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ChangeLog for PCRE
Version 8.13 16-Aug-2011
1. The Unicode data tables have been updated to Unicode 6.0.0.
2. Two minor typos in pcre_internal.h have been fixed.
3. Added #include <string.h> to,, and They are needed for strcmp(), memset(), and strchr()
in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
4. There were a number of related bugs in the code for matching backrefences
caselessly in UTF-8 mode when codes for the characters concerned were
different numbers of bytes. For example, U+023A and U+2C65 are an upper
and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
(a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
2-byte code at the end of the subject (it thought there wasn't enough data
5. Comprehensive information about what went wrong is now returned by
pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
as the output vector has at least 2 elements. The offset of the start of
the failing character and a reason code are placed in the vector.
6. When the UTF-8 string check fails for pcre_compile(), the offset that is
now returned is for the first byte of the failing character, instead of the
last byte inspected. This is an incompatible change, but I hope it is small
enough not to be a problem. It makes the returned offset consistent with
pcre_exec() and pcre_dfa_exec().
7. pcretest now gives a text phrase as well as the error number when
pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
failure, the offset and reason code are output.
8. When \R was used with a maximizing quantifier it failed to skip backwards
over a \r\n pair if the subsequent match failed. Instead, it just skipped
back over a single character (\n). This seems wrong (because it treated the
two characters as a single entity when going forwards), conflicts with the
documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
has been changed.
9. Some internal refactoring has changed the processing so that the handling
of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
time (the PCRE_DOTALL option was changed this way some time ago: version
7.7 change 16). This has made it possible to abolish the OP_OPT op code,
which was always a bit of a fudge. It also means that there is one less
argument for the match() function, which reduces its stack requirements
slightly. This change also fixes an incompatibility with Perl: the pattern
(?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
10. More internal refactoring has drastically reduced the number of recursive
calls to match() for possessively repeated groups such as (abc)++ when
using pcre_exec().
11. While implementing 10, a number of bugs in the handling of groups were
discovered and fixed:
(?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
(a|)*(?1) gave a compile-time internal error.
((a|)+)+ did not notice that the outer group could match an empty string.
(^a|^)+ was not marked as anchored.
(.*a|.*)+ was not marked as matching at start or after a newline.
12. Yet more internal refactoring has removed another argument from the match()
function. Special calls to this function are now indicated by setting a
value in a variable in the "match data" data block.
13. Be more explicit in pcre_study() instead of relying on "default" for
opcodes that mean there is no starting character; this means that when new
ones are added and accidentally left out of pcre_study(), testing should
pick them up.
14. The -s option of pcretest has been documented for ages as being an old
synonym of -m (show memory usage). I have changed it to mean "force study
for every regex", that is, assume /S for every regex. This is similar to -i
and -d etc. It's slightly incompatible, but I'm hoping nobody is still
using it. It makes it easier to run collections of tests with and without
study enabled, and thereby test pcre_study() more easily. All the standard
tests are now run with and without -s (but some patterns can be marked as
"never study" - see 20 below).
15. When (*ACCEPT) was used in a subpattern that was called recursively, the
restoration of the capturing data to the outer values was not happening
16. If a recursively called subpattern ended with (*ACCEPT) and matched an
empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
pattern had matched an empty string, and so incorrectly returned a no
17. There was optimizing code for the last branch of non-capturing parentheses,
and also for the obeyed branch of a conditional subexpression, which used
tail recursion to cut down on stack usage. Unfortunately, now that there is
the possibility of (*THEN) occurring in these branches, tail recursion is
no longer possible because the return has to be checked for (*THEN). These
two optimizations have therefore been removed.
18. If a pattern containing \R was studied, it was assumed that \R always
matched two bytes, thus causing the minimum subject length to be
incorrectly computed because \R can also match just one byte.
19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
was incorrectly computed.
20. If /S is present twice on a test pattern in pcretest input, it now
*disables* studying, thereby overriding the use of -s on the command line
(see 14 above). This is necessary for one or two tests to keep the output
identical in both cases.
21. When (*ACCEPT) was used in an assertion that matched an empty string and
PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
22. When an atomic group that contained a capturing parenthesis was
successfully matched, but the branch in which it appeared failed, the
capturing was not being forgotten if a higher numbered group was later
captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
group 1 to "a", when in fact it should be unset. This applied to multi-
branched capturing and non-capturing groups, repeated or not, and also to
positive assertions (capturing in negative assertions does not happen
in PCRE) and also to nested atomic groups.
23. Add the ++ qualifier feature to pcretest, to show the remainder of the
subject after a captured substring, to make it easier to tell which of a
number of identical substrings has been captured.
24. The way atomic groups are processed by pcre_exec() has been changed so that
if they are repeated, backtracking one repetition now resets captured
values correctly. For example, if ((?>(a+)b)+aabab) is matched against
"aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
"aaa". Previously, it would have been "a". As part of this code
refactoring, the way recursive calls are handled has also been changed.
25. If an assertion condition captured any substrings, they were not passed
back unless some other capturing happened later. For example, if
(?(?=(a))a) was matched against "a", no capturing was returned.
26. When studying a pattern that contained subroutine calls or assertions,
the code for finding the minimum length of a possible match was handling
direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
group 1 called group 2 while simultaneously a separate group 2 called group
1). A stack overflow occurred in this case. I have fixed this by limiting
the recursion depth to 10.
27. Updated RunTest.bat in the distribution to the version supplied by Tom
Fortmann. This supports explicit test numbers on the command line, and has
argument validation and error reporting.
28. An instance of \X with an unlimited repeat could fail if at any point the
first character it looked at was a mark character.
29. Some minor code refactoring concerning Unicode properties and scripts
should reduce the stack requirement of match() slightly.
30. Added the '=' option to pcretest to check the setting of unused capturing
slots at the end of the pattern, which are documented as being -1, but are
not included in the return count.
31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
compiled something random. Now it gives a compile-time error (as does
32. A *MARK encountered during the processing of a positive assertion is now
recorded and passed back (compatible with Perl).
33. If --only-matching or --colour was set on a pcregrep call whose pattern
had alternative anchored branches, the search for a second match in a line
was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
matched the line "0102" twice. The same bug affected patterns that started
with a backwards assertion. For example /\b01|\b02/ also matched "0102"
34. Previously, PCRE did not allow quantification of assertions. However, Perl
does, and because of capturing effects, quantifying parenthesized
assertions may at times be useful. Quantifiers are now allowed for
parenthesized assertions.
35. A minor code tidy in pcre_compile() when checking options for \R usage.
36. \g was being checked for fancy things in a character class, when it should
just be a literal "g".
37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
appearance of a nested POSIX class supersedes an apparent external class.
For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
unescaped square brackets may also appear as part of class names. For
example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
more like Perl.
38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
was because it thought it was \N{name}, which is not supported).
39. Add minix to OS list not supporting the -S option in pcretest.
40. PCRE tries to detect cases of infinite recursion at compile time, but it
cannot analyze patterns in sufficient detail to catch mutual recursions
such as ((?1))((?2)). There is now a runtime test that gives an error if a
subgroup is called recursively as a subpattern for a second time at the
same position in the subject string. In previous releases this might have
been caught by the recursion limit, or it might have run out of stack.
41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
happen only once. PCRE was, however incorrectly giving a compile time error
"recursive call could loop indefinitely" because it cannot analyze the
pattern in sufficient detail. The compile time test no longer happens when
PCRE is compiling a conditional subpattern, but actual runaway loops are
now caught at runtime (see 40 above).
42. It seems that Perl allows any characters other than a closing parenthesis
to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
has been changed to be the same.
43. Updated to put in more quoting round AC_LANG_PROGRAM etc. so
as not to get warnings when is called. Also changed
AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
44. To help people who use pcregrep to scan files containing exceedingly long
lines, the following changes have been made:
(a) The default value of the buffer size parameter has been increased from
8K to 20K. (The actual buffer used is three times this size.)
(b) The default can be changed by ./configure --with-pcregrep-bufsize when
PCRE is built.
(c) A --buffer-size=n option has been added to pcregrep, to allow the size
to be set at run time.
(d) Numerical values in pcregrep options can be followed by K or M, for
example --buffer-size=50K.
(e) If a line being scanned overflows pcregrep's buffer, an error is now
given and the return code is set to 2.
45. Add a pointer to the latest mark to the callout data block.
46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
partial match of an empty string instead of no match. This was specific to
the use of ".".
47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
complete match instead of a partial match. This bug was dependent on both
the PCRE_UTF8 and PCRE_DOTALL options being set.
48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
starting byte set, because \b was not being ignored.
Version 8.12 15-Jan-2011
1. Fixed some typos in the markup of the man pages, and wrote a script that
checks for such things as part of the documentation building process.
2. On a big-endian 64-bit system, pcregrep did not correctly process the
--match-limit and --recursion-limit options (added for 8.11). In
particular, this made one of the standard tests fail. (The integer value
went into the wrong half of a long int.)
3. If the --colour option was given to pcregrep with -v (invert match), it
did strange things, either producing crazy output, or crashing. It should,
of course, ignore a request for colour when reporting lines that do not
4. Another pcregrep bug caused similar problems if --colour was specified with
-M (multiline) and the pattern match finished with a line ending.
5. In pcregrep, when a pattern that ended with a literal newline sequence was
matched in multiline mode, the following line was shown as part of the
match. This seems wrong, so I have changed it.
6. Another pcregrep bug in multiline mode, when --colour was specified, caused
the check for further matches in the same line (so they could be coloured)
to overrun the end of the current line. If another match was found, it was
incorrectly shown (and then shown again when found in the next line).
7. If pcregrep was compiled under Windows, there was a reference to the
function pcregrep_exit() before it was defined. I am assuming this was
the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
reported by a user. I've moved the definition above the reference.
Version 8.11 10-Dec-2010
1. (*THEN) was not working properly if there were untried alternatives prior
to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
backtracked to try for "b" instead of moving to the next alternative branch
at the same level (in this case, to look for "c"). The Perl documentation
is clear that when (*THEN) is backtracked onto, it goes to the "next
alternative in the innermost enclosing group".
2. (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
such as (A(*COMMIT)B(*THEN)C|D) any failure after matching A should
result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
(*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
3. If \s appeared in a character class, it removed the VT character from
the class, even if it had been included by some previous item, for example
in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
of \s, but is part of the POSIX "space" class.)
4. A partial match never returns an empty string (because you can always
match an empty string at the end of the subject); however the checking for
an empty string was starting at the "start of match" point. This has been
changed to the "earliest inspected character" point, because the returned
data for a partial match starts at this character. This means that, for
example, /(?<=abc)def/ gives a partial match for the subject "abc"
(previously it gave "no match").
5. Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
previously a full match would be given. However, setting PCRE_PARTIAL_HARD
has an implication that the given string is incomplete (because a partial
match is preferred over a full match). For this reason, these items now
give a partial match in this situation. [Aside: previously, the one case
/t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
match rather than a full match, which was wrong by the old rules, but is
now correct.]
6. There was a bug in the handling of #-introduced comments, recognized when
PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
places in pcre_compile().
7. Related to (6) above, when pcre_compile() was skipping #-introduced
comments when looking ahead for named forward references to subpatterns,
the only newline sequence it recognized was NL. It now handles newlines
according to the set newline convention.
8. SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
former, but used strtoul(), whereas pcretest avoided strtoul() but did not
cater for a lack of strerror(). These oversights have been fixed.
9. Added --match-limit and --recursion-limit to pcregrep.
10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
11. When the -o option was used, pcregrep was setting a return code of 1, even
when matches were found, and --line-buffered was not being honoured.
12. Added an optional parentheses number to the -o and --only-matching options
of pcregrep.
13. Imitating Perl's /g action for multiple matches is tricky when the pattern
can match an empty string. The code to do it in pcretest and pcredemo
needed fixing:
(a) When the newline convention was "crlf", pcretest got it wrong, skipping
only one byte after an empty string match just before CRLF (this case
just got forgotten; "any" and "anycrlf" were OK).
(b) The pcretest code also had a bug, causing it to loop forever in UTF-8
mode when an empty string match preceded an ASCII character followed by
a non-ASCII character. (The code for advancing by one character rather
than one byte was nonsense.)
(c) The pcredemo.c sample program did not have any code at all to handle
the cases when CRLF is a valid newline sequence.
14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
as a starting offset was within the subject string. There is now a new
error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
negative or greater than the length of the string. In order to test this,
pcretest is extended to allow the setting of negative starting offsets.
15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
starting offset points to the beginning of a UTF-8 character was
unnecessarily clumsy. I tidied it up.
16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
17. Nobody had reported that the --include_dir option, which was added in
release 7.7 should have been called --include-dir (hyphen, not underscore)
for compatibility with GNU grep. I have changed it to --include-dir, but
left --include_dir as an undocumented synonym, and the same for
--exclude-dir, though that is not available in GNU grep, at least as of
release 2.5.4.
18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
characters from a string of bytes) have been redefined so as not to use
loops, in order to improve performance in some environments. At the same
time, I abstracted some of the common code into auxiliary macros to save
repetition (this should not affect the compiled code).
19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
compile-time error is now given if \c is not followed by an ASCII
character, that is, a byte less than 128. (In EBCDIC mode, the code is
different, and any byte value is allowed.)
20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
START_OPTIMIZE option, which is now allowed at compile time - but just
passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
to pcregrep and other applications that have no direct access to PCRE
options. The new /Y option in pcretest sets this option when calling
21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
back references. Groups containing recursive back references were forced to
be atomic by that change, but in the case of named groups, the amount of
memory required was incorrectly computed, leading to "Failed: internal
error: code overflow". This has been fixed.
22. Some patches to pcre_stringpiece.h,, and
pcretest.c, to avoid build problems in some Borland environments.
Version 8.10 25-Jun-2010
1. Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
2. (*ACCEPT) was not working when inside an atomic group.
3. Inside a character class, \B is treated as a literal by default, but
faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
causes the error). The code is unchanged, but I tidied the documentation.
4. Inside a character class, PCRE always treated \R and \X as literals,
whereas Perl faults them if its -w option is set. I have changed PCRE so
that it faults them when PCRE_EXTRA is set.
5. Added support for \N, which always matches any character other than
newline. (It is the same as "." when PCRE_DOTALL is not set.)
6. When compiling pcregrep with newer versions of gcc which may have
FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
declared with attribute warn_unused_result" were given. Just casting the
result to (void) does not stop the warnings; a more elaborate fudge is
needed. I've used a macro to implement this.
7. Minor change to pcretest.c to avoid a compiler warning.
8. Added four artifical Unicode properties to help with an option to make
\s etc use properties (see next item). The new properties are: Xan
(alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
9. Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
use Unicode properties. (*UCP) at the start of a pattern can be used to set
this option. Modified pcretest to add /W to test this facility. Added
REG_UCP to make it available via the POSIX interface.
10. Added --line-buffered to pcregrep.
11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
studied, and the match started with a letter with a code point greater than
127 whose first byte was different to the first byte of the other case of
the letter, the other case of this starting letter was not recognized
12. If a pattern that was studied started with a repeated Unicode property
test, for example, \p{Nd}+, there was the theoretical possibility of
setting up an incorrect bitmap of starting bytes, but fortunately it could
not have actually happened in practice until change 8 above was made (it
added property types that matched character-matching opcodes).
