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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 4.00 17-Feb-03
5    ----------------------
6    
7    1. If a comment in an extended regex that started immediately after a meta-item
8    extended to the end of string, PCRE compiled incorrect data. This could lead to
9    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
10    
11    2. Moved to autoconf 2.53 and libtool 1.4.2.
12    
13    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
14    the special perltest8 script is no longer needed - all the tests can be run
15    from a single perltest script.
16    
17    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
18    by \s. It has now been removed in PCRE. This means it isn't recognized as
19    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
20    class [:space:] *does* include VT, thereby creating a mess.
21    
22    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
23    space and tab.
24    
25    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
26    its new features into the main test script, reducing the number of scripts.
27    
28    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
29    were backward compatible, and made the (?i) apply to the whole pattern, as if
30    /i were given. Now it behaves more logically, and applies the option setting
31    only to what follows. PCRE has been changed to follow suit. However, if it
32    finds options settings right at the start of the pattern, it extracts them into
33    the global options, as before. Thus, they show up in the info data.
34    
35    8. Added support for the \Q...\E escape sequence. Characters in between are
36    treated as literals. This is slightly different from Perl in that $ and @ are
37    also handled as literals inside the quotes. In Perl, they will cause variable
38    interpolation. Note the following examples:
39    
40        Pattern            PCRE matches      Perl matches
41    
42        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
43        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
44        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
45    
46    For compatibility with Perl, \Q...\E sequences are recognized inside character
47    classes as well as outside them.
48    
49    9. Re-organized 3 code statements in pcretest to avoid "overflow in
50    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
51    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
52    signed/unsigned warnings.
53    
54    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
55    option for pcretest, so I've replaced it by a simple function that does just
56    that job.
57    
58    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
59    "pcregrep -".
60    
61    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
62    Java package. This provides some syntactic sugar for simple cases of what my
63    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
64    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
65    item, you can use this simplified notation. Note that only makes sense with
66    greedy quantifiers. Consequently, the use of the possessive quantifier forces
67    greediness, whatever the setting of the PCRE_UNGREEDY option.
68    
69    13. A change of greediness default within a pattern was not taking effect at
70    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
71    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
72    was abstracted outside.
73    
74    14. PCRE now supports the \G assertion. It is true when the current matching
75    position is at the start point of the match. This differs from \A when the
76    starting offset is non-zero. Used with the /g option of pcretest (or similar
77    code), it works in the same way as it does for Perl's /g option. If all
78    alternatives of a regex begin with \G, the expression is anchored to the start
79    match position, and the "anchored" flag is set in the compiled expression.
80    
81    15. Some bugs concerning the handling of certain option changes within patterns
82    have been fixed. These applied to options other than (?ims). For example,
83    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
84    been the other way round. Some of this was related to change 7 above.
85    
86    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
87    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
88    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
89    POSIX classes only within a class (e.g. /[[:alpha:]]/).
90    
91    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
92    mode. Unlike ".", it always matches newline, whatever the setting of
93    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
94    assertions. Perl allows it, but it doesn't (in general) work because it can't
95    calculate the length of the lookbehind. At least, that's the case for Perl
96    5.8.0 - I've been told they are going to document that it doesn't work in
97    future.
98    
99    18. Added an error diagnosis for escapes that PCRE does not support: these are
100    \L, \l, \N, \P, \p, \U, \u, and \X.
101    
102    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
103    reading past the end of the pattern in cases such as /[abcd/.
104    
105    20. PCRE was getting more memory than necessary for patterns with classes that
106    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
107    
108    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
109    compiling PCRE for use with Virtual Pascal.
110    
111    22. Small fix to the Makefile to make it work properly if the build is done
112    outside the source tree.
113    
114    23. Added a new extension: a condition to go with recursion. If a conditional
115    subpattern starts with (?(R) the "true" branch is used if recursion has
116    happened, whereas the "false" branch is used only at the top level.
117    
118    24. When there was a very long string of literal characters (over 255 bytes
119    without UTF support, over 250 bytes with UTF support), the computation of how
120    much memory was required could be incorrect, leading to segfaults or other
121    strange effects.
122    
123    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
124    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
125    there was a subsequent back reference to those brackets. This meant that, for
126    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
127    possible to check for precisely this case. All we can do is abandon the
128    optimization if .* occurs inside capturing brackets when there are any back
129    references whatsoever. (See below for a better fix that came later.)
