. I have changed it to --include-dir, but
733        left --include_dir as an undocumented synonym, and the same for
734        --exclude-dir, though that is not available in GNU grep, at least as of
735        release 2.5.4.
737    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
738        characters from a string of bytes) have been redefined so as not to use
739        loops, in order to improve performance in some environments. At the same
740        time, I abstracted some of the common code into auxiliary macros to save
741        repetition (this should not affect the compiled code).
743    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
744        compile-time error is now given if \c is not followed by an ASCII
745        character, that is, a byte less than 128. (In EBCDIC mode, the code is
746        different, and any byte value is allowed.)
748    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
749        START_OPTIMIZE option, which is now allowed at compile time - but just
750        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
751        to pcregrep and other applications that have no direct access to PCRE
752        options. The new /Y option in pcretest sets this option when calling
753        pcre_compile().
755    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
756        back references. Groups containing recursive back references were forced to
757        be atomic by that change, but in the case of named groups, the amount of
758        memory required was incorrectly computed, leading to "Failed: internal
759        error: code overflow". This has been fixed.
761    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
762        pcretest.c, to avoid build problems in some Borland environments.
765    Version 8.10 25-Jun-2010
766    ------------------------
768    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
769        THEN.
771    2.  (*ACCEPT) was not working when inside an atomic group.
773    3.  Inside a character class, \B is treated as a literal by default, but
774        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
775        causes the error). The code is unchanged, but I tidied the documentation.
777    4.  Inside a character class, PCRE always treated \R and \X as literals,
778        whereas Perl faults them if its -w option is set. I have changed PCRE so
779        that it faults them when PCRE_EXTRA is set.
781    5.  Added support for \N, which always matches any character other than
782        newline. (It is the same as "." when PCRE_DOTALL is not set.)
784    6.  When compiling pcregrep with newer versions of gcc which may have
785        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
786        declared with attribute warn_unused_result" were given. Just casting the
787        result to (void) does not stop the warnings; a more elaborate fudge is
788        needed. I've used a macro to implement this.
790    7.  Minor change to pcretest.c to avoid a compiler warning.
792    8.  Added four artifical Unicode properties to help with an option to make
793        \s etc use properties (see next item). The new properties are: Xan
794        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
796    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
797        use Unicode properties. (*UCP) at the start of a pattern can be used to set
798        this option. Modified pcretest to add /W to test this facility. Added
799        REG_UCP to make it available via the POSIX interface.
801    10. Added --line-buffered to pcregrep.
803    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
804        studied, and the match started with a letter with a code point greater than
805        127 whose first byte was different to the first byte of the other case of
806        the letter, the other case of this starting letter was not recognized
807        (#976).
809    12. If a pattern that was studied started with a repeated Unicode property
810        test, for example, \p{Nd}+, there was the theoretical possibility of
811        setting up an incorrect bitmap of starting bytes, but fortunately it could
812        not have actually happened in practice until change 8 above was made (it
813        added property types that matched character-matching opcodes).
815    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
816        possible starting bytes for non-anchored patterns.
818    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
819        \R, and also a number of cases that involve Unicode properties, both
820        explicit and implicit when PCRE_UCP is set.
822    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
823        input, it could crash or give wrong results if characters with values
824        greater than 0xc0 were present in the subject string. (Detail: it assumed
825        UTF-8 input when processing these items.)
827    16. Added a lot of (int) casts to avoid compiler warnings in systems where
828        size_t is 64-bit (#991).
830    17. Added a check for running out of memory when PCRE is compiled with
831        --disable-stack-for-recursion (#990).
833    18. If the last data line in a file for pcretest does not have a newline on
834        the end, a newline was missing in the output.
836    19. The default pcre_chartables.c file recognizes only ASCII characters (values
837        less than 128) in its various bitmaps. However, there is a facility for
838        generating tables according to the current locale when PCRE is compiled. It
839        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
840        characters, are recognized by isspace() and therefore were getting set in
841        these tables, and indeed these tables seem to approximate to ISO 8859. This
842        caused a problem in UTF-8 mode when pcre_study() was used to create a list
843        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
844        which of course cannot start UTF-8 characters. I have changed the code so
845        that only real ASCII characters (less than 128) and the correct starting
846        bytes for UTF-8 encodings are set for characters greater than 127 when in
847        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
848        altogether.)