13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
possible starting bytes for non-anchored patterns.
14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
\R, and also a number of cases that involve Unicode properties, both
explicit and implicit when PCRE_UCP is set.
15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
input, it could crash or give wrong results if characters with values
greater than 0xc0 were present in the subject string. (Detail: it assumed
UTF-8 input when processing these items.)
16. Added a lot of (int) casts to avoid compiler warnings in systems where
size_t is 64-bit (#991).
17. Added a check for running out of memory when PCRE is compiled with
--disable-stack-for-recursion (#990).
18. If the last data line in a file for pcretest does not have a newline on
the end, a newline was missing in the output.
19. The default pcre_chartables.c file recognizes only ASCII characters (values
less than 128) in its various bitmaps. However, there is a facility for
generating tables according to the current locale when PCRE is compiled. It
turns out that in some environments, 0x85 and 0xa0, which are Unicode space
characters, are recognized by isspace() and therefore were getting set in
these tables, and indeed these tables seem to approximate to ISO 8859. This
caused a problem in UTF-8 mode when pcre_study() was used to create a list
of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
which of course cannot start UTF-8 characters. I have changed the code so
that only real ASCII characters (less than 128) and the correct starting
bytes for UTF-8 encodings are set for characters greater than 127 when in
UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
20. Added the /T option to pcretest so as to be able to run tests with non-
standard character tables, thus making it possible to include the tests
used for 19 above in the standard set of tests.
21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
reference to a subpattern the other side of a comment that contains an
opening parenthesis caused either an internal compiling error, or a
reference to the wrong subpattern.
Version 8.02 19-Mar-2010
1. The Unicode data tables have been updated to Unicode 5.2.0.
2. Added the option --libs-cpp to pcre-config, but only when C++ support is
3. Updated the licensing terms in the pcregexp.pas file, as agreed with the
original author of that file, following a query about its status.
4. On systems that do not have stdint.h (e.g. Solaris), check for and include
inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
5. A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
quantifier applied to a forward-referencing subroutine call, could compile
incorrect code or give the error "internal error: previously-checked
referenced subpattern not found".
6. Both MS Visual Studio and Symbian OS have problems with initializing
variables to point to external functions. For these systems, therefore,
pcre_malloc etc. are now initialized to local functions that call the
relevant global functions.
7. There were two entries missing in the vectors called coptable and poptable
in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
I've fixed the data, and added a kludgy way of testing at compile time that
the lengths are correct (equal to the number of opcodes).
8. Following on from 7, I added a similar kludge to check the length of the
eint vector in pcreposix.c.
9. Error texts for pcre_compile() are held as one long string to avoid too
much relocation at load time. To find a text, the string is searched,
counting zeros. There was no check for running off the end of the string,
which could happen if a new error number was added without updating the
10. \K gave a compile-time error if it appeared in a lookbehind assersion.
11. \K was not working if it appeared in an atomic group or in a group that
was called as a "subroutine", or in an assertion. Perl 5.11 documents that
\K is "not well defined" if used in an assertion. PCRE now accepts it if
the assertion is positive, but not if it is negative.
12. Change 11 fortuitously reduced the size of the stack frame used in the
"match()" function of pcre_exec.c by one pointer. Forthcoming
implementation of support for (*MARK) will need an extra pointer on the
stack; I have reserved it now, so that the stack frame size does not
13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
item in branch that calls a recursion is a subroutine call - as in the
second branch in the above example - was incorrectly given the compile-
time error "recursive call could loop indefinitely" because pcre_compile()
was not correctly checking the subroutine for matching a non-empty string.
14. The checks for overrunning compiling workspace could trigger after an
overrun had occurred. This is a "should never occur" error, but it can be
triggered by pathological patterns such as hundreds of nested parentheses.
The checks now trigger 100 bytes before the end of the workspace.
15. Fix typo in "srtoq" should be "strtoq".
Version 8.01 19-Jan-2010
1. If a pattern contained a conditional subpattern with only one branch (in
particular, this includes all (*DEFINE) patterns), a call to pcre_study()
computed the wrong minimum data length (which is of course zero for such
subpatterns). This could cause incorrect "no match" results.
2. For patterns such as (?i)a(?-i)b|c where an option setting at the start of
the pattern is reset in the first branch, pcre_compile() failed with
"internal error: code overflow at offset...". This happened only when
the reset was to the original external option setting. (An optimization
abstracts leading options settings into an external setting, which was the
cause of this.)
3. A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
assertion pattern did not match (meaning that the assertion was true), it
was incorrectly treated as false if the SKIP had been reached during the
matching. This also applied to assertions used as conditions.
4. If an item that is not supported by pcre_dfa_exec() was encountered in an
assertion subpattern, including such a pattern used as a condition,
unpredictable results occurred, instead of the error return
5. The C++ GlobalReplace function was not working like Perl for the special
situation when an empty string is matched. It now does the fancy magic
stuff that is necessary.
6. In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
removed. (These were left over from very, very early versions of PCRE.)
7. Some cosmetic changes to the code to make life easier when compiling it
as part of something else:
(a) Change DEBUG to PCRE_DEBUG.
(b) In pcre_compile(), rename the member of the "branch_chain" structure
called "current" as "current_branch", to prevent a collision with the
Linux macro when compiled as a kernel module.
(c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
prevent a collision with the Linux macro when compiled as a kernel
8. In pcre_compile() there are some checks for integer overflows that used to
cast potentially large values to (double). This has been changed to that
when building, a check for int64_t is made, and if it is found, it is used
instead, thus avoiding the use of floating point arithmetic. (There is no
other use of FP in PCRE.) If int64_t is not found, the fallback is to
9. Added two casts to avoid signed/unsigned warnings from VS Studio Express
2005 (difference between two addresses compared to an unsigned value).
10. Change the standard AC_CHECK_LIB test for libbz2 in to a
custom one, because of the following reported problem in Windows:
- libbz2 uses the Pascal calling convention (WINAPI) for the functions
under Win32.
- The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
therefore missing the function definition.
- The compiler thus generates a "C" signature for the test function.
- The linker fails to find the "C" function.
- PCRE fails to configure if asked to do so against libbz2.
11. When running libtoolize from libtool-2.2.6b as part of, these
messages were output:
Consider adding `AC_CONFIG_MACRO_DIR([m4])' to and
rerunning libtoolize, to keep the correct libtool macros in-tree.
Consider adding `-I m4' to ACLOCAL_AMFLAGS in
I have done both of these things.
12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
most of the time, it *can* run out if it is given a pattern that contains a
runaway infinite recursion. I updated the discussion in the pcrestack man
13. Now that we have gone to the x.xx style of version numbers, the minor
version may start with zero. Using 08 or 09 is a bad idea because users
might check the value of PCRE_MINOR in their code, and 08 or 09 may be
interpreted as invalid octal numbers. I've updated the previous comment in, and also added a check that gives an error if 08 or 09 are
14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
causing partial matching to fail when the end of the subject matched \W
in a UTF-8 pattern where \W was quantified with a minimum of 3.
15. There were some discrepancies between the declarations in pcre_internal.h
of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
their definitions. The declarations used "const uschar *" and the
definitions used USPTR. Even though USPTR is normally defined as "const
unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
reported that: "This difference in casting confuses some C++ compilers, for
example, SunCC recognizes above declarations as different functions and
generates broken code for hbpcre." I have changed the declarations to use
16. GNU libtool is named differently on some systems. The script now
tries several variants such as glibtoolize (MacOSX) and libtoolize1x
17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
(strtoXX undefined when compiling The patch contains this
comment: "Figure out how to create a longlong from a string: strtoll and
equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
instance, but it only takes 2 args instead of 3!"
18. A subtle bug concerned with back references has been fixed by a change of
specification, with a corresponding code fix. A pattern such as
^(xa|=?\1a)+$ which contains a back reference inside the group to which it
refers, was giving matches when it shouldn't. For example, xa=xaaa would
match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
same bug. Such groups have to be quantified to be useful, or contained
inside another quantified group. (If there's no repetition, the reference
can never match.) The problem arises because, having left the group and
moved on to the rest of the pattern, a later failure that backtracks into
the group uses the captured value from the final iteration of the group
rather than the correct earlier one. I have fixed this in PCRE by forcing
any group that contains a reference to itself to be an atomic group; that
is, there cannot be any backtracking into it once it has completed. This is
similar to recursive and subroutine calls.
Version 8.00 19-Oct-09
1. The table for translating pcre_compile() error codes into POSIX error codes
was out-of-date, and there was no check on the pcre_compile() error code
being within the table. This could lead to an OK return being given in
2. Changed the call to open a subject file in pcregrep from fopen(pathname,
"r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
in a Windows environment.
3. The pcregrep --count option prints the count for each file even when it is
zero, as does GNU grep. However, pcregrep was also printing all files when
--files-with-matches was added. Now, when both options are given, it prints
counts only for those files that have at least one match. (GNU grep just
prints the file name in this circumstance, but including the count seems
more useful - otherwise, why use --count?) Also ensured that the
combination -clh just lists non-zero counts, with no names.
4. The long form of the pcregrep -F option was incorrectly implemented as
--fixed_strings instead of --fixed-strings. This is an incompatible change,
but it seems right to fix it, and I didn't think it was worth preserving
the old behaviour.
5. The command line items --regex=pattern and --regexp=pattern were not
recognized by pcregrep, which required --regex pattern or --regexp pattern
(with a space rather than an '='). The man page documented the '=' forms,
which are compatible with GNU grep; these now work.
6. No libpcreposix.pc file was created for pkg-config; there was just
libpcre.pc and libpcrecpp.pc. The omission has been rectified.
7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
when UCP support is not needed, by modifying the Python script that
generates it from Unicode data files. This should not matter if the module
is correctly used as a library, but I received one complaint about 50K of
unwanted data. My guess is that the person linked everything into his
program rather than using a library. Anyway, it does no harm.
8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
was a minimum greater than 1 for a wide character in a possessive
repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
which had an unlimited repeat of a nested, fixed maximum repeat of a wide
character. Chaos in the form of incorrect output or a compiling loop could
9. The restrictions on what a pattern can contain when partial matching is
requested for pcre_exec() have been removed. All patterns can now be
partially matched by this function. In addition, if there are at least two
slots in the offset vector, the offset of the earliest inspected character
for the match and the offset of the end of the subject are set in them when
10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
synonymous with PCRE_PARTIAL, for backwards compatibility, and
PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
and may be more useful for multi-segment matching.
11. Partial matching with pcre_exec() is now more intuitive. A partial match
used to be given if ever the end of the subject was reached; now it is
given only if matching could not proceed because another character was
needed. This makes a difference in some odd cases such as Z(*FAIL) with the
string "Z", which now yields "no match" instead of "partial match". In the
case of pcre_dfa_exec(), "no match" is given if every matching path for the
final character ended with (*FAIL).
12. Restarting a match using pcre_dfa_exec() after a partial match did not work
if the pattern had a "must contain" character that was already found in the
earlier partial match, unless partial matching was again requested. For
example, with the pattern /dog.(body)?/, the "must contain" character is
"g". If the first part-match was for the string "dog", restarting with
"sbody" failed. This bug has been fixed.
13. The string returned by pcre_dfa_exec() after a partial match has been
changed so that it starts at the first inspected character rather than the
first character of the match. This makes a difference only if the pattern
starts with a lookbehind assertion or \b or \B (\K is not supported by
pcre_dfa_exec()). It's an incompatible change, but it makes the two
matching functions compatible, and I think it's the right thing to do.
14. Added a pcredemo man page, created automatically from the pcredemo.c file,
so that the demonstration program is easily available in environments where
PCRE has not been installed from source.
15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
is not the first non-POSIX option to be added. Clearly some people find
these options useful.
17. If a caller to the POSIX matching function regexec() passes a non-zero
value for nmatch with a NULL value for pmatch, the value of
nmatch is forced to zero.
18. RunGrepTest did not have a test for the availability of the -u option of
the diff command, as RunTest does. It now checks in the same way as
RunTest, and also checks for the -b option.
19. If an odd number of negated classes containing just a single character
interposed, within parentheses, between a forward reference to a named
subpattern and the definition of the subpattern, compilation crashed with
an internal error, complaining that it could not find the referenced
subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
[The bug was that it was starting one character too far in when skipping
over the character class, thus treating the ] as data rather than
terminating the class. This meant it could skip too much.]
20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
/g option in pcretest when the pattern contains \K, which makes it possible
to have an empty string match not at the start, even when the pattern is
anchored. Updated pcretest and pcredemo to use this option.
21. If the maximum number of capturing subpatterns in a recursion was greater
than the maximum at the outer level, the higher number was returned, but
with unset values at the outer level. The correct (outer level) value is
now given.
22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
PCRE did not set those parentheses (unlike Perl). I have now found a way to
make it do so. The string so far is captured, making this feature
compatible with Perl.
23. The tests have been re-organized, adding tests 11 and 12, to make it
possible to check the Perl 5.10 features against Perl 5.10.
24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
pattern matches a fixed length string. PCRE did not allow this; now it
does. Neither allows recursion.
25. I finally figured out how to implement a request to provide the minimum
length of subject string that was needed in order to match a given pattern.
(It was back references and recursion that I had previously got hung up
on.) This code has now been added to pcre_study(); it finds a lower bound
to the length of subject needed. It is not necessarily the greatest lower
bound, but using it to avoid searching strings that are too short does give
some useful speed-ups. The value is available to calling programs via
26. While implementing 25, I discovered to my embarrassment that pcretest had
not been passing the result of pcre_study() to pcre_dfa_exec(), so the
study optimizations had never been tested with that matching function.
Oops. What is worse, even when it was passed study data, there was a bug in
pcre_dfa_exec() that meant it never actually used it. Double oops. There
were also very few tests of studied patterns with pcre_dfa_exec().
27. If (?| is used to create subpatterns with duplicate numbers, they are now
allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
on the other side of the coin, they are no longer allowed to have different
names, because these cannot be distinguished in PCRE, and this has caused
confusion. (This is a difference from Perl.)
28. When duplicate subpattern names are present (necessarily with different
numbers, as required by 27 above), and a test is made by name in a
conditional pattern, either for a subpattern having been matched, or for
recursion in such a pattern, all the associated numbered subpatterns are
tested, and the overall condition is true if the condition is true for any
one of them. This is the way Perl works, and is also more like the way
testing by number works.
Version 7.9 11-Apr-09
1. When building with support for bzlib/zlib (pcregrep) and/or readline
(pcretest), all targets were linked against these libraries. This included
libpcre, libpcreposix, and libpcrecpp, even though they do not use these
libraries. This caused unwanted dependencies to be created. This problem
has been fixed, and now only pcregrep is linked with bzlib/zlib and only
pcretest is linked with readline.
2. The "typedef int BOOL" in pcre_internal.h that was included inside the
"#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
moved outside it again, because FALSE and TRUE are already defined in AIX,
but BOOL is not.
3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
4. The pcregrep documentation said spaces were inserted as well as colons (or
hyphens) following file names and line numbers when outputting matching
lines. This is not true; no spaces are inserted. I have also clarified the
wording for the --colour (or --color) option.
5. In pcregrep, when --colour was used with -o, the list of matching strings
was not coloured; this is different to GNU grep, so I have changed it to be
the same.
