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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 217 by ph10, Wed Aug 15 15:21:04 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 09-Aug-07
5    ---------------------
6    
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
50    
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
55    
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
67    
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
72    
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
79    
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
86    
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
90    
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93    
94    14. Optimized (?!) to (*FAIL).
95    
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
101    
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
105    
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
108    
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
111    
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
116    
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
119    
120    
121    Version 7.2 19-Jun-07
122    ---------------------
123    
124     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
125        which is apparently normally available under Windows.
126    
127     2. Re-jig the pcregrep tests with different newline settings in an attempt
128        to make them independent of the local environment's newline setting.
129    
130     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
131    
132     4. Some of the "internals" tests were previously cut out when the link size
133        was not 2, because the output contained actual offsets. The recent new
134        "Z" feature of pcretest means that these can be cut out, making the tests
135        usable with all link sizes.
136    
137     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
138        stack recursion. This gives a massive performance boost under BSD, but just
139        a small improvement under Linux. However, it saves one field in the frame
140        in all cases.
141    
142     6. Added more features from the forthcoming Perl 5.10:
143    
144        (a) (?-n) (where n is a string of digits) is a relative subroutine or
145            recursion call. It refers to the nth most recently opened parentheses.
146    
147        (b) (?+n) is also a relative subroutine call; it refers to the nth next
148            to be opened parentheses.
149    
150        (c) Conditions that refer to capturing parentheses can be specified
151            relatively, for example, (?(-2)... or (?(+3)...
152    
153        (d) \K resets the start of the current match so that everything before
154            is not part of it.
155    
156        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
157    
158        (f) \g{name} is another synonym - part of Perl 5.10's unification of
159            reference syntax.
160    
161        (g) (?| introduces a group in which the numbering of parentheses in each
162            alternative starts with the same number.
163    
164        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
165    
166     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
167        PCRE_INFO_JCHANGED.
168    
169     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
170        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
171        for detecting groups that can match an empty string.
172    
173     9. A pattern with a very large number of alternatives (more than several
174        hundred) was running out of internal workspace during the pre-compile
175        phase, where pcre_compile() figures out how much memory will be needed. A
176        bit of new cunning has reduced the workspace needed for groups with
177        alternatives. The 1000-alternative test pattern now uses 12 bytes of
178        workspace instead of running out of the 4096 that are available.
179    
180    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
181    
182    11. Applied patch from Google to remove an optimization that didn't quite work.
183        The report of the bug said:
184    
185          pcrecpp::RE("a*").FullMatch("aaa") matches, while
186          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
187          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
188    
189    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
190        it matched the wrong number of bytes.
191    
192    
193    Version 7.1 24-Apr-07
194    ---------------------
195    
196     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
197        that is more "standard", making use of automake and other Autotools. There
198        is some re-arrangement of the files and adjustment of comments consequent
199        on this.
200    
201     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
202        for recursive directory scanning broke on some systems because the files
203        are not scanned in any specific order and on different systems the order
204        was different. A call to "sort" has been inserted into RunGrepTest for the
205        approprate test as a short-term fix. In the longer term there may be an
206        alternative.
207    
208     3. I had an email from Eric Raymond about problems translating some of PCRE's
209        man pages to HTML (despite the fact that I distribute HTML pages, some
210        people do their own conversions for various reasons). The problems
211        concerned the use of low-level troff macros .br and .in. I have therefore
212        removed all such uses from the man pages (some were redundant, some could
213        be replaced by .nf/.fi pairs). The 132html script that I use to generate
214        HTML has been updated to handle .nf/.fi and to complain if it encounters
215        .br or .in.
216    
217     4. Updated comments in configure.ac that get placed in config.h.in and also
218        arranged for config.h to be included in the distribution, with the name
219        config.h.generic, for the benefit of those who have to compile without
220        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
221    
222     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
223        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
224        makevp.bat for the current PCRE, using the additional files
225        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
226    
227     6. A Windows user reported a minor discrepancy with test 2, which turned out
228        to be caused by a trailing space on an input line that had got lost in his
229        copy. The trailing space was an accident, so I've just removed it.
230    
231     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
232        that is needed.
233    
234     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
235        as "const" (a) because they are and (b) because it helps the PHP
236        maintainers who have recently made a script to detect big data structures
237        in the php code that should be moved to the .rodata section. I remembered
238        to update Builducptable as well, so it won't revert if ucptable.h is ever
239        re-created.
240    
241     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
242        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
243        order to be able to cut out the UTF-8 tables in the latter when UTF-8
244        support is not required. This saves 1.5-2K of code, which is important in
245        some applications.