850    20. Added the /T option to pcretest so as to be able to run tests with non-
851        standard character tables, thus making it possible to include the tests
852        used for 19 above in the standard set of tests.
854    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
855        reference to a subpattern the other side of a comment that contains an
856        opening parenthesis caused either an internal compiling error, or a
857        reference to the wrong subpattern.
860    Version 8.02 19-Mar-2010
861    ------------------------
863    1.  The Unicode data tables have been updated to Unicode 5.2.0.
865    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
866        configured.
868    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
869        original author of that file, following a query about its status.
871    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
872        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
874    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
875        quantifier applied to a forward-referencing subroutine call, could compile
876        incorrect code or give the error "internal error: previously-checked
877        referenced subpattern not found".
879    6.  Both MS Visual Studio and Symbian OS have problems with initializing
880        variables to point to external functions. For these systems, therefore,
881        pcre_malloc etc. are now initialized to local functions that call the
882        relevant global functions.
884    7.  There were two entries missing in the vectors called coptable and poptable
885        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
886        I've fixed the data, and added a kludgy way of testing at compile time that
887        the lengths are correct (equal to the number of opcodes).
889    8.  Following on from 7, I added a similar kludge to check the length of the
890        eint vector in pcreposix.c.
892    9.  Error texts for pcre_compile() are held as one long string to avoid too
893        much relocation at load time. To find a text, the string is searched,
894        counting zeros. There was no check for running off the end of the string,
895        which could happen if a new error number was added without updating the
896        string.
898    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
900    11. \K was not working if it appeared in an atomic group or in a group that
901        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
902        \K is "not well defined" if used in an assertion. PCRE now accepts it if
903        the assertion is positive, but not if it is negative.
905    12. Change 11 fortuitously reduced the size of the stack frame used in the
906        "match()" function of pcre_exec.c by one pointer. Forthcoming
907        implementation of support for (*MARK) will need an extra pointer on the
908        stack; I have reserved it now, so that the stack frame size does not
909        decrease.
911    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
912        item in branch that calls a recursion is a subroutine call - as in the
913        second branch in the above example - was incorrectly given the compile-
914        time error "recursive call could loop indefinitely" because pcre_compile()
915        was not correctly checking the subroutine for matching a non-empty string.
917    14. The checks for overrunning compiling workspace could trigger after an
918        overrun had occurred. This is a "should never occur" error, but it can be
919        triggered by pathological patterns such as hundreds of nested parentheses.
920        The checks now trigger 100 bytes before the end of the workspace.
922    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
925    Version 8.01 19-Jan-2010
926    ------------------------
928    1.  If a pattern contained a conditional subpattern with only one branch (in
929        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
930        computed the wrong minimum data length (which is of course zero for such
931        subpatterns). This could cause incorrect "no match" results.
933    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
934        the pattern is reset in the first branch, pcre_compile() failed with
935        "internal error: code overflow at offset...". This happened only when
936        the reset was to the original external option setting. (An optimization
937        abstracts leading options settings into an external setting, which was the
938        cause of this.)
940    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
941        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
942        assertion pattern did not match (meaning that the assertion was true), it
943        was incorrectly treated as false if the SKIP had been reached during the
944        matching. This also applied to assertions used as conditions.
946    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
947        assertion subpattern, including such a pattern used as a condition,
948        unpredictable results occurred, instead of the error return
951    5.  The C++ GlobalReplace function was not working like Perl for the special
952        situation when an empty string is matched. It now does the fancy magic
953        stuff that is necessary.
955    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
956        removed. (These were left over from very, very early versions of PCRE.)
958    7.  Some cosmetic changes to the code to make life easier when compiling it
959        as part of something else:
961        (a) Change DEBUG to PCRE_DEBUG.
963        (b) In pcre_compile(), rename the member of the "branch_chain" structure
964            called "current" as "current_branch", to prevent a collision with the
965            Linux macro when compiled as a kernel module.
967        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
968            prevent a collision with the Linux macro when compiled as a kernel
969            module.
971    8.  In pcre_compile() there are some checks for integer overflows that used to
972        cast potentially large values to (double). This has been changed to that
973        when building, a check for int64_t is made, and if it is found, it is used
974        instead, thus avoiding the use of floating point arithmetic. (There is no
975        other use of FP in PCRE.) If int64_t is not found, the fallback is to
976        double.