6. When --colo(u)r was used in pcregrep, only the first matching substring in
each matching line was coloured. Now it goes on to look for further matches
of any of the test patterns, which is the same behaviour as GNU grep.
7. A pattern that could match an empty string could cause pcregrep to loop; it
doesn't make sense to accept an empty string match in pcregrep, so I have
locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
seems to be how GNU grep behaves.
8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
start or after a newline", because the conditional assertion was not being
correctly handled. The rule now is that both the assertion and what follows
in the first alternative must satisfy the test.
9. If auto-callout was enabled in a pattern with a conditional group whose
condition was an assertion, PCRE could crash during matching, both with
pcre_exec() and pcre_dfa_exec().
10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
used for matching.
11. Unicode property support in character classes was not working for
characters (bytes) greater than 127 when not in UTF-8 mode.
12. Added the -M command line option to pcretest.
14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
15. Added the PCRE_NO_START_OPTIMIZE match-time option.
16. Added comments and documentation about mis-use of no_arg in the C++
17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
from Martin Jerabek that uses macro names for all relevant character and
string constants.
18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
these, but not everybody uses configure.
19. A conditional group that had only one branch was not being correctly
recognized as an item that could match an empty string. This meant that an
enclosing group might also not be so recognized, causing infinite looping
(and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
with the subject "ab", where knowledge that the repeated group can match
nothing is needed in order to break the loop.
20. If a pattern that was compiled with callouts was matched using pcre_dfa_
exec(), but without supplying a callout function, matching went wrong.
21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
leak if the size of the offset vector was greater than 30. When the vector
is smaller, the saved offsets during recursion go onto a local stack
vector, but for larger vectors malloc() is used. It was failing to free
when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
error, in fact).
22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
heapframe that is used only when UTF-8 support is enabled. This caused no
problem, but was untidy.
23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
included within another project.
24. Steven Van Ingelgem's patches to add more options to the CMake support,
slightly modified by me:
(a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
not building pcregrep.
(b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
25. Forward references, both numeric and by name, in patterns that made use of
duplicate group numbers, could behave incorrectly or give incorrect errors,
because when scanning forward to find the reference group, PCRE was not
taking into account the duplicate group numbers. A pattern such as
^X(?3)(a)(?|(b)|(q))(Y) is an example.
26. Changed a few more instances of "const unsigned char *" to USPTR, making
the feature of a custom pointer more persuasive (as requested by a user).
27. Wrapped the definitions of fileno and isatty for Windows, which appear in
pcretest.c, inside #ifndefs, because it seems they are sometimes already
28. Added support for (*UTF8) at the start of a pattern.
29. Arrange for flags added by the "release type" setting in CMake to be shown
in the configuration summary.
Version 7.8 05-Sep-08
1. Replaced UCP searching code with optimized version as implemented for Ad
Muncher ( by Peter Kankowski. This uses a two-
stage table and inline lookup instead of a function, giving speed ups of 2
to 5 times on some simple patterns that I tested. Permission was given to
distribute the script that generates the tables (it's not in
the tarball, but is in the Subversion repository).
2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
a group with a zero qualifier. The result of the study could be incorrect,
or the function might crash, depending on the pattern.
4. Caseless matching was not working for non-ASCII characters in back
references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
It now works when Unicode Property Support is available.
5. In pcretest, an escape such as \x{de} in the data was always generating
a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
non-UTF-8 mode. If the value is greater than 255, it gives a warning about
6. Minor bugfix in (change "" == ... to NULL == ...).
7. Added two (int) casts to pcregrep when printing the difference of two
pointers, in case they are 64-bit values.
8. Added comments about Mac OS X stack usage to the pcrestack man page and to
test 2 if it fails.
9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
and a #define of that name to empty if it is not externally set. This is to
allow users of MSVC to set it if necessary.
10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
the convenience functions in the pcre_get.c source file.
11. An option change at the start of a pattern that had top-level alternatives
could cause overwriting and/or a crash. This command provoked a crash in
some environments:
printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
This potential security problem was recorded as CVE-2008-2371.
12. For a pattern where the match had to start at the beginning or immediately
after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
pcre_dfa_exec() could read past the end of the passed subject if there was
no match. To help with detecting such bugs (e.g. with valgrind), I modified
pcretest so that it places the subject at the end of its malloc-ed buffer.
13. The change to pcretest in 12 above threw up a couple more cases when pcre_
exec() might read past the end of the data buffer in UTF-8 mode.
14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
the data contained the byte 0x85 as part of a UTF-8 character within its
first line. This applied both to normal and DFA matching.
15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
/^[^d]*?$/8 failed to match "abc".
16. Added a missing copyright notice to pcrecpp_internal.h.
17. Make it more clear in the documentation that values returned from
pcre_exec() in ovector are byte offsets, not character counts.
18. Tidied a few places to stop certain compilers from issuing warnings.
19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
supplied by Stefan Weber. I made a further small update for 7.8 because
there is a change of source arrangements: the pcre_searchfuncs.c module is
replaced by pcre_ucd.c.
Version 7.7 07-May-08
1. Applied Craig's patch to sort out a long long problem: "If we can't convert
a string to a long long, pretend we don't even have a long long." This is
done by checking for the strtoq, strtoll, and _strtoi64 functions.
2. Applied Craig's patch to to restore ABI compatibility with
pre-7.6 versions, which defined a global no_arg variable instead of putting
it in the RE class. (See also #8 below.)
3. Remove a line of dead code, identified by coverity and reported by Nuno
4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
(1) The include/exclude patterns were being applied to the whole pathnames
of files, instead of just to the final components.
(2) If there was more than one level of directory, the subdirectories were
skipped unless they satisfied the include/exclude conditions. This is
inconsistent with GNU grep (and could even be seen as contrary to the
pcregrep specification - which I improved to make it absolutely clear).
The action now is always to scan all levels of directory, and just
apply the include/exclude patterns to regular files.
5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
--exclude_dir in the tests to avoid scanning .svn directories.
6. Applied Craig's patch to the QuoteMeta function so that it escapes the
NUL character as backslash + 0 rather than backslash + NUL, because PCRE
doesn't support NULs in patterns.
7. Added some missing "const"s to declarations of static tables in
pcre_compile.c and pcre_dfa_exec.c.
8. Applied Craig's patch to to fix a problem in OS X that was
caused by fix #2 above. (Subsequently also a second patch to fix the
first patch. And a third patch - this was a messy problem.)
9. Applied Craig's patch to remove the use of push_back().
10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
matching function regexec().
11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
which, however, unlike Perl's \g{...}, are subroutine calls, not back
references. PCRE supports relative numbers with this syntax (I don't think
Oniguruma does).
12. Previously, a group with a zero repeat such as (...){0} was completely
omitted from the compiled regex. However, this means that if the group
was called as a subroutine from elsewhere in the pattern, things went wrong
(an internal error was given). Such groups are now left in the compiled
pattern, with a new opcode that causes them to be skipped at execution
13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
to the way PCRE behaves:
(a) A lone ] character is dis-allowed (Perl treats it as data).
(b) A back reference to an unmatched subpattern matches an empty string
(Perl fails the current match path).
(c) A data ] in a character class must be notated as \] because if the
first data character in a class is ], it defines an empty class. (In
Perl it is not possible to have an empty class.) The empty class []
never matches; it forces failure and is equivalent to (*FAIL) or (?!).
The negative empty class [^] matches any one character, independently
of the DOTALL setting.
14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
non-existent subpattern following a character class starting with ']' and
containing () gave an internal compiling error instead of "reference to
non-existent subpattern". Fortunately, when the pattern did exist, the
compiled code was correct. (When scanning forwards to check for the
existencd of the subpattern, it was treating the data ']' as terminating
the class, so got the count wrong. When actually compiling, the reference
was subsequently set up correctly.)
15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
it was being rejected as not supported by pcre_dfa_exec(), even though
other assertions are supported. I have made pcre_dfa_exec() support
16. The implementation of 13c above involved the invention of a new opcode,
OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
cannot be changed at match time, I realized I could make a small
improvement to matching performance by compiling OP_ALLANY instead of
OP_ANY for "." when DOTALL was set, and then removing the runtime tests
on the OP_ANY path.
17. Compiling pcretest on Windows with readline support failed without the
following two fixes: (1) Make the unistd.h include conditional on
HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
ncurses library to be included for pcretest when ReadLine support is
requested, but also to allow for it to be overridden. This patch came from
Daniel Bergström.
19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
any errors with the current Unicode tables. Thanks to Peter Kankowski for
spotting this.
Version 7.6 28-Jan-08
1. A character class containing a very large number of characters with
codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
2. Patch to cut out the "long long" test in pcrecpp_unittest when
HAVE_LONG_LONG is not defined.
3. Applied Christian Ehrlicher's patch to update the CMake build files to
bring them up to date and include new features. This patch includes:
- Fixed PH's badly added libz and libbz2 support.
- Fixed a problem with static linking.
- Added pcredemo. [But later removed - see 7 below.]
- Fixed dftables problem and added an option.
- Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
- Added readline support for pcretest.
- Added an listing of the option settings after cmake has run.
4. A user submitted a patch to Makefile that makes it easy to create
"pcre.dll" under mingw when using Configure/Make. I added stuff to that cause it to include this special target, without
affecting anything else. Note that the same mingw target plus all
the other distribution libraries and programs are now supported
when configuring with CMake (see 6 below) instead of with
5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
This is an attempt to solve the reported problem "pcrecpp::no_arg is not
exported in the Windows port". It has not yet been confirmed that the patch
solves the problem, but it does no harm.
6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
with CMake, and also correct the comment about stack recursion.
7. Remove the automatic building of pcredemo from the ./configure system and
from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
of a program that users should build themselves after PCRE is installed, so
building it automatically is not really right. What is more, it gave
trouble in some build environments.
8. Further tidies to CMakeLists.txt from Sheri and Christian.
Version 7.5 10-Jan-08
1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
values in parens when parsing an RE using the C++ wrapper."
2. Negative specials like \S did not work in character classes in UTF-8 mode.
Characters greater than 255 were excluded from the class instead of being
3. The same bug as (2) above applied to negated POSIX classes such as
4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
defined or documented. It seems to have been a typo for PCRE_STATIC, so
I have changed it.
5. The construct (?&) was not diagnosed as a syntax error (it referenced the
first named subpattern) and a construct such as (?&a) would reference the
first named subpattern whose name started with "a" (in other words, the
length check was missing). Both these problems are fixed. "Subpattern name
expected" is now given for (?&) (a zero-length name), and this patch also
makes it give the same error for \k'' (previously it complained that that
was a reference to a non-existent subpattern).
6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
this is right because (?- can be followed by option settings as well as by
digits. I have, however, made the messages clearer.
7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
than the number used in the conditional) now cause a compile-time error.
This is actually not compatible with Perl, which accepts such patterns, but
treats the conditional as always being FALSE (as PCRE used to), but it
seems to me that giving a diagnostic is better.
8. Change "alphameric" to the more common word "alphanumeric" in comments
and messages.
9. Fix two occurrences of "backslash" in comments that should have been
10. Remove two redundant lines of code that can never be obeyed (their function
was moved elsewhere).
11. The program that makes PCRE's Unicode character property table had a bug
which caused it to generate incorrect table entries for sequences of
characters that have the same character type, but are in different scripts.
It amalgamated them into a single range, with the script of the first of
them. In other words, some characters were in the wrong script. There were
thirteen such cases, affecting characters in the following ranges:
U+002b0 - U+002c1
U+0060c - U+0060d
U+0061e - U+00612
U+0064b - U+0065e
U+0074d - U+0076d
U+01800 - U+01805
U+01d00 - U+01d77
U+01d9b - U+01dbf
U+0200b - U+0200f
U+030fc - U+030fe
U+03260 - U+0327f
U+0fb46 - U+0fbb1
U+10450 - U+1049d
12. The -o option (show only the matching part of a line) for pcregrep was not
compatible with GNU grep in that, if there was more than one match in a
line, it showed only the first of them. It now behaves in the same way as
GNU grep.
13. If the -o and -v options were combined for pcregrep, it printed a blank
line for every non-matching line. GNU grep prints nothing, and pcregrep now
does the same. The return code can be used to tell if there were any
non-matching lines.
14. Added --file-offsets and --line-offsets to pcregrep.
15. The pattern (?=something)(?R) was not being diagnosed as a potentially
infinitely looping recursion. The bug was that positive lookaheads were not
being skipped when checking for a possible empty match (negative lookaheads
and both kinds of lookbehind were skipped).
16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
inclusion of <windows.h> to before rather than after the definition of
INVALID_FILE_ATTRIBUTES (patch from David Byron).
17. Specifying a possessive quantifier with a specific limit for a Unicode
character property caused pcre_compile() to compile bad code, which led at
runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
caused the error; without that there was no problem.
18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
19. Added --enable-pcretest-libreadline.
20. In, the variable 'count' was incremented twice in
RE::GlobalReplace(). As a result, the number of replacements returned was
double what it should be. I removed one of the increments, but Craig sent a
later patch that removed the other one (the right fix) and added unit tests
that check the return values (which was not done before).
21. Several CMake things:
(1) Arranged that, when cmake is used on Unix, the libraries end up with
the names libpcre and libpcreposix, not just pcre and pcreposix.
(2) The above change means that pcretest and pcregrep are now correctly
linked with the newly-built libraries, not previously installed ones.
22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
UTF-8 newline character). The key issue is that the pattern starts .*;
this means that the match must be either at the beginning, or after a
newline. The bug was in the code for advancing after a failed match and
checking that the new position followed a newline. It was not taking
account of UTF-8 characters correctly.
23. PCRE was behaving differently from Perl in the way it recognized POSIX
character classes. PCRE was not treating the sequence [:...:] as a
character class unless the ... were all letters. Perl, however, seems to
allow any characters between [: and :], though of course it rejects as
unknown any "names" that contain non-letters, because all the known class
names consist only of letters. Thus, Perl gives an error for [[:1234:]],
for example, whereas PCRE did not - it did not recognize a POSIX character
class. This seemed a bit dangerous, so the code has been changed to be
closer to Perl. The behaviour is not identical to Perl, because PCRE will
diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
Perl does, and where it didn't before.
24. Rewrite so as to remove the single use of %n from pcregrep because in some
Windows environments %n is disabled by default.
Version 7.4 21-Sep-07
1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
means that a class such as [\s] counted as "explicit reference to CR or
LF". That isn't really right - the whole point of the change was to try to
help when there was an actual mention of one of the two characters. So now
the change happens only if \r or \n (or a literal CR or LF) character is
2. The 32-bit options word was also used for 6 internal flags, but the numbers
of both had grown to the point where there were only 3 bits left.
Fortunately, there was spare space in the data structure, and so I have
moved the internal flags into a new 16-bit field to free up more option
3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
but did not set the internal JCHANGED flag - either of these is enough to
control the way the "get" function works - but the PCRE_INFO_JCHANGED
facility is supposed to tell if (?J) was ever used, so now (?J) at the
start sets both bits.
4. Added options (at build time, compile time, exec time) to change \R from
matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
5. doc/pcresyntax.html was missing from the distribution.
6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
compatibility, even though it is no longer used.