246    
247        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
248        so as not to refer to the tables, even though these functions will never be
249        called when UTF-8 support is disabled. Otherwise there are problems with a
250        shared library.
251    
252    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
253    
254        (a) It was defining its arguments as char * instead of void *.
255    
256        (b) It was assuming that all moves were upwards in memory; this was true
257            a long time ago when I wrote it, but is no longer the case.
258    
259        The emulated memove() is provided for those environments that have neither
260        memmove() nor bcopy(). I didn't think anyone used it these days, but that
261        is clearly not the case, as these two bugs were recently reported.
262    
263    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
264        and Detrail to create the HTML documentation, the .txt form of the man
265        pages, and it removes trailing spaces from listed files. It also creates
266        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
267        case, it wraps all the #defines with #ifndefs. This script should be run
268        before "make dist".
269    
270    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
271        with Unicode property support.
272    
273        (a) For a maximizing quantifier, if the two different cases of the
274            character were of different lengths in their UTF-8 codings (there are
275            some cases like this - I found 11), and the matching function had to
276            back up over a mixture of the two cases, it incorrectly assumed they
277            were both the same length.
278    
279        (b) When PCRE was configured to use the heap rather than the stack for
280            recursion during matching, it was not correctly preserving the data for
281            the other case of a UTF-8 character when checking ahead for a match
282            while processing a minimizing repeat. If the check also involved
283            matching a wide character, but failed, corruption could cause an
284            erroneous result when trying to check for a repeat of the original
285            character.
286    
287    13. Some tidying changes to the testing mechanism:
288    
289        (a) The RunTest script now detects the internal link size and whether there
290            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
291            values substituted by "configure". (The RunGrepTest script already did
292            this for UTF-8.) The configure.ac script no longer substitutes the
293            relevant variables.
294    
295        (b) The debugging options /B and /D in pcretest show the compiled bytecode
296            with length and offset values. This means that the output is different
297            for different internal link sizes. Test 2 is skipped for link sizes
298            other than 2 because of this, bypassing the problem. Unfortunately,
299            there was also a test in test 3 (the locale tests) that used /B and
300            failed for link sizes other than 2. Rather than cut the whole test out,
301            I have added a new /Z option to pcretest that replaces the length and
302            offset values with spaces. This is now used to make test 3 independent
303            of link size. (Test 2 will be tidied up later.)
304    
305    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
306        segmentation fault instead of returning the appropriate error message.
307    
308    15. In multiline mode when the newline sequence was set to "any", the pattern
309        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
310        This doesn't seem right; it now treats the CRLF combination as the line
311        ending, and so does not match in that case. It's only a pattern such as ^$
312        that would hit this one: something like ^ABC$ would have failed after \r
313        and then tried again after \r\n.
314    
315    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
316        in an attempt to make files that differ only in their line terminators
317        compare equal. This works on Linux.
318    
319    17. Under certain error circumstances pcregrep might try to free random memory
320        as it exited. This is now fixed, thanks to valgrind.
321    
322    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
323        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
324        was because its rules for how to advance for /g after matching an empty
325        string at the end of a line did not allow for this case. They now check for
326        it specially.
327    
328    20. pcretest is supposed to handle patterns and data of any length, by
329        extending its buffers when necessary. It was getting this wrong when the
330        buffer for a data line had to be extended.
331    
332    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
333        CRLF as a newline sequence.
334    
335    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
336        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
337        I have nevertheless tidied it up.
338    
339    23. Added some casts to kill warnings from HP-UX ia64 compiler.
340    
341    24. Added a man page for pcre-config.
342    
343    
344    Version 7.0 19-Dec-06
345    ---------------------
346    
347     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
348        moving to gcc 4.1.1.
349    
350     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
351        sys/time.h, which is documented as needed for this function. It doesn't
352        seem to matter on Linux, but it showed up on some releases of OS X.
353    
354     3. It seems that there are systems where bytes whose values are greater than
355        127 match isprint() in the "C" locale. The "C" locale should be the
356        default when a C program starts up. In most systems, only ASCII printing
357        characters match isprint(). This difference caused the output from pcretest
358        to vary, making some of the tests fail. I have changed pcretest so that:
359    
360        (a) When it is outputting text in the compiled version of a pattern, bytes
361            other than 32-126 are always shown as hex escapes.
362    
363        (b) When it is outputting text that is a matched part of a subject string,
364            it does the same, unless a different locale has been set for the match
365            (using the /L modifier). In this case, it uses isprint() to decide.