978    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
979        2005 (difference between two addresses compared to an unsigned value).
981    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
982        custom one, because of the following reported problem in Windows:
984          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
985              under Win32.
986          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
987              therefore missing the function definition.
988          - The compiler thus generates a "C" signature for the test function.
989          - The linker fails to find the "C" function.
990          - PCRE fails to configure if asked to do so against libbz2.
992    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
993        messages were output:
995          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
996          rerunning libtoolize, to keep the correct libtool macros in-tree.
997          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
999        I have done both of these things.
1001    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1002        most of the time, it *can* run out if it is given a pattern that contains a
1003        runaway infinite recursion. I updated the discussion in the pcrestack man
1004        page.
1006    13. Now that we have gone to the x.xx style of version numbers, the minor
1007        version may start with zero. Using 08 or 09 is a bad idea because users
1008        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1009        interpreted as invalid octal numbers. I've updated the previous comment in
1010        configure.ac, and also added a check that gives an error if 08 or 09 are
1011        used.
1013    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1014        causing partial matching to fail when the end of the subject matched \W
1015        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1017    15. There were some discrepancies between the declarations in pcre_internal.h
1018        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1019        their definitions. The declarations used "const uschar *" and the
1020        definitions used USPTR. Even though USPTR is normally defined as "const
1021        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1022        reported that: "This difference in casting confuses some C++ compilers, for
1023        example, SunCC recognizes above declarations as different functions and
1024        generates broken code for hbpcre." I have changed the declarations to use
1025        USPTR.
1027    16. GNU libtool is named differently on some systems. The autogen.sh script now
1028        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1029        (FreeBSD).
1031    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1032        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1033        comment: "Figure out how to create a longlong from a string: strtoll and
1034        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1035        instance, but it only takes 2 args instead of 3!"
1037    18. A subtle bug concerned with back references has been fixed by a change of
1038        specification, with a corresponding code fix. A pattern such as
1039        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1040        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1041        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1042        same bug. Such groups have to be quantified to be useful, or contained
1043        inside another quantified group. (If there's no repetition, the reference
1044        can never match.) The problem arises because, having left the group and
1045        moved on to the rest of the pattern, a later failure that backtracks into
1046        the group uses the captured value from the final iteration of the group
1047        rather than the correct earlier one. I have fixed this in PCRE by forcing
1048        any group that contains a reference to itself to be an atomic group; that
1049        is, there cannot be any backtracking into it once it has completed. This is
1050        similar to recursive and subroutine calls.
1053    Version 8.00 19-Oct-09
1054  ----------------------  ----------------------
1056  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1057      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1058      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1059      error.      error.
1061    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1062        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1063        in a Windows environment.
1065    3.  The pcregrep --count option prints the count for each file even when it is
1066        zero, as does GNU grep. However, pcregrep was also printing all files when
1067        --files-with-matches was added. Now, when both options are given, it prints
1068        counts only for those files that have at least one match. (GNU grep just
1069        prints the file name in this circumstance, but including the count seems
1070        more useful - otherwise, why use --count?) Also ensured that the
1071        combination -clh just lists non-zero counts, with no names.
1073    4.  The long form of the pcregrep -F option was incorrectly implemented as
1074        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1075        but it seems right to fix it, and I didn't think it was worth preserving
1076        the old behaviour.
1078    5.  The command line items --regex=pattern and --regexp=pattern were not
1079        recognized by pcregrep, which required --regex pattern or --regexp pattern
1080        (with a space rather than an '='). The man page documented the '=' forms,
1081        which are compatible with GNU grep; these now work.
1083    6.  No libpcreposix.pc file was created for pkg-config; there was just
1084        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1086    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1087        when UCP support is not needed, by modifying the Python script that
1088        generates it from Unicode data files. This should not matter if the module
1089        is correctly used as a library, but I received one complaint about 50K of
1090        unwanted data. My guess is that the person linked everything into his
1091        program rather than using a library. Anyway, it does no harm.
1093    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1094        was a minimum greater than 1 for a wide character in a possessive
1095        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1096        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1097        character. Chaos in the form of incorrect output or a compiling loop could
1098        result.
