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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.11 10-Oct-2010
5    ------------------------
6    
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
13    
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
19    
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
24    
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
32    
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
42    
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
50    
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
55    
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
59    
60    9.  Added --match-limit and --recursion-limit to pcregrep.
61    
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
63    
64    
65    Version 8.10 25-Jun-2010
66    ------------------------
67    
68    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
69        THEN.
70    
71    2.  (*ACCEPT) was not working when inside an atomic group.
72    
73    3.  Inside a character class, \B is treated as a literal by default, but
74        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
75        causes the error). The code is unchanged, but I tidied the documentation.
76    
77    4.  Inside a character class, PCRE always treated \R and \X as literals,
78        whereas Perl faults them if its -w option is set. I have changed PCRE so
79        that it faults them when PCRE_EXTRA is set.
80    
81    5.  Added support for \N, which always matches any character other than
82        newline. (It is the same as "." when PCRE_DOTALL is not set.)
83    
84    6.  When compiling pcregrep with newer versions of gcc which may have
85        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
86        declared with attribute warn_unused_result" were given. Just casting the
87        result to (void) does not stop the warnings; a more elaborate fudge is
88        needed. I've used a macro to implement this.
89    
90    7.  Minor change to pcretest.c to avoid a compiler warning.
91    
92    8.  Added four artifical Unicode properties to help with an option to make
93        \s etc use properties (see next item). The new properties are: Xan
94        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
95    
96    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
97        use Unicode properties. (*UCP) at the start of a pattern can be used to set
98        this option. Modified pcretest to add /W to test this facility. Added
99        REG_UCP to make it available via the POSIX interface.
100    
101    10. Added --line-buffered to pcregrep.
102    
103    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
104        studied, and the match started with a letter with a code point greater than
105        127 whose first byte was different to the first byte of the other case of
106        the letter, the other case of this starting letter was not recognized
107        (#976).
108    
109    12. If a pattern that was studied started with a repeated Unicode property
110        test, for example, \p{Nd}+, there was the theoretical possibility of
111        setting up an incorrect bitmap of starting bytes, but fortunately it could
112        not have actually happened in practice until change 8 above was made (it
113        added property types that matched character-matching opcodes).
114    
115    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
116        possible starting bytes for non-anchored patterns.
117    
118    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
119        \R, and also a number of cases that involve Unicode properties, both
120        explicit and implicit when PCRE_UCP is set.
121    
122    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
123        input, it could crash or give wrong results if characters with values
124        greater than 0xc0 were present in the subject string. (Detail: it assumed
125        UTF-8 input when processing these items.)
126    
127    16. Added a lot of (int) casts to avoid compiler warnings in systems where
128        size_t is 64-bit (#991).
129    
130    17. Added a check for running out of memory when PCRE is compiled with
131        --disable-stack-for-recursion (#990).
132    
133    18. If the last data line in a file for pcretest does not have a newline on
134        the end, a newline was missing in the output.
135    
136    19. The default pcre_chartables.c file recognizes only ASCII characters (values
137        less than 128) in its various bitmaps. However, there is a facility for
138        generating tables according to the current locale when PCRE is compiled. It
139        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
140        characters, are recognized by isspace() and therefore were getting set in
141        these tables, and indeed these tables seem to approximate to ISO 8859. This
142        caused a problem in UTF-8 mode when pcre_study() was used to create a list
143        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
144        which of course cannot start UTF-8 characters. I have changed the code so
145        that only real ASCII characters (less than 128) and the correct starting
146        bytes for UTF-8 encodings are set for characters greater than 127 when in
147        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
148        altogether.)
149    
150    20. Added the /T option to pcretest so as to be able to run tests with non-
151        standard character tables, thus making it possible to include the tests
152        used for 19 above in the standard set of tests.
153    
154    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
155        reference to a subpattern the other side of a comment that contains an
156        opening parenthesis caused either an internal compiling error, or a
157        reference to the wrong subpattern.
158    
159    
160    Version 8.02 19-Mar-2010
161    ------------------------
162    
163    1.  The Unicode data tables have been updated to Unicode 5.2.0.
164    
165    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
166        configured.
167    
168    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
169        original author of that file, following a query about its status.
170    
171    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
172        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
173    
174    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
175        quantifier applied to a forward-referencing subroutine call, could compile
176        incorrect code or give the error "internal error: previously-checked
177        referenced subpattern not found".
178    
179    6.  Both MS Visual Studio and Symbian OS have problems with initializing
180        variables to point to external functions. For these systems, therefore,
181        pcre_malloc etc. are now initialized to local functions that call the
182        relevant global functions.
183    
184    7.  There were two entries missing in the vectors called coptable and poptable
185        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
186        I've fixed the data, and added a kludgy way of testing at compile time that
187        the lengths are correct (equal to the number of opcodes).
188    
189    8.  Following on from 7, I added a similar kludge to check the length of the
190        eint vector in pcreposix.c.
191    
192    9.  Error texts for pcre_compile() are held as one long string to avoid too
193        much relocation at load time. To find a text, the string is searched,
194        counting zeros. There was no check for running off the end of the string,
195        which could happen if a new error number was added without updating the
196        string.