366    
367     4. Fixed a major bug that caused incorrect computation of the amount of memory
368        required for a compiled pattern when options that changed within the
369        pattern affected the logic of the preliminary scan that determines the
370        length. The relevant options are -x, and -i in UTF-8 mode. The result was
371        that the computed length was too small. The symptoms of this bug were
372        either the PCRE error "internal error: code overflow" from pcre_compile(),
373        or a glibc crash with a message such as "pcretest: free(): invalid next
374        size (fast)". Examples of patterns that provoked this bug (shown in
375        pcretest format) are:
376    
377          /(?-x: )/x
378          /(?x)(?-x: \s*#\s*)/
379          /((?i)[\x{c0}])/8
380          /(?i:[\x{c0}])/8
381    
382        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
383        is now done differently.
384    
385     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
386        wrapper classes; (b) implement a new function in the C++ scanner that is
387        more efficient than the old way of doing things because it avoids levels of
388        recursion in the regex matching; (c) add a paragraph to the documentation
389        for the FullMatch() function.
390    
391     6. The escape sequence \n was being treated as whatever was defined as
392        "newline". Not only was this contrary to the documentation, which states
393        that \n is character 10 (hex 0A), but it also went horribly wrong when
394        "newline" was defined as CRLF. This has been fixed.
395    
396     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
397        was being set to -1 for the "end of line" case (supposedly a value that no
398        character can have). Though this value is never used (the check for end of
399        line is "zero bytes in current character"), it caused compiler complaints.
400        I've changed it to 0xffffffff.
401    
402     8. In pcre_version.c, the version string was being built by a sequence of
403        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
404        string (as it is for production releases) called a macro with an empty
405        argument. The C standard says the result of this is undefined. The gcc
406        compiler treats it as an empty string (which was what was wanted) but it is
407        reported that Visual C gives an error. The source has been hacked around to
408        avoid this problem.
409    
410     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
411        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
412        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
413        of them did).
414    
415    10. Originally, pcretest opened its input and output without "b"; then I was
416        told that "b" was needed in some environments, so it was added for release
417        5.0 to both the input and output. (It makes no difference on Unix-like
418        systems.) Later I was told that it is wrong for the input on Windows. I've
419        now abstracted the modes into two macros, to make it easier to fiddle with
420        them, and removed "b" from the input mode under Windows.
421    
422    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
423    
424    12. Added -help and --help to pcretest as an official way of being reminded
425        of the options.
426    
427    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
428        and pcrecpp.cc because they annoy compilers at high warning levels.
429    
430    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
431    
432    15. Fixed an occurrence of == in configure.ac that should have been = (shell
433        scripts are not C programs :-) and which was not noticed because it works
434        on Linux.
435    
436    16. pcretest is supposed to handle any length of pattern and data line (as one
437        line or as a continued sequence of lines) by extending its input buffer if
438        necessary. This feature was broken for very long pattern lines, leading to
439        a string of junk being passed to pcre_compile() if the pattern was longer
440        than about 50K.
441    
442    17. I have done a major re-factoring of the way pcre_compile() computes the
443        amount of memory needed for a compiled pattern. Previously, there was code
444        that made a preliminary scan of the pattern in order to do this. That was
445        OK when PCRE was new, but as the facilities have expanded, it has become
446        harder and harder to keep it in step with the real compile phase, and there
447        have been a number of bugs (see for example, 4 above). I have now found a
448        cunning way of running the real compile function in a "fake" mode that
449        enables it to compute how much memory it would need, while actually only
450        ever using a few hundred bytes of working memory and without too many
451        tests of the mode. This should make future maintenance and development
452        easier. A side effect of this work is that the limit of 200 on the nesting
453        depth of parentheses has been removed (though this was never a serious
454        limitation, I suspect). However, there is a downside: pcre_compile() now
455        runs more slowly than before (30% or more, depending on the pattern). I
456        hope this isn't a big issue. There is no effect on runtime performance.
457    
458    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
459        newline (only possible for the last line of a file) and it was a
460        pattern that set a locale (followed by /Lsomething), pcretest crashed.
461    
462    19. Added additional timing features to pcretest. (1) The -tm option now times
463        matching only, not compiling. (2) Both -t and -tm can be followed, as a
464        separate command line item, by a number that specifies the number of
465        repeats to use when timing. The default is 50000; this gives better
466        precision, but takes uncomfortably long for very large patterns.
467    
468    20. Extended pcre_study() to be more clever in cases where a branch of a
469        subpattern has no definite first character. For example, (a*|b*)[cd] would
470        previously give no result from pcre_study(). Now it recognizes that the
471        first character must be a, b, c, or d.
472    
473    21. There was an incorrect error "recursive call could loop indefinitely" if
474        a subpattern (or the entire pattern) that was being tested for matching an
475        empty string contained only one non-empty item after a nested subpattern.
476        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
477        incorrectly, because the \d was being skipped in the check.