7. Added macro for snprintf to and also for strtoll and
strtoull to to select the available functions in WIN32 when the
windows.h file is present (where different names are used). [This was
reversed later after testing - see 16 below.]
8. Changed all #include <config.h> to #include "config.h". There were also
some further <pcre.h> cases that I changed to "pcre.h".
9. When pcregrep was used with the --colour option, it missed the line ending
sequence off the lines that it output.
10. It was pointed out to me that arrays of string pointers cause lots of
relocations when a shared library is dynamically loaded. A technique of
using a single long string with a table of offsets can drastically reduce
these. I have refactored PCRE in four places to do this. The result is
Originally: 290
After changing UCP table: 187
After changing error message table: 43
After changing table of "verbs" 36
After changing table of Posix names 22
Thanks to the folks working on Gregex for glib for this insight.
11. --disable-stack-for-recursion caused compiling to fail unless -enable-
unicode-properties was also set.
12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
13. Added checks for ANY and ANYCRLF to where it previously
checked only for CRLF.
14. Added casts to pcretest.c to avoid compiler warnings.
15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
entirely. This removes changes made in 7 above.
17. The CMake files have been updated, and there is now more information about
building with CMake in the NON-UNIX-USE document.
Version 7.3 28-Aug-07
1. In the rejigging of the build system that eventually resulted in 7.1, the
line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
brackets there is not right, since it causes compilers to look for an
installed pcre.h, not the version that is in the source that is being
compiled (which of course may be different). I have changed it back to:
#include "pcre.h"
I have a vague recollection that the change was concerned with compiling in
different directories, but in the new build system, that is taken care of
by the VPATH setting the Makefile.
2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
when the subject happened to end in the byte 0x85 (e.g. if the last
character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
characters but of course it shouldn't be taken as a newline when it is part
of another character. The bug was that, for an unlimited repeat of . in
not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
characters when looking for a newline.
3. A small performance improvement in the DOTALL UTF-8 mode .* case.
4. Debugging: adjusted the names of opcodes for different kinds of parentheses
in debug output.
5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
long printing in the pcrecpp unittest when running under MinGW.
6. ESC_K was left out of the EBCDIC table.
7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
parentheses; I made it 1000, which seemed large enough. Unfortunately, the
limit also applies to "virtual nesting" when a pattern is recursive, and in
this case 1000 isn't so big. I have been able to remove this limit at the
expense of backing off one optimization in certain circumstances. Normally,
when pcre_exec() would call its internal match() function recursively and
immediately return the result unconditionally, it uses a "tail recursion"
feature to save stack. However, when a subpattern that can match an empty
string has an unlimited repetition quantifier, it no longer makes this
optimization. That gives it a stack frame in which to save the data for
checking that an empty string has been matched. Previously this was taken
from the 1000-entry workspace that had been reserved. So now there is no
explicit limit, but more stack is used.
8. Applied Daniel's patches to solve problems with the import/export magic
syntax that is required for Windows, and which was going wrong for the
pcreposix and pcrecpp parts of the library. These were overlooked when this
problem was solved for the main library.
9. There were some crude static tests to avoid integer overflow when computing
the size of patterns that contain repeated groups with explicit upper
limits. As the maximum quantifier is 65535, the maximum group length was
set at 30,000 so that the product of these two numbers did not overflow a
32-bit integer. However, it turns out that people want to use groups that
are longer than 30,000 bytes (though not repeat them that many times).
Change 7.0/17 (the refactoring of the way the pattern size is computed) has
made it possible to implement the integer overflow checks in a much more
dynamic way, which I have now done. The artificial limitation on group
length has been removed - we now have only the limit on the total length of
the compiled pattern, which depends on the LINK_SIZE setting.
10. Fixed a bug in the documentation for get/copy named substring when
duplicate names are permitted. If none of the named substrings are set, the
functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
empty string.
11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
because the ] is interpreted as the first data character and the
terminating ] is not found. PCRE has been made compatible with Perl in this
regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
cause memory overwriting.
10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
string has been matched (to stop an infinite loop). It was not recognizing
a conditional subpattern that could match an empty string if that
subpattern was within another subpattern. For example, it looped when
trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
condition was not nested. This bug has been fixed.
12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
past the start of the subject in the presence of bytes with the top bit
set, for example "\x8aBCD".
13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
(*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
14. Optimized (?!) to (*FAIL).
15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
This restricts code points to be within the range 0 to 0x10FFFF, excluding
the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
does: it's just the validity check that is more restrictive.
16. Inserted checks for integer overflows during escape sequence (backslash)
processing, and also fixed erroneous offset values for syntax errors during
backslash processing.
17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
caused an overrun.
19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
something other than just ASCII characters) inside a group that had an
unlimited repeat caused a loop at compile time (while checking to see
whether the group could match an empty string).
20. Debugging a pattern containing \p or \P could cause a crash. For example,
[\P{Any}] did so. (Error in the code for printing property names.)
21. An orphan \E inside a character class could cause a crash.
22. A repeated capturing bracket such as (A)? could cause a wild memory
reference during compilation.
23. There are several functions in pcre_compile() that scan along a compiled
expression for various reasons (e.g. to see if it's fixed length for look
behind). There were bugs in these functions when a repeated \p or \P was
present in the pattern. These operators have additional parameters compared
with \d, etc, and these were not being taken into account when moving along
the compiled data. Specifically:
(a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
(b) An item such as \pL+ within a repeated group could cause crashes or
(c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
"reference to non-existent subpattern" error.
(d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
character were causing crashes (broken optimization).
27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
\p or \P) caused a compile-time loop.
28. More problems have arisen in unanchored patterns when CRLF is a valid line
break. For example, the unstudied pattern [\r\n]A does not match the string
"\r\nA" because change 7.0/46 below moves the current point on by two
characters after failing to match at the start. However, the pattern \nA
*does* match, because it doesn't start till \n, and if [\r\n]A is studied,
the same is true. There doesn't seem any very clean way out of this, but
what I have chosen to do makes the common cases work: PCRE now takes note
of whether there can be an explicit match for \r or \n anywhere in the
pattern, and if so, 7.0/46 no longer applies. As part of this change,
there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
pattern has explicit CR or LF references.
29. Added (*CR) etc for changing newline setting at start of pattern.
Version 7.2 19-Jun-07
1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
which is apparently normally available under Windows.
2. Re-jig the pcregrep tests with different newline settings in an attempt
to make them independent of the local environment's newline setting.
3. Add code to to remove -g from the CFLAGS default settings.
4. Some of the "internals" tests were previously cut out when the link size
was not 2, because the output contained actual offsets. The recent new
"Z" feature of pcretest means that these can be cut out, making the tests
usable with all link sizes.
5. Implemented Stan Switzer's goto replacement for longjmp() when not using
stack recursion. This gives a massive performance boost under BSD, but just
a small improvement under Linux. However, it saves one field in the frame
in all cases.
6. Added more features from the forthcoming Perl 5.10:
(a) (?-n) (where n is a string of digits) is a relative subroutine or
recursion call. It refers to the nth most recently opened parentheses.
(b) (?+n) is also a relative subroutine call; it refers to the nth next
to be opened parentheses.
(c) Conditions that refer to capturing parentheses can be specified
relatively, for example, (?(-2)... or (?(+3)...
(d) \K resets the start of the current match so that everything before
is not part of it.
(e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
(f) \g{name} is another synonym - part of Perl 5.10's unification of
reference syntax.
(g) (?| introduces a group in which the numbering of parentheses in each
alternative starts with the same number.
(h) \h, \H, \v, and \V match horizontal and vertical whitespace.
7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
for detecting groups that can match an empty string.
9. A pattern with a very large number of alternatives (more than several
hundred) was running out of internal workspace during the pre-compile
phase, where pcre_compile() figures out how much memory will be needed. A
bit of new cunning has reduced the workspace needed for groups with
alternatives. The 1000-alternative test pattern now uses 12 bytes of
workspace instead of running out of the 4096 that are available.
10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
11. Applied patch from Google to remove an optimization that didn't quite work.
The report of the bug said:
pcrecpp::RE("a*").FullMatch("aaa") matches, while
pcrecpp::RE("a*?").FullMatch("aaa") does not, and
pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
it matched the wrong number of bytes.
Version 7.1 24-Apr-07
1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
that is more "standard", making use of automake and other Autotools. There
is some re-arrangement of the files and adjustment of comments consequent
on this.
2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
for recursive directory scanning broke on some systems because the files
are not scanned in any specific order and on different systems the order
was different. A call to "sort" has been inserted into RunGrepTest for the
approprate test as a short-term fix. In the longer term there may be an
3. I had an email from Eric Raymond about problems translating some of PCRE's
man pages to HTML (despite the fact that I distribute HTML pages, some
people do their own conversions for various reasons). The problems
concerned the use of low-level troff macros .br and .in. I have therefore
removed all such uses from the man pages (some were redundant, some could
be replaced by .nf/.fi pairs). The 132html script that I use to generate
HTML has been updated to handle .nf/.fi and to complain if it encounters
.br or .in.
4. Updated comments in that get placed in and also
arranged for config.h to be included in the distribution, with the name
config.h.generic, for the benefit of those who have to compile without
Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
Weber: (1) pcre_internal.h was missing some function renames; (2) updated
makevp.bat for the current PCRE, using the additional files
makevp_c.txt, makevp_l.txt, and pcregexp.pas.
6. A Windows user reported a minor discrepancy with test 2, which turned out
to be caused by a trailing space on an input line that had got lost in his
copy. The trailing space was an accident, so I've just removed it.
7. Add -Wl,-R... flags in for *BSD* systems, as I'm told
that is needed.
8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
as "const" (a) because they are and (b) because it helps the PHP
maintainers who have recently made a script to detect big data structures
in the php code that should be moved to the .rodata section. I remembered
to update Builducptable as well, so it won't revert if ucptable.h is ever
9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
order to be able to cut out the UTF-8 tables in the latter when UTF-8
support is not required. This saves 1.5-2K of code, which is important in
some applications.
Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
so as not to refer to the tables, even though these functions will never be
called when UTF-8 support is disabled. Otherwise there are problems with a
shared library.
10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
(a) It was defining its arguments as char * instead of void *.
(b) It was assuming that all moves were upwards in memory; this was true
a long time ago when I wrote it, but is no longer the case.
The emulated memove() is provided for those environments that have neither
memmove() nor bcopy(). I didn't think anyone used it these days, but that
is clearly not the case, as these two bugs were recently reported.
11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
and Detrail to create the HTML documentation, the .txt form of the man
pages, and it removes trailing spaces from listed files. It also creates
pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
case, it wraps all the #defines with #ifndefs. This script should be run
before "make dist".
12. Fixed two fairly obscure bugs concerned with quantified caseless matching
with Unicode property support.
(a) For a maximizing quantifier, if the two different cases of the
character were of different lengths in their UTF-8 codings (there are
some cases like this - I found 11), and the matching function had to
back up over a mixture of the two cases, it incorrectly assumed they
were both the same length.
(b) When PCRE was configured to use the heap rather than the stack for
recursion during matching, it was not correctly preserving the data for
the other case of a UTF-8 character when checking ahead for a match
while processing a minimizing repeat. If the check also involved
matching a wide character, but failed, corruption could cause an
erroneous result when trying to check for a repeat of the original
13. Some tidying changes to the testing mechanism:
(a) The RunTest script now detects the internal link size and whether there
is UTF-8 and UCP support by running ./pcretest -C instead of relying on
values substituted by "configure". (The RunGrepTest script already did
this for UTF-8.) The script no longer substitutes the
relevant variables.
(b) The debugging options /B and /D in pcretest show the compiled bytecode
with length and offset values. This means that the output is different
for different internal link sizes. Test 2 is skipped for link sizes
other than 2 because of this, bypassing the problem. Unfortunately,
there was also a test in test 3 (the locale tests) that used /B and
failed for link sizes other than 2. Rather than cut the whole test out,
I have added a new /Z option to pcretest that replaces the length and
offset values with spaces. This is now used to make test 3 independent
of link size. (Test 2 will be tidied up later.)
14. If erroroffset was passed as NULL to pcre_compile, it provoked a
segmentation fault instead of returning the appropriate error message.
15. In multiline mode when the newline sequence was set to "any", the pattern
^$ would give a match between the \r and \n of a subject such as "A\r\nB".
This doesn't seem right; it now treats the CRLF combination as the line
ending, and so does not match in that case. It's only a pattern such as ^$
that would hit this one: something like ^ABC$ would have failed after \r
and then tried again after \r\n.
16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
in an attempt to make files that differ only in their line terminators
compare equal. This works on Linux.
17. Under certain error circumstances pcregrep might try to free random memory
as it exited. This is now fixed, thanks to valgrind.
19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
"abc\r\n\r\n", it found an unwanted second match after the second \r. This
was because its rules for how to advance for /g after matching an empty
string at the end of a line did not allow for this case. They now check for
it specially.
20. pcretest is supposed to handle patterns and data of any length, by
extending its buffers when necessary. It was getting this wrong when the
buffer for a data line had to be extended.
21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
CRLF as a newline sequence.
22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
I have nevertheless tidied it up.
23. Added some casts to kill warnings from HP-UX ia64 compiler.
24. Added a man page for pcre-config.
Version 7.0 19-Dec-06
1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
moving to gcc 4.1.1.
2. The -S option for pcretest uses setrlimit(); I had omitted to #include
sys/time.h, which is documented as needed for this function. It doesn't
seem to matter on Linux, but it showed up on some releases of OS X.
3. It seems that there are systems where bytes whose values are greater than
127 match isprint() in the "C" locale. The "C" locale should be the
default when a C program starts up. In most systems, only ASCII printing
characters match isprint(). This difference caused the output from pcretest
to vary, making some of the tests fail. I have changed pcretest so that:
(a) When it is outputting text in the compiled version of a pattern, bytes
other than 32-126 are always shown as hex escapes.
(b) When it is outputting text that is a matched part of a subject string,
it does the same, unless a different locale has been set for the match
(using the /L modifier). In this case, it uses isprint() to decide.
4. Fixed a major bug that caused incorrect computation of the amount of memory
required for a compiled pattern when options that changed within the
pattern affected the logic of the preliminary scan that determines the
length. The relevant options are -x, and -i in UTF-8 mode. The result was
that the computed length was too small. The symptoms of this bug were
either the PCRE error "internal error: code overflow" from pcre_compile(),
or a glibc crash with a message such as "pcretest: free(): invalid next
size (fast)". Examples of patterns that provoked this bug (shown in
pcretest format) are:
/(?-x: )/x
/(?x)(?-x: \s*#\s*)/
HOWEVER: Change 17 below makes this fix obsolete as the memory computation
is now done differently.
5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
wrapper classes; (b) implement a new function in the C++ scanner that is
more efficient than the old way of doing things because it avoids levels of
recursion in the regex matching; (c) add a paragraph to the documentation
for the FullMatch() function.
6. The escape sequence \n was being treated as whatever was defined as
"newline". Not only was this contrary to the documentation, which states
that \n is character 10 (hex 0A), but it also went horribly wrong when
"newline" was defined as CRLF. This has been fixed.
7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
was being set to -1 for the "end of line" case (supposedly a value that no
character can have). Though this value is never used (the check for end of
line is "zero bytes in current character"), it caused compiler complaints.
I've changed it to 0xffffffff.