130    
131    26. The handling of the optimization for finding the first character of a
132    non-anchored pattern, and for finding a character that is required later in the
133    match were failing in some cases. This didn't break the matching; it just
134    failed to optimize when it could. The way this is done has been re-implemented.
135    
136    27. Fixed typo in error message for invalid (?R item (it said "(?p").
137    
138    28. Added a new feature that provides some of the functionality that Perl
139    provides with (?{...}). The facility is termed a "callout". The way it is done
140    in PCRE is for the caller to provide an optional function, by setting
141    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
142    global variable. By default it is unset, which disables all calling out. To get
143    the function called, the regex must include (?C) at appropriate points. This
144    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
145    This provides a means of identifying different callout points. When PCRE
146    reaches such a point in the regex, if pcre_callout has been set, the external
147    function is called. It is provided with data in a structure called
148    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
149    matching continues; if it returns a non-zero value, the match at the current
150    point fails. However, backtracking will occur if possible. [This was changed
151    later and other features added - see item 49 below.]
152    
153    29. pcretest is upgraded to test the callout functionality. It provides a
154    callout function that displays information. By default, it shows the start of
155    the match and the current position in the text. There are some new data escapes
156    to vary what happens:
157    
158        \C+         in addition, show current contents of captured substrings
159        \C-         do not supply a callout function
160        \C!n        return 1 when callout number n is reached
161        \C!n!m      return 1 when callout number n is reached for the mth time
162    
163    30. If pcregrep was called with the -l option and just a single file name, it
164    output "<stdin>" if a match was found, instead of the file name.
165    
166    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
167    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
168    pcre_exec(). This saves a malloc/free per call. The default value of
169    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
170    when configuring.
171    
172    32. The default maximum size of a compiled pattern is 64K. There have been a
173    few cases of people hitting this limit. The code now uses macros to handle the
174    storing of links as offsets within the compiled pattern. It defaults to 2-byte
175    links, but this can be changed to 3 or 4 bytes by --with-link-size when
176    configuring. Tests 2 and 5 work only with 2-byte links because they output
177    debugging information about compiled patterns.
178    
179    33. Internal code re-arrangements:
180    
181    (a) Moved the debugging function for printing out a compiled regex into
182        its own source file (printint.c) and used #include to pull it into
183        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
184        separate copies.
185    
186    (b) Defined the list of op-code names for debugging as a macro in
187        internal.h so that it is next to the definition of the opcodes.
188    
189    (c) Defined a table of op-code lengths for simpler skipping along compiled
190        code. This is again a macro in internal.h so that it is next to the
191        definition of the opcodes.
192    
193    34. Added support for recursive calls to individual subpatterns, along the
194    lines of Robin Houston's patch (but implemented somewhat differently).
195    
196    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
197    allow it to read and process whole directories in Win32. This code was
198    contributed by Lionel Fourquaux; it has not been tested by me.
199    
200    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
201    used to name a group. Names consist of alphanumerics and underscores, and must
202    be unique. Back references use the syntax (?P=name) and recursive calls use
203    (?P>name) which is a PCRE extension to the Python extension. Groups still have
204    numbers. The function pcre_fullinfo() can be used after compilation to extract
205    a name/number map. There are three relevant calls:
206    
207      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
208      PCRE_INFO_NAMECOUNT            yields the number of entries
209      PCRE_INFO_NAMETABLE            yields a pointer to the map.
210    
211    The map is a vector of fixed-size entries. The size of each entry depends on
212    the length of the longest name used. The first two bytes of each entry are the
213    group number, most significant byte first. There follows the corresponding
214    name, zero terminated. The names are in alphabetical order.
215    
216    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
217    case instead of 255. Making it the same both with and without UTF-8 support
218    means that the same test output works with both.
219    
220    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
221    calling malloc() with a zero argument.
222    
223    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
224    optimization. I've improved things by keeping a bitmap of backreferences with
225    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
226    fact referenced, the optimization can be applied. It is unlikely that a
227    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
228    the match to follow \n) will appear inside brackets with a number greater than
229    31, but if it does, any back reference > 31 suppresses the optimization.
230    
231    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
232    of disabling numbered capturing parentheses. Any opening parenthesis that is
233    not followed by ? behaves as if it were followed by ?: but named parentheses
234    can still be used for capturing (and they will acquire numbers in the usual
235    way).