478    
479    22. The pcretest program now has a new pattern option /B and a command line
480        option -b, which is equivalent to adding /B to every pattern. This causes
481        it to show the compiled bytecode, without the additional information that
482        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
483        is the same as /B/I).
484    
485    23. A new optimization is now able automatically to treat some sequences such
486        as a*b as a*+b. More specifically, if something simple (such as a character
487        or a simple class like \d) has an unlimited quantifier, and is followed by
488        something that cannot possibly match the quantified thing, the quantifier
489        is automatically "possessified".
490    
491    24. A recursive reference to a subpattern whose number was greater than 39
492        went wrong under certain circumstances in UTF-8 mode. This bug could also
493        have affected the operation of pcre_study().
494    
495    25. Realized that a little bit of performance could be had by replacing
496        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
497    
498    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
499    
500    27. Possessive quantifiers such as a++ were previously implemented by turning
501        them into atomic groups such as ($>a+). Now they have their own opcodes,
502        which improves performance. This includes the automatically created ones
503        from 23 above.
504    
505    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
506        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
507        the first matched character to be a colon. This applied both to named and
508        numbered groups.
509    
510    29. The ucpinternal.h header file was missing its idempotency #ifdef.
511    
512    30. I was sent a "project" file called libpcre.a.dev which I understand makes
513        building PCRE on Windows easier, so I have included it in the distribution.
514    
515    31. There is now a check in pcretest against a ridiculously large number being
516        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
517        loop, the loop is abandoned.
518    
519    32. Forward references to subpatterns in conditions such as (?(2)...) where
520        subpattern 2 is defined later cause pcre_compile() to search forwards in
521        the pattern for the relevant set of parentheses. This search went wrong
522        when there were unescaped parentheses in a character class, parentheses
523        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
524    
525    33. "Subroutine" calls and backreferences were previously restricted to
526        referencing subpatterns earlier in the regex. This restriction has now
527        been removed.
528    
529    34. Added a number of extra features that are going to be in Perl 5.10. On the
530        whole, these are just syntactic alternatives for features that PCRE had
531        previously implemented using the Python syntax or my own invention. The
532        other formats are all retained for compatibility.
533    
534        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
535            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
536            also .NET compatible.
537    
538        (b) A recursion or subroutine call to a named group can now be defined as
539            (?&name) as well as (?P>name).
540    
541        (c) A backreference to a named group can now be defined as \k<name> or
542            \k'name' as well as (?P=name). The new forms, as well as being in Perl
543            5.10, are also .NET compatible.
544    
545        (d) A conditional reference to a named group can now use the syntax
546            (?(<name>) or (?('name') as well as (?(name).
547    
548        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
549            groups (named and numbered) that are never evaluated inline, but can be
550            called as "subroutines" from elsewhere. In effect, the DEFINE condition
551            is always false. There may be only one alternative in such a group.
552    
553        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
554            as the simple (?(R). The condition is true only if the most recent
555            recursion is that of the given number or name. It does not search out
556            through the entire recursion stack.
557    
558        (g) The escape \gN or \g{N} has been added, where N is a positive or
559            negative number, specifying an absolute or relative reference.
560    
561    35. Tidied to get rid of some further signed/unsigned compiler warnings and
562        some "unreachable code" warnings.
563    
564    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
565        things, this adds five new scripts.
566    
567    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
568        There were also incompatibilities regarding the handling of \Q..\E inside
569        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
570        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
571    
572    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
573        matches an empty string, and forcibly breaks the loop. There were bugs in
574        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
575        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
576        separate and independent bugs (that affected different cases) have been
577        fixed.
578    
579    39. Refactored the code to abolish the use of different opcodes for small
580        capturing bracket numbers. This is a tidy that I avoided doing when I
581        removed the limit on the number of capturing brackets for 3.5 back in 2001.
582        The new approach is not only tidier, it makes it possible to reduce the
583        memory needed to fix the previous bug (38).
584    
585    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
586        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
587        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
588        mode.
589    
590    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
591        report.
592    
593    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
594        copy construction and assignment in the C++ wrapper.
595    
596    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
597        couple of bugs that could have given wrong results in the "--newline=crlf"
598        case.
599    
600    44. Added a number of casts and did some reorganization of signed/unsigned int
601        variables following suggestions from Dair Grant. Also renamed the variable
602        "this" as "item" because it is a C++ keyword.
603    
604    45. Arranged for dftables to add
605    
606          #include "pcre_internal.h"
607    
608        to pcre_chartables.c because without it, gcc 4.x may remove the array
609        definition from the final binary if PCRE is built into a static library and
610        dead code stripping is activated.