197    
198    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
199    
200    11. \K was not working if it appeared in an atomic group or in a group that
201        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
202        \K is "not well defined" if used in an assertion. PCRE now accepts it if
203        the assertion is positive, but not if it is negative.
204    
205    12. Change 11 fortuitously reduced the size of the stack frame used in the
206        "match()" function of pcre_exec.c by one pointer. Forthcoming
207        implementation of support for (*MARK) will need an extra pointer on the
208        stack; I have reserved it now, so that the stack frame size does not
209        decrease.
210    
211    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
212        item in branch that calls a recursion is a subroutine call - as in the
213        second branch in the above example - was incorrectly given the compile-
214        time error "recursive call could loop indefinitely" because pcre_compile()
215        was not correctly checking the subroutine for matching a non-empty string.
216    
217    14. The checks for overrunning compiling workspace could trigger after an
218        overrun had occurred. This is a "should never occur" error, but it can be
219        triggered by pathological patterns such as hundreds of nested parentheses.
220        The checks now trigger 100 bytes before the end of the workspace.
221    
222    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
223    
224    
225    Version 8.01 19-Jan-2010
226    ------------------------
227    
228    1.  If a pattern contained a conditional subpattern with only one branch (in
229        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
230        computed the wrong minimum data length (which is of course zero for such
231        subpatterns). This could cause incorrect "no match" results.
232    
233    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
234        the pattern is reset in the first branch, pcre_compile() failed with
235        "internal error: code overflow at offset...". This happened only when
236        the reset was to the original external option setting. (An optimization
237        abstracts leading options settings into an external setting, which was the
238        cause of this.)
239    
240    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
241        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
242        assertion pattern did not match (meaning that the assertion was true), it
243        was incorrectly treated as false if the SKIP had been reached during the
244        matching. This also applied to assertions used as conditions.
245    
246    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
247        assertion subpattern, including such a pattern used as a condition,
248        unpredictable results occurred, instead of the error return
249        PCRE_ERROR_DFA_UITEM.
250    
251    5.  The C++ GlobalReplace function was not working like Perl for the special
252        situation when an empty string is matched. It now does the fancy magic
253        stuff that is necessary.
254    
255    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
256        removed. (These were left over from very, very early versions of PCRE.)
257    
258    7.  Some cosmetic changes to the code to make life easier when compiling it
259        as part of something else:
260    
261        (a) Change DEBUG to PCRE_DEBUG.
262    
263        (b) In pcre_compile(), rename the member of the "branch_chain" structure
264            called "current" as "current_branch", to prevent a collision with the
265            Linux macro when compiled as a kernel module.
266    
267        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
268            prevent a collision with the Linux macro when compiled as a kernel
269            module.
270    
271    8.  In pcre_compile() there are some checks for integer overflows that used to
272        cast potentially large values to (double). This has been changed to that
273        when building, a check for int64_t is made, and if it is found, it is used
274        instead, thus avoiding the use of floating point arithmetic. (There is no
275        other use of FP in PCRE.) If int64_t is not found, the fallback is to
276        double.
277    
278    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
279        2005 (difference between two addresses compared to an unsigned value).
280    
281    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
282        custom one, because of the following reported problem in Windows:
283    
284          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
285              under Win32.
286          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
287              therefore missing the function definition.
288          - The compiler thus generates a "C" signature for the test function.
289          - The linker fails to find the "C" function.
290          - PCRE fails to configure if asked to do so against libbz2.
291    
292    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
293        messages were output:
294    
295          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
296          rerunning libtoolize, to keep the correct libtool macros in-tree.
297          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
298    
299        I have done both of these things.
300    
301    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
302        most of the time, it *can* run out if it is given a pattern that contains a
303        runaway infinite recursion. I updated the discussion in the pcrestack man
304        page.
305    
306    13. Now that we have gone to the x.xx style of version numbers, the minor
307        version may start with zero. Using 08 or 09 is a bad idea because users
308        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
309        interpreted as invalid octal numbers. I've updated the previous comment in
310        configure.ac, and also added a check that gives an error if 08 or 09 are
311        used.
312    
313    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
314        causing partial matching to fail when the end of the subject matched \W
315        in a UTF-8 pattern where \W was quantified with a minimum of 3.
316    
317    15. There were some discrepancies between the declarations in pcre_internal.h
318        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
319        their definitions. The declarations used "const uschar *" and the
320        definitions used USPTR. Even though USPTR is normally defined as "const
321        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
322        reported that: "This difference in casting confuses some C++ compilers, for
323        example, SunCC recognizes above declarations as different functions and
324        generates broken code for hbpcre." I have changed the declarations to use
325        USPTR.
326    
327    16. GNU libtool is named differently on some systems. The autogen.sh script now
328        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
329        (FreeBSD).
330    
331    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
332        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
333        comment: "Figure out how to create a longlong from a string: strtoll and
334        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
335        instance, but it only takes 2 args instead of 3!"