236    
237    41. Redesigned the return codes from the match() function into yes/no/error so
238    that errors can be passed back from deep inside the nested calls. A malloc
239    failure while inside a recursive subpattern call now causes the
240    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
241    
242    42. It is now possible to set a limit on the number of times the match()
243    function is called in a call to pcre_exec(). This facility makes it possible to
244    limit the amount of recursion and backtracking, though not in a directly
245    obvious way, because the match() function is used in a number of different
246    circumstances. The count starts from zero for each position in the subject
247    string (for non-anchored patterns). The default limit is, for compatibility, a
248    large number, namely 10 000 000. You can change this in two ways:
249    
250    (a) When configuring PCRE before making, you can use --with-match-limit=n
251        to set a default value for the compiled library.
252    
253    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
254        a different value is set. See 45 below.
255    
256    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
257    
258    43. Added a new function pcre_config(int, void *) to enable run-time extraction
259    of things that can be changed at compile time. The first argument specifies
260    what is wanted and the second points to where the information is to be placed.
261    The current list of available information is:
262    
263      PCRE_CONFIG_UTF8
264    
265    The output is an integer that is set to one if UTF-8 support is available;
266    otherwise it is set to zero.
267    
268      PCRE_CONFIG_NEWLINE
269    
270    The output is an integer that it set to the value of the code that is used for
271    newline. It is either LF (10) or CR (13).
272    
273      PCRE_CONFIG_LINK_SIZE
274    
275    The output is an integer that contains the number of bytes used for internal
276    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
277    
278      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
279    
280    The output is an integer that contains the threshold above which the POSIX
281    interface uses malloc() for output vectors. See item 31 above.
282    
283      PCRE_CONFIG_MATCH_LIMIT
284    
285    The output is an unsigned integer that contains the default limit of the number
286    of match() calls in a pcre_exec() execution. See 42 above.
287    
288    44. pcretest has been upgraded by the addition of the -C option. This causes it
289    to extract all the available output from the new pcre_config() function, and to
290    output it. The program then exits immediately.
291    
292    45. A need has arisen to pass over additional data with calls to pcre_exec() in
293    order to support additional features. One way would have been to define
294    pcre_exec2() (for example) with extra arguments, but this would not have been
295    extensible, and would also have required all calls to the original function to
296    be mapped to the new one. Instead, I have chosen to extend the mechanism that
297    is used for passing in "extra" data from pcre_study().
298    
299    The pcre_extra structure is now exposed and defined in pcre.h. It currently
300    contains the following fields:
301    
302      flags         a bitmap indicating which of the following fields are set
303      study_data    opaque data from pcre_study()
304      match_limit   a way of specifying a limit on match() calls for a specific
305                      call to pcre_exec()
306      callout_data  data for callouts (see 49 below)
307    
308    The flag bits are also defined in pcre.h, and are
309    
310      PCRE_EXTRA_STUDY_DATA
311      PCRE_EXTRA_MATCH_LIMIT
312      PCRE_EXTRA_CALLOUT_DATA
313    
314    The pcre_study() function now returns one of these new pcre_extra blocks, with
315    the actual study data pointed to by the study_data field, and the
316    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
317    before. That is, this change is entirely upwards-compatible and requires no
318    change to existing code.
319    
320    If you want to pass in additional data to pcre_exec(), you can either place it
321    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
322    block.
323    
324    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
325    data string contains the escape sequence \M, pcretest calls pcre_exec() several
326    times with different match limits, until it finds the minimum value needed for
327    pcre_exec() to complete. The value is then output. This can be instructive; for
328    most simple matches the number is quite small, but for pathological cases it
329    gets very large very quickly.
330    
331    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
332    returns the size of the data block pointed to by the study_data field in a
333    pcre_extra block, that is, the value that was passed as the argument to
334    pcre_malloc() when PCRE was getting memory in which to place the information
335    created by pcre_study(). The fourth argument should point to a size_t variable.
336    pcretest has been extended so that this information is shown after a successful
337    pcre_study() call when information about the compiled regex is being displayed.
338    
339    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
340    because what follows is always an absolute path. (Later: it turns out that this
341    is more than cosmetic for MinGW, because it doesn't like empty path
342    components.)