611    
612    46. For an unanchored pattern, if a match attempt fails at the start of a
613        newline sequence, and the newline setting is CRLF or ANY, and the next two
614        characters are CRLF, advance by two characters instead of one.
615    
616    
617    Version 6.7 04-Jul-06
618    ---------------------
619    
620     1. In order to handle tests when input lines are enormously long, pcretest has
621        been re-factored so that it automatically extends its buffers when
622        necessary. The code is crude, but this _is_ just a test program. The
623        default size has been increased from 32K to 50K.
624    
625     2. The code in pcre_study() was using the value of the re argument before
626        testing it for NULL. (Of course, in any sensible call of the function, it
627        won't be NULL.)
628    
629     3. The memmove() emulation function in pcre_internal.h, which is used on
630        systems that lack both memmove() and bcopy() - that is, hardly ever -
631        was missing a "static" storage class specifier.
632    
633     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
634        containing an extended class (one that cannot be represented by a bitmap
635        because it contains high-valued characters or Unicode property items, e.g.
636        [\pZ]). Almost always one would set UTF-8 mode when processing such a
637        pattern, but PCRE should not loop if you do not (it no longer does).
638        [Detail: two cases were found: (a) a repeated subpattern containing an
639        extended class; (b) a recursive reference to a subpattern that followed a
640        previous extended class. It wasn't skipping over the extended class
641        correctly when UTF-8 mode was not set.]
642    
643     5. A negated single-character class was not being recognized as fixed-length
644        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
645        compile error "lookbehind assertion is not fixed length".
646    
647     6. The RunPerlTest auxiliary script was showing an unexpected difference
648        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
649        write a Perl script that can interpret lines of an input file either as
650        byte characters or as UTF-8, which is what "perltest" was being required to
651        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
652        can't do is switch easily at run time between having the "use utf8;" pragma
653        or not. In the end, I fudged it by using the RunPerlTest script to insert
654        "use utf8;" explicitly for the UTF-8 tests.
655    
656     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
657        the end of the subject string, contrary to the documentation and to what
658        Perl does. This was true of both matching functions. Now it matches only at
659        the start of the subject and immediately after *internal* newlines.
660    
661     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
662        a pointer to an int instead of a pointer to an unsigned long int. This
663        caused problems on 64-bit systems.
664    
665     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
666        instance of the 'standard' template library not being so standard".
667    
668    10. There was no check on the number of named subpatterns nor the maximum
669        length of a subpattern name. The product of these values is used to compute
670        the size of the memory block for a compiled pattern. By supplying a very
671        long subpattern name and a large number of named subpatterns, the size
672        computation could be caused to overflow. This is now prevented by limiting
673        the length of names to 32 characters, and the number of named subpatterns
674        to 10,000.
675    
676    11. Subpatterns that are repeated with specific counts have to be replicated in
677        the compiled pattern. The size of memory for this was computed from the
678        length of the subpattern and the repeat count. The latter is limited to
679        65535, but there was no limit on the former, meaning that integer overflow
680        could in principle occur. The compiled length of a repeated subpattern is
681        now limited to 30,000 bytes in order to prevent this.
682    
683    12. Added the optional facility to have named substrings with the same name.
684    
685    13. Added the ability to use a named substring as a condition, using the
686        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
687        are numbers (not recommended). Forward references are permitted.
688    
689    14. Added forward references in named backreferences (if you see what I mean).
690    
691    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
692        pattern could run off the end of the subject. For example, the pattern
693        "(?s)(.{1,5})"8 did this with the subject "ab".
694    
695    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
696        PCRE_CASELESS was set when matching characters that were quantified with ?
697        or *.
698    
699    17. A character class other than a single negated character that had a minimum
700        but no maximum quantifier - for example [ab]{6,} - was not handled
701        correctly by pce_dfa_exec(). It would match only one character.
702    
703    18. A valid (though odd) pattern that looked like a POSIX character
704        class but used an invalid character after [ (for example [[,abc,]]) caused
705        pcre_compile() to give the error "Failed: internal error: code overflow" or
706        in some cases to crash with a glibc free() error. This could even happen if
707        the pattern terminated after [[ but there just happened to be a sequence of
708        letters, a binary zero, and a closing ] in the memory that followed.
709    
710    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
711        over the years. Originally (before any Unicode support), just the bottom 8
712        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
713        output from "man perlunicode" includes this:
714    
715          The regular expression compiler produces polymorphic opcodes.  That
716          is, the pattern adapts to the data and automatically switches to
717          the Unicode character scheme when presented with Unicode data--or
718          instead uses a traditional byte scheme when presented with byte
719          data.
720    
721        Sadly, a wide octal escape does not cause a switch, and in a string with
722        no other multibyte characters, these octal escapes are treated as before.