8. In pcre_version.c, the version string was being built by a sequence of
C macros that, in the event of PCRE_PRERELEASE being defined as an empty
string (as it is for production releases) called a macro with an empty
argument. The C standard says the result of this is undefined. The gcc
compiler treats it as an empty string (which was what was wanted) but it is
reported that Visual C gives an error. The source has been hacked around to
avoid this problem.
9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
builds of pcretest, and changed the call to _setmode() to use _O_BINARY
instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
of them did).
10. Originally, pcretest opened its input and output without "b"; then I was
told that "b" was needed in some environments, so it was added for release
5.0 to both the input and output. (It makes no difference on Unix-like
systems.) Later I was told that it is wrong for the input on Windows. I've
now abstracted the modes into two macros, to make it easier to fiddle with
them, and removed "b" from the input mode under Windows.
11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
12. Added -help and --help to pcretest as an official way of being reminded
of the options.
13. Removed some redundant semicolons after macro calls in
and because they annoy compilers at high warning levels.
14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
15. Fixed an occurrence of == in that should have been = (shell
scripts are not C programs :-) and which was not noticed because it works
on Linux.
16. pcretest is supposed to handle any length of pattern and data line (as one
line or as a continued sequence of lines) by extending its input buffer if
necessary. This feature was broken for very long pattern lines, leading to
a string of junk being passed to pcre_compile() if the pattern was longer
than about 50K.
17. I have done a major re-factoring of the way pcre_compile() computes the
amount of memory needed for a compiled pattern. Previously, there was code
that made a preliminary scan of the pattern in order to do this. That was
OK when PCRE was new, but as the facilities have expanded, it has become
harder and harder to keep it in step with the real compile phase, and there
have been a number of bugs (see for example, 4 above). I have now found a
cunning way of running the real compile function in a "fake" mode that
enables it to compute how much memory it would need, while actually only
ever using a few hundred bytes of working memory and without too many
tests of the mode. This should make future maintenance and development
easier. A side effect of this work is that the limit of 200 on the nesting
depth of parentheses has been removed (though this was never a serious
limitation, I suspect). However, there is a downside: pcre_compile() now
runs more slowly than before (30% or more, depending on the pattern). I
hope this isn't a big issue. There is no effect on runtime performance.
18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
newline (only possible for the last line of a file) and it was a
pattern that set a locale (followed by /Lsomething), pcretest crashed.
19. Added additional timing features to pcretest. (1) The -tm option now times
matching only, not compiling. (2) Both -t and -tm can be followed, as a
separate command line item, by a number that specifies the number of
repeats to use when timing. The default is 50000; this gives better
precision, but takes uncomfortably long for very large patterns.
20. Extended pcre_study() to be more clever in cases where a branch of a
subpattern has no definite first character. For example, (a*|b*)[cd] would
previously give no result from pcre_study(). Now it recognizes that the
first character must be a, b, c, or d.
21. There was an incorrect error "recursive call could loop indefinitely" if
a subpattern (or the entire pattern) that was being tested for matching an
empty string contained only one non-empty item after a nested subpattern.
For example, the pattern (?>\x{100}*)\d(?R) provoked this error
incorrectly, because the \d was being skipped in the check.
22. The pcretest program now has a new pattern option /B and a command line
option -b, which is equivalent to adding /B to every pattern. This causes
it to show the compiled bytecode, without the additional information that
-d shows. The effect of -d is now the same as -b with -i (and similarly, /D
is the same as /B/I).
23. A new optimization is now able automatically to treat some sequences such
as a*b as a*+b. More specifically, if something simple (such as a character
or a simple class like \d) has an unlimited quantifier, and is followed by
something that cannot possibly match the quantified thing, the quantifier
is automatically "possessified".
24. A recursive reference to a subpattern whose number was greater than 39
went wrong under certain circumstances in UTF-8 mode. This bug could also
have affected the operation of pcre_study().
25. Realized that a little bit of performance could be had by replacing
(c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
27. Possessive quantifiers such as a++ were previously implemented by turning
them into atomic groups such as ($>a+). Now they have their own opcodes,
which improves performance. This includes the automatically created ones
from 23 above.
28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
lookahead was broken if it was not anchored. PCRE was mistakenly expecting
the first matched character to be a colon. This applied both to named and
numbered groups.
29. The ucpinternal.h header file was missing its idempotency #ifdef.
30. I was sent a "project" file called which I understand makes
building PCRE on Windows easier, so I have included it in the distribution.
31. There is now a check in pcretest against a ridiculously large number being
returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
loop, the loop is abandoned.
32. Forward references to subpatterns in conditions such as (?(2)...) where
subpattern 2 is defined later cause pcre_compile() to search forwards in
the pattern for the relevant set of parentheses. This search went wrong
when there were unescaped parentheses in a character class, parentheses
escaped with \Q...\E, or parentheses in a #-comment in /x mode.
33. "Subroutine" calls and backreferences were previously restricted to
referencing subpatterns earlier in the regex. This restriction has now
been removed.
34. Added a number of extra features that are going to be in Perl 5.10. On the
whole, these are just syntactic alternatives for features that PCRE had
previously implemented using the Python syntax or my own invention. The
other formats are all retained for compatibility.
(a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
as (?P<name>...). The new forms, as well as being in Perl 5.10, are
also .NET compatible.
(b) A recursion or subroutine call to a named group can now be defined as
(?&name) as well as (?P>name).
(c) A backreference to a named group can now be defined as \k<name> or
\k'name' as well as (?P=name). The new forms, as well as being in Perl
5.10, are also .NET compatible.
(d) A conditional reference to a named group can now use the syntax
(?(<name>) or (?('name') as well as (?(name).
(e) A "conditional group" of the form (?(DEFINE)...) can be used to define
groups (named and numbered) that are never evaluated inline, but can be
called as "subroutines" from elsewhere. In effect, the DEFINE condition
is always false. There may be only one alternative in such a group.
(f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
as the simple (?(R). The condition is true only if the most recent
recursion is that of the given number or name. It does not search out
through the entire recursion stack.
(g) The escape \gN or \g{N} has been added, where N is a positive or
negative number, specifying an absolute or relative reference.
35. Tidied to get rid of some further signed/unsigned compiler warnings and
some "unreachable code" warnings.
36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
things, this adds five new scripts.
37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
There were also incompatibilities regarding the handling of \Q..\E inside
character classes, for example with patterns like [\Qa\E-\Qz\E] where the
hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
matches an empty string, and forcibly breaks the loop. There were bugs in
this code in non-simple cases. For a pattern such as ^(a()*)* matched
against aaaa the result was just "a" rather than "aaaa", for example. Two
separate and independent bugs (that affected different cases) have been
39. Refactored the code to abolish the use of different opcodes for small
capturing bracket numbers. This is a tidy that I avoided doing when I
removed the limit on the number of capturing brackets for 3.5 back in 2001.
The new approach is not only tidier, it makes it possible to reduce the
memory needed to fix the previous bug (38).
40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
sequences ( as "newline" when
processing dot, circumflex, or dollar metacharacters, or #-comments in /x
41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
42. Applied patch, originally from Ari Pollak, modified by Google, to allow
copy construction and assignment in the C++ wrapper.
43. Updated pcregrep to support "--newline=any". In the process, I fixed a
couple of bugs that could have given wrong results in the "--newline=crlf"
44. Added a number of casts and did some reorganization of signed/unsigned int
variables following suggestions from Dair Grant. Also renamed the variable
"this" as "item" because it is a C++ keyword.
45. Arranged for dftables to add
#include "pcre_internal.h"
to pcre_chartables.c because without it, gcc 4.x may remove the array
definition from the final binary if PCRE is built into a static library and
dead code stripping is activated.
46. For an unanchored pattern, if a match attempt fails at the start of a
newline sequence, and the newline setting is CRLF or ANY, and the next two
characters are CRLF, advance by two characters instead of one.
Version 6.7 04-Jul-06
1. In order to handle tests when input lines are enormously long, pcretest has
been re-factored so that it automatically extends its buffers when
necessary. The code is crude, but this _is_ just a test program. The
default size has been increased from 32K to 50K.
2. The code in pcre_study() was using the value of the re argument before
testing it for NULL. (Of course, in any sensible call of the function, it
won't be NULL.)
3. The memmove() emulation function in pcre_internal.h, which is used on
systems that lack both memmove() and bcopy() - that is, hardly ever -
was missing a "static" storage class specifier.
4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
containing an extended class (one that cannot be represented by a bitmap
because it contains high-valued characters or Unicode property items, e.g.
[\pZ]). Almost always one would set UTF-8 mode when processing such a
pattern, but PCRE should not loop if you do not (it no longer does).
[Detail: two cases were found: (a) a repeated subpattern containing an
extended class; (b) a recursive reference to a subpattern that followed a
previous extended class. It wasn't skipping over the extended class
correctly when UTF-8 mode was not set.]
5. A negated single-character class was not being recognized as fixed-length
in lookbehind assertions such as (?<=[^f]), leading to an incorrect
compile error "lookbehind assertion is not fixed length".
6. The RunPerlTest auxiliary script was showing an unexpected difference
between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
write a Perl script that can interpret lines of an input file either as
byte characters or as UTF-8, which is what "perltest" was being required to
do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
can't do is switch easily at run time between having the "use utf8;" pragma
or not. In the end, I fudged it by using the RunPerlTest script to insert
"use utf8;" explicitly for the UTF-8 tests.
7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
the end of the subject string, contrary to the documentation and to what
Perl does. This was true of both matching functions. Now it matches only at
the start of the subject and immediately after *internal* newlines.
8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
a pointer to an int instead of a pointer to an unsigned long int. This
caused problems on 64-bit systems.
9. Applied a patch from the folks at Google to, to fix "another
instance of the 'standard' template library not being so standard".
10. There was no check on the number of named subpatterns nor the maximum
length of a subpattern name. The product of these values is used to compute
the size of the memory block for a compiled pattern. By supplying a very
long subpattern name and a large number of named subpatterns, the size
computation could be caused to overflow. This is now prevented by limiting
the length of names to 32 characters, and the number of named subpatterns
to 10,000.
11. Subpatterns that are repeated with specific counts have to be replicated in
the compiled pattern. The size of memory for this was computed from the
length of the subpattern and the repeat count. The latter is limited to
65535, but there was no limit on the former, meaning that integer overflow
could in principle occur. The compiled length of a repeated subpattern is
now limited to 30,000 bytes in order to prevent this.
12. Added the optional facility to have named substrings with the same name.
13. Added the ability to use a named substring as a condition, using the
Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
are numbers (not recommended). Forward references are permitted.
14. Added forward references in named backreferences (if you see what I mean).
15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
pattern could run off the end of the subject. For example, the pattern
"(?s)(.{1,5})"8 did this with the subject "ab".
16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
PCRE_CASELESS was set when matching characters that were quantified with ?
or *.
17. A character class other than a single negated character that had a minimum
but no maximum quantifier - for example [ab]{6,} - was not handled
correctly by pce_dfa_exec(). It would match only one character.
18. A valid (though odd) pattern that looked like a POSIX character
class but used an invalid character after [ (for example [[,abc,]]) caused
pcre_compile() to give the error "Failed: internal error: code overflow" or
in some cases to crash with a glibc free() error. This could even happen if
the pattern terminated after [[ but there just happened to be a sequence of
letters, a binary zero, and a closing ] in the memory that followed.
19. Perl's treatment of octal escapes in the range \400 to \777 has changed
over the years. Originally (before any Unicode support), just the bottom 8
bits were taken. Thus, for example, \500 really meant \100. Nowadays the
output from "man perlunicode" includes this:
The regular expression compiler produces polymorphic opcodes. That
is, the pattern adapts to the data and automatically switches to
the Unicode character scheme when presented with Unicode data--or
instead uses a traditional byte scheme when presented with byte
Sadly, a wide octal escape does not cause a switch, and in a string with
no other multibyte characters, these octal escapes are treated as before.
Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
/\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
Unicode string.
I have not perpetrated such confusion in PCRE. Up till now, it took just
the bottom 8 bits, as in old Perl. I have now made octal escapes with
values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
translate to the appropriate multibyte character.
29. Applied some refactoring to reduce the number of warnings from Microsoft
and Borland compilers. This has included removing the fudge introduced
seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
a warning about an unused variable.
21. PCRE has not included VT (character 0x0b) in the set of whitespace
characters since release 4.0, because Perl (from release 5.004) does not.
[Or at least, is documented not to: some releases seem to be in conflict
with the documentation.] However, when a pattern was studied with
pcre_study() and all its branches started with \s, PCRE still included VT
as a possible starting character. Of course, this did no harm; it just
caused an unnecessary match attempt.
22. Removed a now-redundant internal flag bit that recorded the fact that case
dependency changed within the pattern. This was once needed for "required
byte" processing, but is no longer used. This recovers a now-scarce options
bit. Also moved the least significant internal flag bit to the most-
significant bit of the word, which was not previously used (hangover from
the days when it was an int rather than a uint) to free up another bit for
the future.
23. Added support for CRLF line endings as well as CR and LF. As well as the
default being selectable at build time, it can now be changed at runtime
via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
specify that it is scanning data with non-default line endings.
24. Changed the definition of CXXLINK to make it agree with the definition of
LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
25. Applied Ian Taylor's patches to avoid using another stack frame for tail
recursions. This makes a big different to stack usage for some patterns.
26. If a subpattern containing a named recursion or subroutine reference such
as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
the space required for the compiled pattern went wrong and gave too small a
value. Depending on the environment, this could lead to "Failed: internal
error: code overflow at offset 49" or "glibc detected double free or
corruption" errors.
27. Applied patches from Google (a) to support the new newline modes and (b) to
advance over multibyte UTF-8 characters in GlobalReplace.
28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
difference for some implementation of PCRE in some Windows version.
29. Added some extra testing facilities to pcretest:
\q<number> in a data line sets the "match limit" value
\Q<number> in a data line sets the "match recursion limt" value
-S <number> sets the stack size, where <number> is in megabytes
The -S option isn't available for Windows.
Version 6.6 06-Feb-06
1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
in pcreposix.h. I have copied the definition from pcre.h.
2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
because pcre.h is no longer a built file.
3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
not normally included in the compiled code.
Version 6.5 01-Feb-06
1. When using the partial match feature with pcre_dfa_exec(), it was not
anchoring the second and subsequent partial matches at the new starting
point. This could lead to incorrect results. For example, with the pattern
/1234/, partially matching against "123" and then "a4" gave a match.
2. Changes to pcregrep:
(a) All non-match returns from pcre_exec() were being treated as failures
to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
error message is output. Some extra information is given for the
probably the only errors that are likely to be caused by users (by
specifying a regex that has nested indefinite repeats, for instance).
If there are more than 20 of these errors, pcregrep is abandoned.
(b) A binary zero was treated as data while matching, but terminated the
output line if it was written out. This has been fixed: binary zeroes
are now no different to any other data bytes.
(c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
used to set a locale for matching. The --locale=xxxx long option has
been added (no short equivalent) to specify a locale explicitly on the
pcregrep command, overriding the environment variables.
(d) When -B was used with -n, some line numbers in the output were one less
than they should have been.
(e) Added the -o (--only-matching) option.
(f) If -A or -C was used with -c (count only), some lines of context were
accidentally printed for the final match.