343    
344    49. Some changes have been made to the callout feature (see 28 above):
345    
346    (i)  A callout function now has three choices for what it returns:
347    
348           0  =>  success, carry on matching
349         > 0  =>  failure at this point, but backtrack if possible
350         < 0  =>  serious error, return this value from pcre_exec()
351    
352         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
353         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
354         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
355         use by callout functions. It will never be used by PCRE itself.
356    
357    (ii) The pcre_extra structure (see 45 above) has a void * field called
358         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
359         pcre_callout_block structure has a field of the same name. The contents of
360         the field passed in the pcre_extra structure are passed to the callout
361         function in the corresponding field in the callout block. This makes it
362         easier to use the same callout-containing regex from multiple threads. For
363         testing, the pcretest program has a new data escape
364    
365           \C*n        pass the number n (may be negative) as callout_data
366    
367         If the callout function in pcretest receives a non-zero value as
368         callout_data, it returns that value.
369    
370    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
371    there were some redundant $(CFLAGS) in commands that are now specified as
372    $(LINK), which already includes $(CFLAGS).
373    
374    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
375    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
376    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
377    one-byte characters throughout. Note that case-insensitive matching applies
378    only to characters whose values are less than 256. PCRE doesn't support the
379    notion of cases for higher-valued characters.
380    
381    (i)   A character class whose characters are all within 0-255 is handled as
382          a bit map, and the map is inverted for negative classes. Previously, a
383          character > 255 always failed to match such a class; however it should
384          match if the class was a negative one (e.g. [^ab]). This has been fixed.
385    
386    (ii)  A negated character class with a single character < 255 is coded as
387          "not this character" (OP_NOT). This wasn't working properly when the test
388          character was multibyte, either singly or repeated.
389    
390    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
391          mode, for example: \x{100}{2,3}.
392    
393    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
394          singly or repeated) now correctly test multibyte characters. However,
395          PCRE doesn't recognize any characters with values greater than 255 as
396          digits, spaces, or word characters. Such characters always match \D, \S,
397          and \W, and never match \d, \s, or \w.
398    
399    (v)   Classes may now contain characters and character ranges with values
400          greater than 255. For example: [ab\x{100}-\x{400}].
401    
402    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
403          PCRE in UTF-8 mode.
404    
405    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
406    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
407    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
408    value.)
409    
410    53. The single man page has become too large. I have therefore split it up into
411    a number of separate man pages. These also give rise to individual HTML pages;
412    these are now put in a separate directory, and there is an index.html page that
413    lists them all. Some hyperlinking between the pages has been installed.
414    
415    54. Added convenience functions for handling named capturing parentheses.
416    
417    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
418    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
419    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
420    are faulted.
421    
422    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
423    calling configure. These values are used when compiling the dftables.c program
424    which is run to generate the source of the default character tables. They
425    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
426    you will need to set these values.
427    
428    57. Updated the building process for Windows DLL, as provided by Fred Cox.
429    
430    
431    Version 3.9 02-Jan-02
432    ---------------------
433    
434    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
435    
436    2. If --disable-static was given, the building process failed when trying to
437    build pcretest and pcregrep. (For some reason it was using libtool to compile
438    them, which is not right, as they aren't part of the library.)
439    
440    
441    Version 3.8 18-Dec-01
442    ---------------------
443    
444    1. The experimental UTF-8 code was completely screwed up. It was packing the
445    bytes in the wrong order. How dumb can you get?
446    
447    
448    Version 3.7 29-Oct-01
449    ---------------------
450    
451    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
452    This caused pcretest, when used on the test data, to segfault. Unfortunately,
453    this didn't happen under Solaris 8, where I normally test things.
454    
455    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
456    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
457    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
458    this fix an hour or so after the initial 3.7 release.)
459    
460    
461    Version 3.6 23-Oct-01
462    ---------------------
463    
464    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
465    offsets passed as NULL with zero offset count.
466    
467    2. The config.guess and config.sub files had not been updated when I moved to
468    the latest autoconf.
469    
470    
471    Version 3.5 15-Aug-01
472    ---------------------
473    
474    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
475    had been forgotten.
476    
477    2. By using declared but undefined structures, we can avoid using "void"
478    definitions in pcre.h while keeping the internal definitions of the structures
479    private.
480    
481    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
482    user point of view, this means that both static and shared libraries are built
483    by default, but this can be individually controlled. More of the work of
484    handling this static/shared cases is now inside libtool instead of PCRE's make
485    file.