723        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
724        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
725        Unicode string.
726    
727        I have not perpetrated such confusion in PCRE. Up till now, it took just
728        the bottom 8 bits, as in old Perl. I have now made octal escapes with
729        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
730        translate to the appropriate multibyte character.
731    
732    29. Applied some refactoring to reduce the number of warnings from Microsoft
733        and Borland compilers. This has included removing the fudge introduced
734        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
735        a warning about an unused variable.
736    
737    21. PCRE has not included VT (character 0x0b) in the set of whitespace
738        characters since release 4.0, because Perl (from release 5.004) does not.
739        [Or at least, is documented not to: some releases seem to be in conflict
740        with the documentation.] However, when a pattern was studied with
741        pcre_study() and all its branches started with \s, PCRE still included VT
742        as a possible starting character. Of course, this did no harm; it just
743        caused an unnecessary match attempt.
744    
745    22. Removed a now-redundant internal flag bit that recorded the fact that case
746        dependency changed within the pattern. This was once needed for "required
747        byte" processing, but is no longer used. This recovers a now-scarce options
748        bit. Also moved the least significant internal flag bit to the most-
749        significant bit of the word, which was not previously used (hangover from
750        the days when it was an int rather than a uint) to free up another bit for
751        the future.
752    
753    23. Added support for CRLF line endings as well as CR and LF. As well as the
754        default being selectable at build time, it can now be changed at runtime
755        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
756        specify that it is scanning data with non-default line endings.
757    
758    24. Changed the definition of CXXLINK to make it agree with the definition of
759        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
760    
761    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
762        recursions. This makes a big different to stack usage for some patterns.
763    
764    26. If a subpattern containing a named recursion or subroutine reference such
765        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
766        the space required for the compiled pattern went wrong and gave too small a
767        value. Depending on the environment, this could lead to "Failed: internal
768        error: code overflow at offset 49" or "glibc detected double free or
769        corruption" errors.
770    
771    27. Applied patches from Google (a) to support the new newline modes and (b) to
772        advance over multibyte UTF-8 characters in GlobalReplace.
773    
774    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
775        difference for some implementation of PCRE in some Windows version.
776    
777    29. Added some extra testing facilities to pcretest:
778    
779        \q<number>   in a data line sets the "match limit" value
780        \Q<number>   in a data line sets the "match recursion limt" value
781        -S <number>  sets the stack size, where <number> is in megabytes
782    
783        The -S option isn't available for Windows.
784    
785    
786    Version 6.6 06-Feb-06
787    ---------------------
788    
789     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
790        in pcreposix.h. I have copied the definition from pcre.h.
791    
792     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
793        because pcre.h is no longer a built file.
794    
795     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
796        not normally included in the compiled code.
797    
798    
799    Version 6.5 01-Feb-06
800    ---------------------
801    
802     1. When using the partial match feature with pcre_dfa_exec(), it was not
803        anchoring the second and subsequent partial matches at the new starting
804        point. This could lead to incorrect results. For example, with the pattern
805        /1234/, partially matching against "123" and then "a4" gave a match.
806    
807     2. Changes to pcregrep:
808    
809        (a) All non-match returns from pcre_exec() were being treated as failures
810            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
811            error message is output. Some extra information is given for the
812            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
813            probably the only errors that are likely to be caused by users (by
814            specifying a regex that has nested indefinite repeats, for instance).
815            If there are more than 20 of these errors, pcregrep is abandoned.
816    
817        (b) A binary zero was treated as data while matching, but terminated the
818            output line if it was written out. This has been fixed: binary zeroes
819            are now no different to any other data bytes.
820    
821        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
822            used to set a locale for matching. The --locale=xxxx long option has
823            been added (no short equivalent) to specify a locale explicitly on the
824            pcregrep command, overriding the environment variables.
825    
826        (d) When -B was used with -n, some line numbers in the output were one less
827            than they should have been.
828    
829        (e) Added the -o (--only-matching) option.
830    
831        (f) If -A or -C was used with -c (count only), some lines of context were
832            accidentally printed for the final match.
833    
834        (g) Added the -H (--with-filename) option.
835    
836        (h) The combination of options -rh failed to suppress file names for files
837            that were found from directory arguments.
838    
839        (i) Added the -D (--devices) and -d (--directories) options.
840    
841        (j) Added the -F (--fixed-strings) option.
842    
843        (k) Allow "-" to be used as a file name for -f as well as for a data file.
844    
845        (l) Added the --colo(u)r option.
846    
847        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
848            is not present by default.