(g) Added the -H (--with-filename) option.
(h) The combination of options -rh failed to suppress file names for files
that were found from directory arguments.
(i) Added the -D (--devices) and -d (--directories) options.
(j) Added the -F (--fixed-strings) option.
(k) Allow "-" to be used as a file name for -f as well as for a data file.
(l) Added the --colo(u)r option.
(m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
is not present by default.
3. A nasty bug was discovered in the handling of recursive patterns, that is,
items such as (?R) or (?1), when the recursion could match a number of
alternatives. If it matched one of the alternatives, but subsequently,
outside the recursion, there was a failure, the code tried to back up into
the recursion. However, because of the way PCRE is implemented, this is not
possible, and the result was an incorrect result from the match.
In order to prevent this happening, the specification of recursion has
been changed so that all such subpatterns are automatically treated as
atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
4. I had overlooked the fact that, in some locales, there are characters for
which isalpha() is true but neither isupper() nor islower() are true. In
the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
and ordfeminine) are like this. This affected the treatment of \w and \W
when they appeared in character classes, but not when they appeared outside
a character class. The bit map for "word" characters is now created
separately from the results of isalnum() instead of just taking it from the
upper, lower, and digit maps. (Plus the underscore character, of course.)
5. The above bug also affected the handling of POSIX character classes such as
[[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
permanent tables. Instead, the bit maps for such a class were previously
created as the appropriate unions of the upper, lower, and digit bitmaps.
Now they are created by subtraction from the [[:word:]] class, which has
its own bitmap.
6. The [[:blank:]] character class matches horizontal, but not vertical space.
It is created by subtracting the vertical space characters (\x09, \x0a,
\x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
subtraction was done in the overall bitmap for a character class, meaning
that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
be recognized. This bug has been fixed.
7. Patches from the folks at Google:
(a) "to handle a corner case that may or may not happen in
real life, but is still worth protecting against".
(b) "corrects a bug when negative radixes are used with
regular expressions".
(c) avoid use of std::count() because not all systems
have it.
(d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
"configure" and the latter not, in order to fix a problem somebody had
with compiling the Arg class on HP-UX.
(e) Improve the error-handling of the C++ wrapper a little bit.
(f) New tests for checking recursion limiting.
8. The pcre_memmove() function, which is used only if the environment does not
have a standard memmove() function (and is therefore rarely compiled),
contained two bugs: (a) use of int instead of size_t, and (b) it was not
returning a result (though PCRE never actually uses the result).
9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
returned instead of calling malloc() with an overflowing number that would
most likely cause subsequent chaos.
10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
with this option is matched, the nmatch and pmatch options of regexec() are
12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
provided in case anyone wants to the the POSIX interface with UTF-8
13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
C++ linking (needed for some HP-UX environments).
14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
(unused parameter) and in the pcre_printint() function (omitted "default"
switch label when the default is to do nothing).
15. Added some code to make it possible, when PCRE is compiled as a C++
library, to replace subject pointers for pcre_exec() with a smart pointer
class, thus making it possible to process discontinuous strings.
16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
much the same function. They were added by different people who were trying
to make PCRE easy to compile on non-Unix systems. It has been suggested
that PCRE_EXPORT be abolished now that there is more automatic apparatus
for compiling on Windows systems. I have therefore replaced it with
PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
defaults to "extern" for C or "extern C" for C++, which works fine on
Unix-like systems. It is now possible to override the value of PCRE_DATA_
SCOPE with something explicit in config.h. In addition:
(a) pcreposix.h still had just "extern" instead of either of these macros;
I have replaced it with PCRE_DATA_SCOPE.
(b) Functions such as _pcre_xclass(), which are internal to the library,
but external in the C sense, all had PCRE_EXPORT in their definitions.
This is apparently wrong for the Windows case, so I have removed it.
(It makes no difference on Unix-like systems.)
17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
of recursive calls to match(). This is different to MATCH_LIMIT because
that limits the total number of calls to match(), not all of which increase
the depth of recursion. Limiting the recursion depth limits the amount of
stack (or heap if NO_RECURSE is set) that is used. The default can be set
when PCRE is compiled, and changed at run time. A patch from Google adds
this functionality to the C++ interface.
18. Changes to the handling of Unicode character properties:
(a) Updated the table to Unicode 4.1.0.
(b) Recognize characters that are not in the table as "Cn" (undefined).
(c) I revised the way the table is implemented to a much improved format
which includes recognition of ranges. It now supports the ranges that
are defined in UnicodeData.txt, and it also amalgamates other
characters into ranges. This has reduced the number of entries in the
table from around 16,000 to around 3,000, thus reducing its size
considerably. I realized I did not need to use a tree structure after
all - a binary chop search is just as efficient. Having reduced the
number of entries, I extended their size from 6 bytes to 8 bytes to
allow for more data.
(d) Added support for Unicode script names via properties such as \p{Han}.
19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
matching that character.
20. When matching a repeated Unicode property with a minimum greater than zero,
(for example \pL{2,}), PCRE could look past the end of the subject if it
reached it while seeking the minimum number of characters. This could
happen only if some of the characters were more than one byte long, because
there is a check for at least the minimum number of bytes.
21. Refactored the implementation of \p and \P so as to be more general, to
allow for more different types of property in future. This has changed the
compiled form incompatibly. Anybody with saved compiled patterns that use
\p or \P will have to recompile them.
22. Added "Any" and "L&" to the supported property types.
23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
but give a compile time error if the value is greater than 0xff.
24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
accidentally not being installed or uninstalled.
25. The pcre.h file was built from, but the only changes that were
made were to insert the current release number. This seemed silly, because
it made things harder for people building PCRE on systems that don't run
"configure". I have turned pcre.h into a distributed file, no longer built
by "configure", with the version identification directly included. There is
no longer a file.
However, this change necessitated a change to the pcre-config script as
well. It is built from, and one of the substitutions was the
release number. I have updated so that ./configure now finds
the release number by grepping pcre.h.
26. Added the ability to run the tests under valgrind.
Version 6.4 05-Sep-05
1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
"--" to be printed when multiple files were scanned, even when none of the
-A, -B, or -C options were used. This is not compatible with Gnu grep, so I
consider it to be a bug, and have restored the previous behaviour.
2. A couple of code tidies to get rid of compiler warnings.
3. The pcretest program used to cheat by referring to symbols in the library
whose names begin with _pcre_. These are internal symbols that are not
really supposed to be visible externally, and in some environments it is
possible to suppress them. The cheating is now confined to including
certain files from the library's source, which is a bit cleaner.
4. Renamed as to go with; it also makes the
file's purpose clearer.
5. Reorganized pcre_ucp_findchar().
Version 6.3 15-Aug-05
1. The file did not have general read permission in the tarball.
2. There were some problems when building without C++ support:
(a) If C++ support was not built, "make install" and "make test" still
tried to test it.
(b) There were problems when the value of CXX was explicitly set. Some
changes have been made to try to fix these, and ...
(c) --disable-cpp can now be used to explicitly disable C++ support.
(d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
backslash in a target when C++ was disabled. This confuses some
versions of "make", apparently. Using an intermediate variable solves
this. (Same for CPP_LOBJ.)
3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
(non-Windows) now includes $(CFLAGS) because these flags are sometimes
necessary on certain architectures.
4. Added a setting of -export-symbols-regex to the link command to remove
those symbols that are exported in the C sense, but actually are local
within the library, and not documented. Their names all begin with
"_pcre_". This is not a perfect job, because (a) we have to except some
symbols that pcretest ("illegally") uses, and (b) the facility isn't always
available (and never for static libraries). I have made a note to try to
find a way round (a) in the future.
Version 6.2 01-Aug-05
1. There was no test for integer overflow of quantifier values. A construction
such as {1111111111111111} would give undefined results. What is worse, if
a minimum quantifier for a parenthesized subpattern overflowed and became
negative, the calculation of the memory size went wrong. This could have
led to memory overwriting.
2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
operating environments where this matters.
4. Applied Giuseppe Maxia's patch to add additional features for controlling
PCRE options from within the C++ wrapper.
5. Named capturing subpatterns were not being correctly counted when a pattern
was compiled. This caused two problems: (a) If there were more than 100
such subpatterns, the calculation of the memory needed for the whole
compiled pattern went wrong, leading to an overflow error. (b) Numerical
back references of the form \12, where the number was greater than 9, were
not recognized as back references, even though there were sufficient
previous subpatterns.
6. Two minor patches to in order to allow it to compile on older
versions of gcc, e.g. 2.95.4.
Version 6.1 21-Jun-05
1. There was one reference to the variable "posix" in pcretest.c that was not
surrounded by "#if !defined NOPOSIX".
2. Make it possible to compile pcretest without DFA support, UTF8 support, or
the cross-check on the old pcre_info() function, for the benefit of the
cut-down version of PCRE that is currently imported into Exim.
3. A (silly) pattern starting with (?i)(?-i) caused an internal space
allocation error. I've done the easy fix, which wastes 2 bytes for sensible
patterns that start (?i) but I don't think that matters. The use of (?i) is
just an example; this all applies to the other options as well.
4. Since libtool seems to echo the compile commands it is issuing, the output
from "make" can be reduced a bit by putting "@" in front of each libtool
compile command.
5. Patch from the folks at Google for to be a bit more thorough
in checking for a suitable C++ installation before trying to compile the
C++ stuff. This should fix a reported problem when a compiler was present,
but no suitable headers.
6. The man pages all had just "PCRE" as their title. I have changed them to
be the relevant file name. I have also arranged that these names are
retained in the file doc/pcre.txt, which is a concatenation in text format
of all the man pages except the little individual ones for each function.
7. The NON-UNIX-USE file had not been updated for the different set of source
files that come with release 6. I also added a few comments about the C++
Version 6.0 07-Jun-05
1. Some minor internal re-organization to help with my DFA experiments.
2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
didn't matter for the library itself when fully configured, but did matter
when compiling without UCP support, or within Exim, where the ucp files are
not imported.
3. Refactoring of the library code to split up the various functions into
different source modules. The addition of the new DFA matching code (see
below) to a single monolithic source would have made it really too
unwieldy, quite apart from causing all the code to be include in a
statically linked application, when only some functions are used. This is
relevant even without the DFA addition now that patterns can be compiled in
one application and matched in another.
The downside of splitting up is that there have to be some external
functions and data tables that are used internally in different modules of
the library but which are not part of the API. These have all had their
names changed to start with "_pcre_" so that they are unlikely to clash
with other external names.
4. Added an alternate matching function, pcre_dfa_exec(), which matches using
a different (DFA) algorithm. Although it is slower than the original
function, it does have some advantages for certain types of matching
5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
including restarting after a partial match.
6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
defined when compiling for Windows was sent to me. I have put it into the
code, though I have no means of testing or verifying it.
7. Added the pcre_refcount() auxiliary function.
8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
match before or at the first newline in the subject string. In pcretest,
the /f option on a pattern can be used to set this.
9. A repeated \w when used in UTF-8 mode with characters greater than 256
would behave wrongly. This has been present in PCRE since release 4.0.
10. A number of changes to the pcregrep command:
(a) Refactored how -x works; insert ^(...)$ instead of setting
PCRE_ANCHORED and checking the length, in preparation for adding
something similar for -w.
(b) Added the -w (match as a word) option.
(c) Refactored the way lines are read and buffered so as to have more
than one at a time available.
(d) Implemented a pcregrep test script.
(e) Added the -M (multiline match) option. This allows patterns to match
over several lines of the subject. The buffering ensures that at least
8K, or the rest of the document (whichever is the shorter) is available
for matching (and similarly the previous 8K for lookbehind assertions).
(f) Changed the --help output so that it now says
-w, --word-regex(p)
instead of two lines, one with "regex" and the other with "regexp"
because that confused at least one person since the short forms are the
same. (This required a bit of code, as the output is generated
automatically from a table. It wasn't just a text change.)
(g) -- can be used to terminate pcregrep options if the next thing isn't an
option but starts with a hyphen. Could be a pattern or a path name
starting with a hyphen, for instance.
(h) "-" can be given as a file name to represent stdin.
(i) When file names are being printed, "(standard input)" is used for
the standard input, for compatibility with GNU grep. Previously
"<stdin>" was used.
(j) The option --label=xxx can be used to supply a name to be used for
stdin when file names are being printed. There is no short form.
(k) Re-factored the options decoding logic because we are going to add
two more options that take data. Such options can now be given in four
different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
(l) Added the -A, -B, and -C options for requesting that lines of context
around matches be printed.
(m) Added the -L option to print the names of files that do not contain
any matching lines, that is, the complement of -l.
(n) The return code is 2 if any file cannot be opened, but pcregrep does
continue to scan other files.
(o) The -s option was incorrectly implemented. For compatibility with other
greps, it now suppresses the error message for a non-existent or non-
accessible file (but not the return code). There is a new option called
-q that suppresses the output of matching lines, which was what -s was
previously doing.
(p) Added --include and --exclude options to specify files for inclusion
and exclusion when recursing.
11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
Hopefully, it now does.
12. Missing cast in pcre_study().
13. Added an "uninstall" target to the makefile.
14. Replaced "extern" in the function prototypes in with
"PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
world, but is set differently for Windows.
15. Added a second compiling function called pcre_compile2(). The only
difference is that it has an extra argument, which is a pointer to an
integer error code. When there is a compile-time failure, this is set
non-zero, in addition to the error test pointer being set to point to an
error message. The new argument may be NULL if no error number is required
(but then you may as well call pcre_compile(), which is now just a
wrapper). This facility is provided because some applications need a
numeric error indication, but it has also enabled me to tidy up the way
compile-time errors are handled in the POSIX wrapper.
16. Added VPATH=.libs to the makefile; this should help when building with one
prefix path and installing with another. (Or so I'm told by someone who
knows more about this stuff than I do.)
17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
passes PCRE_DOTALL to the pcre_compile() function, making the "." character
match everything, including newlines. This is not POSIX-compatible, but
somebody wanted the feature. From pcretest it can be activated by using
both the P and the s flags.
18. AC_PROG_LIBTOOL appeared twice in Removed one.
19. libpcre.pc was being incorrectly installed as executable.
20. A couple of places in pcretest check for end-of-line by looking for '\n';
it now also looks for '\r' so that it will work unmodified on Windows.
21. Added Google's contributed C++ wrapper to the distribution.
22. Added some untidy missing memory free() calls in pcretest, to keep
Electric Fence happy when testing.
Version 5.0 13-Sep-04
1. Internal change: literal characters are no longer packed up into items
containing multiple characters in a single byte-string. Each character
is now matched using a separate opcode. However, there may be more than one
byte in the character in UTF-8 mode.
2. The pcre_callout_block structure has two new fields: pattern_position and
next_item_length. These contain the offset in the pattern to the next match
item, and its length, respectively.
3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
insertion of callouts before each pattern item. Added the /C option to
pcretest to make use of this.
4. On the advice of a Windows user, the lines
#if defined(_WIN32) || defined(WIN32)
_setmode( _fileno( stdout ), 0x8000 );
#endif /* defined(_WIN32) || defined(WIN32) */
have been added to the source of pcretest. This apparently does useful
magic in relation to line terminators.
5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
for the benefit of those environments where the "b" makes a difference.