486    
487    4. The pcretest utility is now installed along with pcregrep because it is
488    useful for users (to test regexs) and by doing this, it automatically gets
489    relinked by libtool. The documentation has been turned into a man page, so
490    there are now .1, .txt, and .html versions in /doc.
491    
492    5. Upgrades to pcregrep:
493       (i)   Added long-form option names like gnu grep.
494       (ii)  Added --help to list all options with an explanatory phrase.
495       (iii) Added -r, --recursive to recurse into sub-directories.
496       (iv)  Added -f, --file to read patterns from a file.
497    
498    6. pcre_exec() was referring to its "code" argument before testing that
499    argument for NULL (and giving an error if it was NULL).
500    
501    7. Upgraded Makefile.in to allow for compiling in a different directory from
502    the source directory.
503    
504    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
505    options bits, the pointer it was passed was to an int instead of to an unsigned
506    long int. This mattered only on 64-bit systems.
507    
508    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
509    generated) instead of pcre.in, which it its source. Also made the same change
510    in several of the .c files.
511    
512    10. A new release of gcc defines printf() as a macro, which broke pcretest
513    because it had an ifdef in the middle of a string argument for printf(). Fixed
514    by using separate calls to printf().
515    
516    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
517    script, to force use of CR or LF instead of \n in the source. On non-Unix
518    systems, the value can be set in config.h.
519    
520    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
521    absolute limit. Changed the text of the error message to make this clear, and
522    likewise updated the man page.
523    
524    13. The limit of 99 on the number of capturing subpatterns has been removed.
525    The new limit is 65535, which I hope will not be a "real" limit.
526    
527    
528    Version 3.4 22-Aug-00
529    ---------------------
530    
531    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
532    
533    2. Diagnose condition (?(0) as an error instead of crashing on matching.
534    
535    
536    Version 3.3 01-Aug-00
537    ---------------------
538    
539    1. If an octal character was given, but the value was greater than \377, it
540    was not getting masked to the least significant bits, as documented. This could
541    lead to crashes in some systems.
542    
543    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
544    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
545    
546    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
547    These just pass their arguments on to (pcre_free)(), but they are provided
548    because some uses of PCRE bind it to non-C systems that can call its functions,
549    but cannot call free() or pcre_free() directly.
550    
551    4. Add "make test" as a synonym for "make check". Corrected some comments in
552    the Makefile.
553    
554    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
555    Makefile.
556    
557    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
558    command called pgrep for grepping around the active processes.
559    
560    7. Added the beginnings of support for UTF-8 character strings.
561    
562    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
563    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
564    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
565    out for the ar command.)
566    
567    
568    Version 3.2 12-May-00
569    ---------------------
570    
571    This is purely a bug fixing release.
572    
573    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
574    of ZA. This was just one example of several cases that could provoke this bug,
575    which was introduced by change 9 of version 2.00. The code for breaking
576    infinite loops after an iteration that matches an empty string was't working
577    correctly.
578    
579    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
580    when matched against abbab (for example). After matching an empty string, it
581    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
582    caused it to match further down the string than it should.
583    
584    3. The code contained an inclusion of sys/types.h. It isn't clear why this
585    was there because it doesn't seem to be needed, and it causes trouble on some
586    systems, as it is not a Standard C header. It has been removed.
587    
588    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
589    were reported on the Macintosh. The changes were from
590    
591      while ((c = *(++ptr)) != 0 && c != '\n');
592    to
593      while ((c = *(++ptr)) != 0 && c != '\n') ;
594    
595    Totally extraordinary, but if that's what it takes...
596    
597    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
598    available. Added HAVE_BCOPY and an autoconf test for it; if neither
599    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
600    assumes the way PCRE uses memmove() (always moving upwards).
601    
602    6. PCRE is being used in one environment where strchr() is not available. There
603    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
604    faster code anyway.
605    
606    
607    Version 3.1 09-Feb-00
608    ---------------------
609    
610    The only change in this release is the fixing of some bugs in Makefile.in for
611    the "install" target:
612    
613    (1) It was failing to install pcreposix.h.
614    
615    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
616    
617    
618    Version 3.0 01-Feb-00
619    ---------------------
620    
621    1. Add support for the /+ modifier to perltest (to output $` like it does in
622    pcretest).
623    
624    2. Add support for the /g modifier to perltest.
625    
626    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
627    matches null strings.
628    
629    4. Fix perltest so that it doesn't do unwanted things when fed an empty
630    pattern. Perl treats empty patterns specially - it reuses the most recent
631    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
632    effect.