1100    9.  The restrictions on what a pattern can contain when partial matching is
1101        requested for pcre_exec() have been removed. All patterns can now be
1102        partially matched by this function. In addition, if there are at least two
1103        slots in the offset vector, the offset of the earliest inspected character
1104        for the match and the offset of the end of the subject are set in them when
1105        PCRE_ERROR_PARTIAL is returned.
1107    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1108        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1109        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1110        and may be more useful for multi-segment matching.
1112    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1113        used to be given if ever the end of the subject was reached; now it is
1114        given only if matching could not proceed because another character was
1115        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1116        string "Z", which now yields "no match" instead of "partial match". In the
1117        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1118        final character ended with (*FAIL).
1120    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1121        if the pattern had a "must contain" character that was already found in the
1122        earlier partial match, unless partial matching was again requested. For
1123        example, with the pattern /dog.(body)?/, the "must contain" character is
1124        "g". If the first part-match was for the string "dog", restarting with
1125        "sbody" failed. This bug has been fixed.
1127    13. The string returned by pcre_dfa_exec() after a partial match has been
1128        changed so that it starts at the first inspected character rather than the
1129        first character of the match. This makes a difference only if the pattern
1130        starts with a lookbehind assertion or \b or \B (\K is not supported by
1131        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1132        matching functions compatible, and I think it's the right thing to do.
1134    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1135        so that the demonstration program is easily available in environments where
1136        PCRE has not been installed from source.
1138    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1139        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1140        library.
1142    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1143        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1144        is not the first non-POSIX option to be added. Clearly some people find
1145        these options useful.
1147    17. If a caller to the POSIX matching function regexec() passes a non-zero
1148        value for nmatch with a NULL value for pmatch, the value of
1149        nmatch is forced to zero.
1151    18. RunGrepTest did not have a test for the availability of the -u option of
1152        the diff command, as RunTest does. It now checks in the same way as
1153        RunTest, and also checks for the -b option.
1155    19. If an odd number of negated classes containing just a single character
1156        interposed, within parentheses, between a forward reference to a named
1157        subpattern and the definition of the subpattern, compilation crashed with
1158        an internal error, complaining that it could not find the referenced
1159        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1160        [The bug was that it was starting one character too far in when skipping
1161        over the character class, thus treating the ] as data rather than
1162        terminating the class. This meant it could skip too much.]
1164    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1165        /g option in pcretest when the pattern contains \K, which makes it possible
1166        to have an empty string match not at the start, even when the pattern is
1167        anchored. Updated pcretest and pcredemo to use this option.
1169    21. If the maximum number of capturing subpatterns in a recursion was greater
1170        than the maximum at the outer level, the higher number was returned, but
1171        with unset values at the outer level. The correct (outer level) value is
1172        now given.
1174    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1175        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1176        make it do so. The string so far is captured, making this feature
1177        compatible with Perl.
1179    23. The tests have been re-organized, adding tests 11 and 12, to make it
1180        possible to check the Perl 5.10 features against Perl 5.10.
1182    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1183        pattern matches a fixed length string. PCRE did not allow this; now it
1184        does. Neither allows recursion.
1186    25. I finally figured out how to implement a request to provide the minimum
1187        length of subject string that was needed in order to match a given pattern.
1188        (It was back references and recursion that I had previously got hung up
1189        on.) This code has now been added to pcre_study(); it finds a lower bound
1190        to the length of subject needed. It is not necessarily the greatest lower
1191        bound, but using it to avoid searching strings that are too short does give
1192        some useful speed-ups. The value is available to calling programs via
1193        pcre_fullinfo().
1195    26. While implementing 25, I discovered to my embarrassment that pcretest had
1196        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1197        study optimizations had never been tested with that matching function.
1198        Oops. What is worse, even when it was passed study data, there was a bug in
1199        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1200        were also very few tests of studied patterns with pcre_dfa_exec().
1202    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1203        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1204        on the other side of the coin, they are no longer allowed to have different
1205        names, because these cannot be distinguished in PCRE, and this has caused
1206        confusion. (This is a difference from Perl.)
1208    28. When duplicate subpattern names are present (necessarily with different
1209        numbers, as required by 27 above), and a test is made by name in a
1210        conditional pattern, either for a subpattern having been matched, or for
1211        recursion in such a pattern, all the associated numbered subpatterns are
1212        tested, and the overall condition is true if the condition is true for any
1213        one of them. This is the way Perl works, and is also more like the way
1214        testing by number works.
1217  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1218  ---------------------  ---------------------

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