849    
850     3. A nasty bug was discovered in the handling of recursive patterns, that is,
851        items such as (?R) or (?1), when the recursion could match a number of
852        alternatives. If it matched one of the alternatives, but subsequently,
853        outside the recursion, there was a failure, the code tried to back up into
854        the recursion. However, because of the way PCRE is implemented, this is not
855        possible, and the result was an incorrect result from the match.
856    
857        In order to prevent this happening, the specification of recursion has
858        been changed so that all such subpatterns are automatically treated as
859        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
860    
861     4. I had overlooked the fact that, in some locales, there are characters for
862        which isalpha() is true but neither isupper() nor islower() are true. In
863        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
864        and ordfeminine) are like this. This affected the treatment of \w and \W
865        when they appeared in character classes, but not when they appeared outside
866        a character class. The bit map for "word" characters is now created
867        separately from the results of isalnum() instead of just taking it from the
868        upper, lower, and digit maps. (Plus the underscore character, of course.)
869    
870     5. The above bug also affected the handling of POSIX character classes such as
871        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
872        permanent tables. Instead, the bit maps for such a class were previously
873        created as the appropriate unions of the upper, lower, and digit bitmaps.
874        Now they are created by subtraction from the [[:word:]] class, which has
875        its own bitmap.
876    
877     6. The [[:blank:]] character class matches horizontal, but not vertical space.
878        It is created by subtracting the vertical space characters (\x09, \x0a,
879        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
880        subtraction was done in the overall bitmap for a character class, meaning
881        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
882        be recognized. This bug has been fixed.
883    
884     7. Patches from the folks at Google:
885    
886          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
887          real life, but is still worth protecting against".
888    
889          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
890          regular expressions".
891    
892          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
893          have it.
894    
895          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
896          "configure" and the latter not, in order to fix a problem somebody had
897          with compiling the Arg class on HP-UX.
898    
899          (e) Improve the error-handling of the C++ wrapper a little bit.
900    
901          (f) New tests for checking recursion limiting.
902    
903     8. The pcre_memmove() function, which is used only if the environment does not
904        have a standard memmove() function (and is therefore rarely compiled),
905        contained two bugs: (a) use of int instead of size_t, and (b) it was not
906        returning a result (though PCRE never actually uses the result).
907    
908     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
909        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
910        returned instead of calling malloc() with an overflowing number that would
911        most likely cause subsequent chaos.
912    
913    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
914    
915    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
916        with this option is matched, the nmatch and pmatch options of regexec() are
917        ignored.
918    
919    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
920        provided in case anyone wants to the the POSIX interface with UTF-8
921        strings.
922    
923    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
924        C++ linking (needed for some HP-UX environments).
925    
926    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
927        (unused parameter) and in the pcre_printint() function (omitted "default"
928        switch label when the default is to do nothing).
929    
930    15. Added some code to make it possible, when PCRE is compiled as a C++
931        library, to replace subject pointers for pcre_exec() with a smart pointer
932        class, thus making it possible to process discontinuous strings.
933    
934    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
935        much the same function. They were added by different people who were trying
936        to make PCRE easy to compile on non-Unix systems. It has been suggested
937        that PCRE_EXPORT be abolished now that there is more automatic apparatus
938        for compiling on Windows systems. I have therefore replaced it with
939        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
940        defaults to "extern" for C or "extern C" for C++, which works fine on
941        Unix-like systems. It is now possible to override the value of PCRE_DATA_
942        SCOPE with something explicit in config.h. In addition:
943    
944        (a) pcreposix.h still had just "extern" instead of either of these macros;
945            I have replaced it with PCRE_DATA_SCOPE.
946    
947        (b) Functions such as _pcre_xclass(), which are internal to the library,
948            but external in the C sense, all had PCRE_EXPORT in their definitions.
949            This is apparently wrong for the Windows case, so I have removed it.
950            (It makes no difference on Unix-like systems.)
951    
952    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
953        of recursive calls to match(). This is different to MATCH_LIMIT because
954        that limits the total number of calls to match(), not all of which increase
955        the depth of recursion. Limiting the recursion depth limits the amount of
956        stack (or heap if NO_RECURSE is set) that is used. The default can be set
957        when PCRE is compiled, and changed at run time. A patch from Google adds
958        this functionality to the C++ interface.
959    
960    18. Changes to the handling of Unicode character properties:
961    
962        (a) Updated the table to Unicode 4.1.0.
963    
964        (b) Recognize characters that are not in the table as "Cn" (undefined).
965    
966        (c) I revised the way the table is implemented to a much improved format
967            which includes recognition of ranges. It now supports the ranges that
968            are defined in UnicodeData.txt, and it also amalgamates other
969            characters into ranges. This has reduced the number of entries in the
970            table from around 16,000 to around 3,000, thus reducing its size
971            considerably. I realized I did not need to use a tree structure after
972            all - a binary chop search is just as efficient. Having reduced the
973            number of entries, I extended their size from 6 bytes to 8 bytes to
974            allow for more data.