633    
634    5. The POSIX interface was broken in that it was just handing over the POSIX
635    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
636    required a bigger vector, with some working space on the end. This means that
637    the POSIX wrapper now has to get and free some memory, and copy the results.
638    
639    6. Added some simple autoconf support, placing the test data and the
640    documentation in separate directories, re-organizing some of the
641    information files, and making it build pcre-config (a GNU standard). Also added
642    libtool support for building PCRE as a shared library, which is now the
643    default.
644    
645    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
646    09 are not valid octal constants. Single digits will be used for minor values
647    less than 10.
648    
649    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
650    existing programs that set these in the POSIX interface can use PCRE without
651    modification.
652    
653    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
654    return all that pcre_info() returns, plus additional data. The pcre_info()
655    function is retained for compatibility, but is considered to be obsolete.
656    
657    10. Added experimental recursion feature (?R) to handle one common case that
658    Perl 5.6 will be able to do with (?p{...}).
659    
660    11. Added support for POSIX character classes like [:alpha:], which Perl is
661    adopting.
662    
663    
664    Version 2.08 31-Aug-99
665    ----------------------
666    
667    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
668    trying to match at the startoffset position, but instead was moving forward to
669    the next newline as if a previous match had failed.
670    
671    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
672    and could get into a loop if a null string was matched other than at the start
673    of the subject.
674    
675    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
676    be distinguished at compile time, and for completeness also added PCRE_DATE.
677    
678    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
679    in GnuWin32 environments.
680    
681    
682    Version 2.07 29-Jul-99
683    ----------------------
684    
685    1. The documentation is now supplied in plain text form and HTML as well as in
686    the form of man page sources.
687    
688    2. C++ compilers don't like assigning (void *) values to other pointer types.
689    In particular this affects malloc(). Although there is no problem in Standard
690    C, I've put in casts to keep C++ compilers happy.
691    
692    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
693    should be (const char *).
694    
695    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
696    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
697    However, I haven't made this a standard facility. The documentation doesn't
698    mention it, and the Makefile doesn't support it.
699    
700    5. The Makefile now contains an "install" target, with editable destinations at
701    the top of the file. The pcretest program is not installed.
702    
703    6. pgrep -V now gives the PCRE version number and date.
704    
705    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
706    causing the entire string to be ignored, instead of just the last character.
707    
708    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
709    non-matching string, it can take a very, very long time, even for strings of
710    quite modest length, because of the nested recursion. PCRE now does better in
711    some of these cases. It does this by remembering the last required literal
712    character in the pattern, and pre-searching the subject to ensure it is present
713    before running the real match. In other words, it applies a heuristic to detect
714    some types of certain failure quickly, and in the above example, if presented
715    with a string that has no trailing " it gives "no match" very quickly.
716    
717    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
718    other alternatives are tried instead.
719    
720    
721    Version 2.06 09-Jun-99
722    ----------------------
723    
724    1. Change pcretest's output for amount of store used to show just the code
725    space, because the remainder (the data block) varies in size between 32-bit and
726    64-bit systems.
727    
728    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
729    start matching at. This allows lookbehinds to work when searching for multiple
730    occurrences in a string.
731    
732    3. Added additional options to pcretest for testing multiple occurrences:
733    
734       /+   outputs the rest of the string that follows a match
735       /g   loops for multiple occurrences, using the new startoffset argument
736       /G   loops for multiple occurrences by passing an incremented pointer
737    
738    4. PCRE wasn't doing the "first character" optimization for patterns starting
739    with \b or \B, though it was doing it for other lookbehind assertions. That is,
740    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
741    the letter 'x'. On long subject strings, this gives a significant speed-up.
742    
743    
744    Version 2.05 21-Apr-99
745    ----------------------
746    
747    1. Changed the type of magic_number from int to long int so that it works
748    properly on 16-bit systems.
749    
750    2. Fixed a bug which caused patterns starting with .* not to work correctly
751    when the subject string contained newline characters. PCRE was assuming
752    anchoring for such patterns in all cases, which is not correct because .* will
753    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
754    DOTALL is set at top level; otherwise it knows that patterns starting with .*
755    must be retried after every newline in the subject.
756    
757    
758  Version 2.04 18-Feb-99  Version 2.04 18-Feb-99
759  ----------------------  ----------------------

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