6. The icc compiler has the same options as gcc, but "configure" doesn't seem
to know about it. I have put a hack into that adds in code
to set GCC=yes if CC=icc. This seems to end up at a point in the
generated configure script that is early enough to affect the setting of
compiler options, which is what is needed, but I have no means of testing
whether it really works. (The user who reported this had patched the
generated configure script, which of course I cannot do.)
LATER: After change 22 below (new libtool files), the configure script
seems to know about icc (and also ecc). Therefore, I have commented out
this hack in
7. Added support for pkg-config (2 patches were sent in).
8. Negated POSIX character classes that used a combination of internal tables
were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
[[:^ascii]]. Typically, they would match almost any characters. The other
POSIX classes were not broken in this way.
9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
to find the match, as PCRE was deluded into thinking that the match had to
start at the start point or following a newline. The same bug applied to
patterns with negative forward assertions or any backward assertions
preceding ".*" at the start, unless the pattern required a fixed first
character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
10. In UTF-8 mode, when moving forwards in the subject after a failed match
starting at the last subject character, bytes beyond the end of the subject
string were read.
11. Renamed the variable "class" as "classbits" to make life easier for C++
users. (Previously there was a macro definition, but it apparently wasn't
12. Added the new field "tables" to the extra data so that tables can be passed
in at exec time, or the internal tables can be re-selected. This allows
a compiled regex to be saved and re-used at a later time by a different
program that might have everything at different addresses.
13. Modified the pcre-config script so that, when run on Solaris, it shows a
-R library as well as a -L library.
14. The debugging options of pcretest (-d on the command line or D on a
pattern) showed incorrect output for anything following an extended class
that contained multibyte characters and which was followed by a quantifier.
15. Added optional support for general category Unicode character properties
via the \p, \P, and \X escapes. Unicode property support implies UTF-8
support. It adds about 90K to the size of the library. The meanings of the
inbuilt class escapes such as \d and \s have NOT been changed.
16. Updated pcredemo.c to include calls to free() to release the memory for the
compiled pattern.
17. The generated file chartables.c was being created in the source directory
instead of in the building directory. This caused the build to fail if the
source directory was different from the building directory, and was
18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
file. No doubt somebody will tell me if they don't make sense... Also added
Dan Mooney's comments about building on OpenVMS.
19. Added support for partial matching via the PCRE_PARTIAL option for
pcre_exec() and the \P data escape in pcretest.
20. Extended pcretest with 3 new pattern features:
(i) A pattern option of the form ">rest-of-line" causes pcretest to
write the compiled pattern to the file whose name is "rest-of-line".
This is a straight binary dump of the data, with the saved pointer to
the character tables forced to be NULL. The study data, if any, is
written too. After writing, pcretest reads a new pattern.
(ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
compiled pattern from the given file. There must not be any
occurrences of "<" in the file name (pretty unlikely); if there are,
pcretest will instead treat the initial "<" as a pattern delimiter.
After reading in the pattern, pcretest goes on to read data lines as
(iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
and 16-bit fields in a compiled pattern, to simulate a pattern that
was compiled on a host of opposite endianness.
21. The pcre-exec() function can now cope with patterns that were compiled on
hosts of opposite endianness, with this restriction:
As for any compiled expression that is saved and used later, the tables
pointer field cannot be preserved; the extra_data field in the arguments
to pcre_exec() should be used to pass in a tables address if a value
other than the default internal tables were used at compile time.
22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
now diagnosed as an error. Previously, most of the time, a negative number
would have been treated as zero, but if in addition "ovector" was passed as
NULL, a crash could occur.
23. Updated the files, config.sub, config.guess, and aclocal.m4 with
new versions from the libtool 1.5 distribution (the last one is a copy of
a file called libtool.m4). This seems to have fixed the need to patch
"configure" to support Darwin 1.3 (which I used to do). However, I still
had to patch to ensure that ${SED} is set (it isn't on my
24. Changed the PCRE licence to be the more standard "BSD" licence.
Version 4.5 01-Dec-03
1. There has been some re-arrangement of the code for the match() function so
that it can be compiled in a version that does not call itself recursively.
Instead, it keeps those local variables that need separate instances for
each "recursion" in a frame on the heap, and gets/frees frames whenever it
needs to "recurse". Keeping track of where control must go is done by means
of setjmp/longjmp. The whole thing is implemented by a set of macros that
hide most of the details from the main code, and operates only if
NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
"configure" mechanism, "--disable-stack-for-recursion" turns on this way of
To make it easier for callers to provide specially tailored get/free
functions for this usage, two new functions, pcre_stack_malloc, and
pcre_stack_free, are used. They are always called in strict stacking order,
and the size of block requested is always the same.
The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
PCRE has been compiled to use the stack or the heap for recursion. The
-C option of pcretest uses this to show which version is compiled.
A new data escape \S, is added to pcretest; it causes the amounts of store
obtained and freed by both kinds of malloc/free at match time to be added
to the output.
2. Changed the locale test to use "fr_FR" instead of "fr" because that's
what's available on my current Linux desktop machine.
3. When matching a UTF-8 string, the test for a valid string at the start has
been extended. If start_offset is not zero, PCRE now checks that it points
to a byte that is the start of a UTF-8 character. If not, it returns
PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
this is necessary because there may be backward assertions in the pattern.
When matching the same subject several times, it may save resources to use
PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
4. The code for checking the validity of UTF-8 strings has been tightened so
that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
containing "overlong sequences".
5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
should have been "&", but it just so happened that all the cases this let
through by mistake were picked up later in the function.
6. I had used a variable called "isblank" - this is a C99 function, causing
some compilers to warn. To avoid this, I renamed it (as "blankclass").
7. Cosmetic: (a) only output another newline at the end of pcretest if it is
prompting; (b) run "./pcretest /dev/null" at the start of the test script
so the version is shown; (c) stop "make test" echoing "./RunTest".
8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
9. The prototype for memmove() for systems that don't have it was using
size_t, but the inclusion of the header that defines size_t was later. I've
moved the #includes for the C headers earlier to avoid this.
10. Added some adjustments to the code to make it easier to compiler on certain
special systems:
(a) Some "const" qualifiers were missing.
(b) Added the macro EXPORT before all exported functions; by default this
is defined to be empty.
(c) Changed the dftables auxiliary program (that builds chartables.c) so
that it reads its output file name as an argument instead of writing
to the standard output and assuming this can be redirected.
11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
class containing characters with values greater than 255, PCRE compilation
went into a loop.
12. A recursive reference to a subpattern that was within another subpattern
that had a minimum quantifier of zero caused PCRE to crash. For example,
(x(y(?2))z)? provoked this bug with a subject that got as far as the
recursion. If the recursively-called subpattern itself had a zero repeat,
that was OK.
13. In pcretest, the buffer for reading a data line was set at 30K, but the
buffer into which it was copied (for escape processing) was still set at
1024, so long lines caused crashes.
14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
"internal error: code overflow...". This applied to any character class
that was followed by a possessive quantifier.
15. Modified the Makefile to add as a prerequisite for because I was told this is needed for a parallel build to
16. If a pattern that contained .* following optional items at the start was
studied, the wrong optimizing data was generated, leading to matching
errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
matching string must start with a or b or c. The correct conclusion for
this pattern is that a match can start with any character.
Version 4.4 13-Aug-03
1. In UTF-8 mode, a character class containing characters with values between
127 and 255 was not handled correctly if the compiled pattern was studied.
In fixing this, I have also improved the studying algorithm for such
classes (slightly).
2. Three internal functions had redundant arguments passed to them. Removal
might give a very teeny performance improvement.
3. Documentation bug: the value of the capture_top field in a callout is *one
more than* the number of the hightest numbered captured substring.
4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
in incorrectly linking with a previously installed version. They now link
explicitly with
5. no longer needs to recognize Cygwin specially.
6. A problem in for Windows platforms is fixed.
7. If a pattern was successfully studied, and the -d (or /D) flag was given to
pcretest, it used to include the size of the study block as part of its
output. Unfortunately, the structure contains a field that has a different
size on different hardware architectures. This meant that the tests that
showed this size failed. As the block is currently always of a fixed size,
this information isn't actually particularly useful in pcretest output, so
I have just removed it.
8. Three pre-processor statements accidentally did not start in column 1.
Sadly, there are *still* compilers around that complain, even though
standard C has not required this for well over a decade. Sigh.
9. In pcretest, the code for checking callouts passed small integers in the
callout_data field, which is a void * field. However, some picky compilers
complained about the casts involved for this on 64-bit systems. Now
pcretest passes the address of the small integer instead, which should get
rid of the warnings.
10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
both compile and run time, and gives an error if an invalid UTF-8 sequence
is found. There is a option for disabling this check in cases where the
string is known to be correct and/or the maximum performance is wanted.
11. In response to a bug report, I changed one line in from
-Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
-Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
to look similar to other lines, but I have no way of telling whether this
is the right thing to do, as I do not use Windows. No doubt I'll get told
if it's wrong...
Version 4.3 21-May-03
1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2. Some refactoring to improve the quality of the code:
(i) The utf8_table... variables are now declared "const".
(ii) The code for \cx, which used the "case flipping" table to upper case
lower case letters, now just substracts 32. This is ASCII-specific,
but the whole concept of \cx is ASCII-specific, so it seems
(iii) PCRE was using its character types table to recognize decimal and
hexadecimal digits in the pattern. This is silly, because it handles
only 0-9, a-f, and A-F, but the character types table is locale-
specific, which means strange things might happen. A private
table is now used for this - though it costs 256 bytes, a table is
much faster than multiple explicit tests. Of course, the standard
character types table is still used for matching digits in subject
strings against \d.
(iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
ending in _t are). So I've renamed it as ESC_tee.
3. The first argument for regexec() in the POSIX wrapper should have been
defined as "const".
4. Changed pcretest to use malloc() for its buffers so that they can be
Electric Fenced for debugging.
5. There were several places in the code where, in UTF-8 mode, PCRE would try
to read one or more bytes before the start of the subject string. Often this
had no effect on PCRE's behaviour, but in some circumstances it could
provoke a segmentation fault.
6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
to try to read one or more bytes before the start of the subject string.
7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
UTF-8 support could misbehave in various ways if the subject string
contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
back over UTF-8 characters.)
Version 4.2 14-Apr-03
1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2. Changes to the building process, supplied by Ronald Landheer-Cieslak
[ON_WINDOWS]: new variable, "#" on non-Windows platforms
[NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
[WIN_PREFIX]: new variable, "cyg" for Cygwin
* use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
Note: automatic setting of the BUILD variables is not yet working
set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
compile-time but not at link-time
[LINK]: use for linking executables only
make different versions for Windows and non-Windows
[LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
[LINK_FOR_BUILD]: new variable
[OBJEXT]: use throughout
[EXEEXT]: use throughout
<winshared>: new target
<wininstall>: new target
<dftables.o>: use native compiler
<dftables>: use native linker
<install>: handle Windows platform correctly
<clean>: ditto
<check>: ditto
copy DLL to top builddir before testing
As part of these changes, -no-undefined was removed again. This was reported
to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
in any case.
3. Some tidies to get rid of compiler warnings:
. In the match_data structure, match_limit was an unsigned long int, whereas
match_call_count was an int. I've made them both unsigned long ints.
. In pcretest the fact that a const uschar * doesn't automatically cast to
a void * provoked a warning.
. Turning on some more compiler warnings threw up some "shadow" variables
and a few more missing casts.
4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
option, a class that contained a single character with a value between 128
and 255 (e.g. /[\xFF]/) caused PCRE to crash.
5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
option, a class that contained several characters, but with at least one
whose value was between 128 and 255 caused PCRE to crash.
Version 4.1 12-Mar-03
1. Compiling with gcc -pedantic found a couple of places where casts were
needed, and a string in dftables.c that was longer than standard compilers are
required to support.
2. Compiling with Sun's compiler found a few more places where the code could
be tidied up in order to avoid warnings.
3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
first of these names is deprecated in the latest Autoconf in favour of the name
CC_FOR_BUILD, because "host" is typically used to mean the system on which the
compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
analogy I have changed it to CFLAGS_FOR_BUILD.
4. Added -no-undefined to the linking command in the Makefile, because this is
apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
linking step for the pcreposix library.
5. PCRE was failing to diagnose the case of two named groups with the same
6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
literal character that is needed in the subject for a match, and scans along to
ensure that it is present before embarking on the full matching process. This
saves time in cases of nested unlimited repeats that are never going to match.
Problem: the scan can take a lot of time if the subject is very long (e.g.
megabytes), thus penalizing straightforward matches. It is now done only if the
amount of subject to be scanned is less than 1000 bytes.
7. A lesser problem with the same optimization is that it was recording the
first character of an anchored pattern as "needed", thus provoking a search
right along the subject, even when the first match of the pattern was going to
fail. The "needed" character is now not set for anchored patterns, unless it
follows something in the pattern that is of non-fixed length. Thus, it still
fulfils its original purpose of finding quick non-matches in cases of nested
unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
Version 4.0 17-Feb-03
1. If a comment in an extended regex that started immediately after a meta-item
extended to the end of string, PCRE compiled incorrect data. This could lead to
all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2. Moved to autoconf 2.53 and libtool 1.4.2.
3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
the special perltest8 script is no longer needed - all the tests can be run
from a single perltest script.
4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
by \s. It has now been removed in PCRE. This means it isn't recognized as
whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
class [:space:] *does* include VT, thereby creating a mess.
5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
space and tab.
6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
its new features into the main test script, reducing the number of scripts.
7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
were backward compatible, and made the (?i) apply to the whole pattern, as if
/i were given. Now it behaves more logically, and applies the option setting
only to what follows. PCRE has been changed to follow suit. However, if it
finds options settings right at the start of the pattern, it extracts them into
the global options, as before. Thus, they show up in the info data.
8. Added support for the \Q...\E escape sequence. Characters in between are
treated as literals. This is slightly different from Perl in that $ and @ are
also handled as literals inside the quotes. In Perl, they will cause variable
interpolation. Note the following examples:
Pattern PCRE matches Perl matches
\Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
\Qabc\$xyz\E abc\$xyz abc\$xyz
\Qabc\E\$\Qxyz\E abc$xyz abc$xyz
For compatibility with Perl, \Q...\E sequences are recognized inside character
classes as well as outside them.
9. Re-organized 3 code statements in pcretest to avoid "overflow in
floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
(size_t) cast to one statement in pcretest and one in pcreposix to avoid
signed/unsigned warnings.
10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
option for pcretest, so I've replaced it by a simple function that does just
that job.
11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
"pcregrep -".
12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
Java package. This provides some syntactic sugar for simple cases of what my
documentation calls "once-only subpatterns". A pattern such as x*+ is the same
as (?>x*). In other words, if what is inside (?>...) is just a single repeated
item, you can use this simplified notation. Note that only makes sense with
greedy quantifiers. Consequently, the use of the possessive quantifier forces
greediness, whatever the setting of the PCRE_UNGREEDY option.
13. A change of greediness default within a pattern was not taking effect at
the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
was abstracted outside.
14. PCRE now supports the \G assertion. It is true when the current matching
position is at the start point of the match. This differs from \A when the
starting offset is non-zero. Used with the /g option of pcretest (or similar
code), it works in the same way as it does for Perl's /g option. If all
alternatives of a regex begin with \G, the expression is anchored to the start
match position, and the "anchored" flag is set in the compiled expression.