336    
337    18. A subtle bug concerned with back references has been fixed by a change of
338        specification, with a corresponding code fix. A pattern such as
339        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
340        refers, was giving matches when it shouldn't. For example, xa=xaaa would
341        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
342        same bug. Such groups have to be quantified to be useful, or contained
343        inside another quantified group. (If there's no repetition, the reference
344        can never match.) The problem arises because, having left the group and
345        moved on to the rest of the pattern, a later failure that backtracks into
346        the group uses the captured value from the final iteration of the group
347        rather than the correct earlier one. I have fixed this in PCRE by forcing
348        any group that contains a reference to itself to be an atomic group; that
349        is, there cannot be any backtracking into it once it has completed. This is
350        similar to recursive and subroutine calls.
351    
352    
353    Version 8.00 19-Oct-09
354  ----------------------  ----------------------
355    
356  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
357      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
358      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
359      error.      error.
360    
361  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
362      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
363      in a Windows environment.      in a Windows environment.
364    
365  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
366      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
367      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
368      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
369      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
370      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
371      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
372    
373  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
374      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
375      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
376      the old behaviour.      the old behaviour.
377    
378  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
379      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
380      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
381      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
382    
383  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
384      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
385    
386  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
387      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
388      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
389      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
390      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
391      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
392    
393  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
394      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
395      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
396      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
397      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
398      result.      result.
399    
400  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
401      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
402      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
403      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
404      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
405      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
406    
407  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
408      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
409      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
410      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
411      pcre_exec().  
412    11. Partial matching with pcre_exec() is now more intuitive. A partial match
413  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
414      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
415      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
416      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
417      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
418      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
419      final character ended with (*FAIL).  
   
420  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
421      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
422      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
423      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
424      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
425      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
426    
427  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
428      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
429      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
430      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
431      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
432      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
433    
434  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
435      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
436      PCRE has not been installed from source.      PCRE has not been installed from source.
437    
438  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
439      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
440      library.      library.
441    
442  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
443      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
444      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
445      these options useful.      these options useful.
446    
447  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
448      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
449      nmatch is forced to zero.      nmatch is forced to zero.
450    
451  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
452      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
453      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
454    
455  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
456      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
457      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
458      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
459      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
460      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
461      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
462      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
463    
464  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
465      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
466      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
467      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
468    
469  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
470      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
471      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
472      now given.      now given.
473    
474  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
475      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
476      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
477      compatible with Perl.      compatible with Perl.
478    
479  23. The tests have been re-organized, adding tests 11 and 12, to make it  23. The tests have been re-organized, adding tests 11 and 12, to make it
480      possible to check the Perl 5.10 features against Perl 5.10.      possible to check the Perl 5.10 features against Perl 5.10.
481    
482  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
483      pattern matches a fixed length string. PCRE did not allow this; now it      pattern matches a fixed length string. PCRE did not allow this; now it
484      does. Neither allows recursion.      does. Neither allows recursion.
485    
486  25. I finally figured out how to implement a request to provide the minimum  25. I finally figured out how to implement a request to provide the minimum
487      length of subject string that was needed in order to match a given pattern.      length of subject string that was needed in order to match a given pattern.
488      (It was back references and recursion that I had previously got hung up      (It was back references and recursion that I had previously got hung up
489      on.) This code has now been added to pcre_study(); it finds a lower bound      on.) This code has now been added to pcre_study(); it finds a lower bound
490      to the length of subject needed. It is not necessarily the greatest lower      to the length of subject needed. It is not necessarily the greatest lower
491      bound, but using it to avoid searching strings that are too short does give      bound, but using it to avoid searching strings that are too short does give
492      some useful speed-ups. The value is available to calling programs via      some useful speed-ups. The value is available to calling programs via
493      pcre_fullinfo().      pcre_fullinfo().
494    
495  26. While implementing 25, I discovered to my embarrassment that pcretest had  26. While implementing 25, I discovered to my embarrassment that pcretest had
496      not been passing the result of pcre_study() to pcre_dfa_exec(), so the      not been passing the result of pcre_study() to pcre_dfa_exec(), so the
497      study optimizations had never been tested with that matching function.      study optimizations had never been tested with that matching function.
498      Oops. What is worse, even when it was passed study data, there was a bug in      Oops. What is worse, even when it was passed study data, there was a bug in
499      pcre_dfa_exec() that meant it never actually used it. Double oops. There      pcre_dfa_exec() that meant it never actually used it. Double oops. There
500      were also very few tests of studied patterns with pcre_dfa_exec().      were also very few tests of studied patterns with pcre_dfa_exec().
501    
502    27. If (?| is used to create subpatterns with duplicate numbers, they are now
503        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
504        on the other side of the coin, they are no longer allowed to have different
505        names, because these cannot be distinguished in PCRE, and this has caused
506        confusion. (This is a difference from Perl.)
507    
508    28. When duplicate subpattern names are present (necessarily with different
509        numbers, as required by 27 above), and a test is made by name in a
510        conditional pattern, either for a subpattern having been matched, or for
511        recursion in such a pattern, all the associated numbered subpatterns are
512        tested, and the overall condition is true if the condition is true for any
513        one of them. This is the way Perl works, and is also more like the way
514        testing by number works.
515    
516    
517  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
518  ---------------------  ---------------------

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