975    
976        (d) Added support for Unicode script names via properties such as \p{Han}.
977    
978    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
979        matching that character.
980    
981    20. When matching a repeated Unicode property with a minimum greater than zero,
982        (for example \pL{2,}), PCRE could look past the end of the subject if it
983        reached it while seeking the minimum number of characters. This could
984        happen only if some of the characters were more than one byte long, because
985        there is a check for at least the minimum number of bytes.
986    
987    21. Refactored the implementation of \p and \P so as to be more general, to
988        allow for more different types of property in future. This has changed the
989        compiled form incompatibly. Anybody with saved compiled patterns that use
990        \p or \P will have to recompile them.
991    
992    22. Added "Any" and "L&" to the supported property types.
993    
994    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
995        but give a compile time error if the value is greater than 0xff.
996    
997    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
998        accidentally not being installed or uninstalled.
999    
1000    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1001        made were to insert the current release number. This seemed silly, because
1002        it made things harder for people building PCRE on systems that don't run
1003        "configure". I have turned pcre.h into a distributed file, no longer built
1004        by "configure", with the version identification directly included. There is
1005        no longer a pcre.h.in file.
1006    
1007        However, this change necessitated a change to the pcre-config script as
1008        well. It is built from pcre-config.in, and one of the substitutions was the
1009        release number. I have updated configure.ac so that ./configure now finds
1010        the release number by grepping pcre.h.
1011    
1012    26. Added the ability to run the tests under valgrind.
1013    
1014    
1015    Version 6.4 05-Sep-05
1016    ---------------------
1017    
1018     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1019        "--" to be printed when multiple files were scanned, even when none of the
1020        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1021        consider it to be a bug, and have restored the previous behaviour.
1022    
1023     2. A couple of code tidies to get rid of compiler warnings.
1024    
1025     3. The pcretest program used to cheat by referring to symbols in the library
1026        whose names begin with _pcre_. These are internal symbols that are not
1027        really supposed to be visible externally, and in some environments it is
1028        possible to suppress them. The cheating is now confined to including
1029        certain files from the library's source, which is a bit cleaner.
1030    
1031     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1032        file's purpose clearer.
1033    
1034     5. Reorganized pcre_ucp_findchar().
1035    
1036    
1037    Version 6.3 15-Aug-05
1038    ---------------------
1039    
1040     1. The file libpcre.pc.in did not have general read permission in the tarball.
1041    
1042     2. There were some problems when building without C++ support:
1043    
1044        (a) If C++ support was not built, "make install" and "make test" still
1045            tried to test it.
1046    
1047        (b) There were problems when the value of CXX was explicitly set. Some
1048            changes have been made to try to fix these, and ...
1049    
1050        (c) --disable-cpp can now be used to explicitly disable C++ support.
1051    
1052        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1053            backslash in a target when C++ was disabled. This confuses some
1054            versions of "make", apparently. Using an intermediate variable solves
1055            this. (Same for CPP_LOBJ.)
1056    
1057     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1058        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1059        necessary on certain architectures.
1060    
1061     4. Added a setting of -export-symbols-regex to the link command to remove
1062        those symbols that are exported in the C sense, but actually are local
1063        within the library, and not documented. Their names all begin with
1064        "_pcre_". This is not a perfect job, because (a) we have to except some
1065        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1066        available (and never for static libraries). I have made a note to try to
1067        find a way round (a) in the future.
1068    
1069    
1070    Version 6.2 01-Aug-05
1071    ---------------------
1072    
1073     1. There was no test for integer overflow of quantifier values. A construction
1074        such as {1111111111111111} would give undefined results. What is worse, if
1075        a minimum quantifier for a parenthesized subpattern overflowed and became
1076        negative, the calculation of the memory size went wrong. This could have
1077        led to memory overwriting.
1078    
1079     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1080    
1081     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1082        operating environments where this matters.
1083    
1084     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1085        PCRE options from within the C++ wrapper.
1086    
1087     5. Named capturing subpatterns were not being correctly counted when a pattern
1088        was compiled. This caused two problems: (a) If there were more than 100
1089        such subpatterns, the calculation of the memory needed for the whole
1090        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1091        back references of the form \12, where the number was greater than 9, were
1092        not recognized as back references, even though there were sufficient
1093        previous subpatterns.
1094    
1095     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1096        versions of gcc, e.g. 2.95.4.
1097    
1098    
1099  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1100  ---------------------  ---------------------
1101    

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