15. Some bugs concerning the handling of certain option changes within patterns
have been fixed. These applied to options other than (?ims). For example,
"a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
been the other way round. Some of this was related to change 7 above.
16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
POSIX classes only within a class (e.g. /[[:alpha:]]/).
17. Added support for Perl's \C escape. This matches one byte, even in UTF8
mode. Unlike ".", it always matches newline, whatever the setting of
PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
assertions. Perl allows it, but it doesn't (in general) work because it can't
calculate the length of the lookbehind. At least, that's the case for Perl
5.8.0 - I've been told they are going to document that it doesn't work in
18. Added an error diagnosis for escapes that PCRE does not support: these are
\L, \l, \N, \P, \p, \U, \u, and \X.
19. Although correctly diagnosing a missing ']' in a character class, PCRE was
reading past the end of the pattern in cases such as /[abcd/.
20. PCRE was getting more memory than necessary for patterns with classes that
contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
compiling PCRE for use with Virtual Pascal.
22. Small fix to the Makefile to make it work properly if the build is done
outside the source tree.
23. Added a new extension: a condition to go with recursion. If a conditional
subpattern starts with (?(R) the "true" branch is used if recursion has
happened, whereas the "false" branch is used only at the top level.
24. When there was a very long string of literal characters (over 255 bytes
without UTF support, over 250 bytes with UTF support), the computation of how
much memory was required could be incorrect, leading to segfaults or other
strange effects.
25. PCRE was incorrectly assuming anchoring (either to start of subject or to
start of line for a non-DOTALL pattern) when a pattern started with (.*) and
there was a subsequent back reference to those brackets. This meant that, for
example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
possible to check for precisely this case. All we can do is abandon the
optimization if .* occurs inside capturing brackets when there are any back
references whatsoever. (See below for a better fix that came later.)
26. The handling of the optimization for finding the first character of a
non-anchored pattern, and for finding a character that is required later in the
match were failing in some cases. This didn't break the matching; it just
failed to optimize when it could. The way this is done has been re-implemented.
27. Fixed typo in error message for invalid (?R item (it said "(?p").
28. Added a new feature that provides some of the functionality that Perl
provides with (?{...}). The facility is termed a "callout". The way it is done
in PCRE is for the caller to provide an optional function, by setting
pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
global variable. By default it is unset, which disables all calling out. To get
the function called, the regex must include (?C) at appropriate points. This
is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
This provides a means of identifying different callout points. When PCRE
reaches such a point in the regex, if pcre_callout has been set, the external
function is called. It is provided with data in a structure called
pcre_callout_block, which is defined in pcre.h. If the function returns 0,
matching continues; if it returns a non-zero value, the match at the current
point fails. However, backtracking will occur if possible. [This was changed
later and other features added - see item 49 below.]
29. pcretest is upgraded to test the callout functionality. It provides a
callout function that displays information. By default, it shows the start of
the match and the current position in the text. There are some new data escapes
to vary what happens:
\C+ in addition, show current contents of captured substrings
\C- do not supply a callout function
\C!n return 1 when callout number n is reached
\C!n!m return 1 when callout number n is reached for the mth time
30. If pcregrep was called with the -l option and just a single file name, it
output "<stdin>" if a match was found, instead of the file name.
31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
pcre_exec(). This saves a malloc/free per call. The default value of
POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
when configuring.
32. The default maximum size of a compiled pattern is 64K. There have been a
few cases of people hitting this limit. The code now uses macros to handle the
storing of links as offsets within the compiled pattern. It defaults to 2-byte
links, but this can be changed to 3 or 4 bytes by --with-link-size when
configuring. Tests 2 and 5 work only with 2-byte links because they output
debugging information about compiled patterns.
33. Internal code re-arrangements:
(a) Moved the debugging function for printing out a compiled regex into
its own source file (printint.c) and used #include to pull it into
pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
separate copies.
(b) Defined the list of op-code names for debugging as a macro in
internal.h so that it is next to the definition of the opcodes.
(c) Defined a table of op-code lengths for simpler skipping along compiled
code. This is again a macro in internal.h so that it is next to the
definition of the opcodes.
34. Added support for recursive calls to individual subpatterns, along the
lines of Robin Houston's patch (but implemented somewhat differently).
35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
allow it to read and process whole directories in Win32. This code was
contributed by Lionel Fourquaux; it has not been tested by me.
36. Added support for named subpatterns. The Python syntax (?P<name>...) is
used to name a group. Names consist of alphanumerics and underscores, and must
be unique. Back references use the syntax (?P=name) and recursive calls use
(?P>name) which is a PCRE extension to the Python extension. Groups still have
numbers. The function pcre_fullinfo() can be used after compilation to extract
a name/number map. There are three relevant calls:
PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
PCRE_INFO_NAMECOUNT yields the number of entries
PCRE_INFO_NAMETABLE yields a pointer to the map.
The map is a vector of fixed-size entries. The size of each entry depends on
the length of the longest name used. The first two bytes of each entry are the
group number, most significant byte first. There follows the corresponding
name, zero terminated. The names are in alphabetical order.
37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
case instead of 255. Making it the same both with and without UTF-8 support
means that the same test output works with both.
38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
calling malloc() with a zero argument.
39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
optimization. I've improved things by keeping a bitmap of backreferences with
numbers 1-31 so that if .* occurs inside capturing brackets that are not in
fact referenced, the optimization can be applied. It is unlikely that a
relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
the match to follow \n) will appear inside brackets with a number greater than
31, but if it does, any back reference > 31 suppresses the optimization.
40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
of disabling numbered capturing parentheses. Any opening parenthesis that is
not followed by ? behaves as if it were followed by ?: but named parentheses
can still be used for capturing (and they will acquire numbers in the usual
41. Redesigned the return codes from the match() function into yes/no/error so
that errors can be passed back from deep inside the nested calls. A malloc
failure while inside a recursive subpattern call now causes the
PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
42. It is now possible to set a limit on the number of times the match()
function is called in a call to pcre_exec(). This facility makes it possible to
limit the amount of recursion and backtracking, though not in a directly
obvious way, because the match() function is used in a number of different
circumstances. The count starts from zero for each position in the subject
string (for non-anchored patterns). The default limit is, for compatibility, a
large number, namely 10 000 000. You can change this in two ways:
(a) When configuring PCRE before making, you can use --with-match-limit=n
to set a default value for the compiled library.
(b) For each call to pcre_exec(), you can pass a pcre_extra block in which
a different value is set. See 45 below.
If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
43. Added a new function pcre_config(int, void *) to enable run-time extraction
of things that can be changed at compile time. The first argument specifies
what is wanted and the second points to where the information is to be placed.
The current list of available information is:
The output is an integer that is set to one if UTF-8 support is available;
otherwise it is set to zero.
The output is an integer that it set to the value of the code that is used for
newline. It is either LF (10) or CR (13).
The output is an integer that contains the number of bytes used for internal
linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
The output is an integer that contains the threshold above which the POSIX
interface uses malloc() for output vectors. See item 31 above.
The output is an unsigned integer that contains the default limit of the number
of match() calls in a pcre_exec() execution. See 42 above.
44. pcretest has been upgraded by the addition of the -C option. This causes it
to extract all the available output from the new pcre_config() function, and to
output it. The program then exits immediately.
45. A need has arisen to pass over additional data with calls to pcre_exec() in
order to support additional features. One way would have been to define
pcre_exec2() (for example) with extra arguments, but this would not have been
extensible, and would also have required all calls to the original function to
be mapped to the new one. Instead, I have chosen to extend the mechanism that
is used for passing in "extra" data from pcre_study().
The pcre_extra structure is now exposed and defined in pcre.h. It currently
contains the following fields:
flags a bitmap indicating which of the following fields are set
study_data opaque data from pcre_study()
match_limit a way of specifying a limit on match() calls for a specific
call to pcre_exec()
callout_data data for callouts (see 49 below)
The flag bits are also defined in pcre.h, and are
The pcre_study() function now returns one of these new pcre_extra blocks, with
the actual study data pointed to by the study_data field, and the
PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
before. That is, this change is entirely upwards-compatible and requires no
change to existing code.
If you want to pass in additional data to pcre_exec(), you can either place it
in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
data string contains the escape sequence \M, pcretest calls pcre_exec() several
times with different match limits, until it finds the minimum value needed for
pcre_exec() to complete. The value is then output. This can be instructive; for
most simple matches the number is quite small, but for pathological cases it
gets very large very quickly.
47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
returns the size of the data block pointed to by the study_data field in a
pcre_extra block, that is, the value that was passed as the argument to
pcre_malloc() when PCRE was getting memory in which to place the information
created by pcre_study(). The fourth argument should point to a size_t variable.
pcretest has been extended so that this information is shown after a successful
pcre_study() call when information about the compiled regex is being displayed.
48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
because what follows is always an absolute path. (Later: it turns out that this
is more than cosmetic for MinGW, because it doesn't like empty path
49. Some changes have been made to the callout feature (see 28 above):
(i) A callout function now has three choices for what it returns:
0 => success, carry on matching
> 0 => failure at this point, but backtrack if possible
< 0 => serious error, return this value from pcre_exec()
Negative values should normally be chosen from the set of PCRE_ERROR_xxx
values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
"match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
use by callout functions. It will never be used by PCRE itself.
(ii) The pcre_extra structure (see 45 above) has a void * field called
callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
pcre_callout_block structure has a field of the same name. The contents of
the field passed in the pcre_extra structure are passed to the callout
function in the corresponding field in the callout block. This makes it
easier to use the same callout-containing regex from multiple threads. For
testing, the pcretest program has a new data escape
\C*n pass the number n (may be negative) as callout_data
If the callout function in pcretest receives a non-zero value as
callout_data, it returns that value.
50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
there were some redundant $(CFLAGS) in commands that are now specified as
$(LINK), which already includes $(CFLAGS).
51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
has been compiled with UTF-8 support *and* pcre_compile() has been compiled
with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
one-byte characters throughout. Note that case-insensitive matching applies
only to characters whose values are less than 256. PCRE doesn't support the
notion of cases for higher-valued characters.
(i) A character class whose characters are all within 0-255 is handled as
a bit map, and the map is inverted for negative classes. Previously, a
character > 255 always failed to match such a class; however it should
match if the class was a negative one (e.g. [^ab]). This has been fixed.
(ii) A negated character class with a single character < 255 is coded as
"not this character" (OP_NOT). This wasn't working properly when the test
character was multibyte, either singly or repeated.
(iii) Repeats of multibyte characters are now handled correctly in UTF-8
mode, for example: \x{100}{2,3}.
(iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
singly or repeated) now correctly test multibyte characters. However,
PCRE doesn't recognize any characters with values greater than 255 as
digits, spaces, or word characters. Such characters always match \D, \S,
and \W, and never match \d, \s, or \w.
(v) Classes may now contain characters and character ranges with values
greater than 255. For example: [ab\x{100}-\x{400}].
(vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
PCRE in UTF-8 mode.
52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
retained for backwards compatibility. (Note that LASTLITERAL is also a byte
53. The single man page has become too large. I have therefore split it up into
a number of separate man pages. These also give rise to individual HTML pages;
these are now put in a separate directory, and there is an index.html page that
lists them all. Some hyperlinking between the pages has been installed.
54. Added convenience functions for handling named capturing parentheses.
55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
are faulted.
56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
calling configure. These values are used when compiling the dftables.c program
which is run to generate the source of the default character tables. They
default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
you will need to set these values.
57. Updated the building process for Windows DLL, as provided by Fred Cox.
Version 3.9 02-Jan-02
1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2. If --disable-static was given, the building process failed when trying to
build pcretest and pcregrep. (For some reason it was using libtool to compile
them, which is not right, as they aren't part of the library.)
Version 3.8 18-Dec-01
1. The experimental UTF-8 code was completely screwed up. It was packing the
bytes in the wrong order. How dumb can you get?
Version 3.7 29-Oct-01
1. In updating pcretest to check change 1 of version 3.6, I screwed up.
This caused pcretest, when used on the test data, to segfault. Unfortunately,
this didn't happen under Solaris 8, where I normally test things.
2. The Makefile had to be changed to make it work on BSD systems, where 'make'
doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
this fix an hour or so after the initial 3.7 release.)
Version 3.6 23-Oct-01
1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
offsets passed as NULL with zero offset count.
2. The config.guess and config.sub files had not been updated when I moved to
the latest autoconf.
Version 3.5 15-Aug-01
1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
had been forgotten.
2. By using declared but undefined structures, we can avoid using "void"
definitions in pcre.h while keeping the internal definitions of the structures
3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
user point of view, this means that both static and shared libraries are built
by default, but this can be individually controlled. More of the work of
handling this static/shared cases is now inside libtool instead of PCRE's make
4. The pcretest utility is now installed along with pcregrep because it is
useful for users (to test regexs) and by doing this, it automatically gets
relinked by libtool. The documentation has been turned into a man page, so
there are now .1, .txt, and .html versions in /doc.
5. Upgrades to pcregrep:
(i) Added long-form option names like gnu grep.
(ii) Added --help to list all options with an explanatory phrase.
(iii) Added -r, --recursive to recurse into sub-directories.
(iv) Added -f, --file to read patterns from a file.
6. pcre_exec() was referring to its "code" argument before testing that
argument for NULL (and giving an error if it was NULL).
7. Upgraded to allow for compiling in a different directory from
the source directory.
8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
options bits, the pointer it was passed was to an int instead of to an unsigned
long int. This mattered only on 64-bit systems.
9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
generated) instead of, which it its source. Also made the same change
in several of the .c files.
10. A new release of gcc defines printf() as a macro, which broke pcretest
because it had an ifdef in the middle of a string argument for printf(). Fixed
by using separate calls to printf().
11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
script, to force use of CR or LF instead of \n in the source. On non-Unix
systems, the value can be set in config.h.
12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
absolute limit. Changed the text of the error message to make this clear, and
likewise updated the man page.
13. The limit of 99 on the number of capturing subpatterns has been removed.
The new limit is 65535, which I hope will not be a "real" limit.
Version 3.4 22-Aug-00
1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2. Diagnose condition (?(0) as an error instead of crashing on matching.
Version 3.3 01-Aug-00
1. If an octal character was given, but the value was greater than \377, it
was not getting masked to the least significant bits, as documented. This could
lead to crashes in some systems.
2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3. Added the functions pcre_free_substring() and pcre_free_substring_list().
These just pass their arguments on to (pcre_free)(), but they are provided
because some uses of PCRE bind it to non-C systems that can call its functions,
but cannot call free() or pcre_free() directly.
4. Add "make test" as a synonym for "make check". Corrected some comments in
the Makefile.
5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
command called pgrep for grepping around the active processes.
7. Added the beginnings of support for UTF-8 character strings.
8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
RANLIB to ./ltconfig so that they are used by libtool. I think these are all
the relevant ones. (AR is not passed because ./ltconfig does its own figuring
out for the ar command.)
Version 3.2 12-May-00
This is purely a bug fixing release.
1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
of ZA. This was just one example of several cases that could provoke this bug,
which was introduced by change 9 of version 2.00. The code for breaking
infinite loops after an iteration that matches an empty string was't working
2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
when matched against abbab (for example). After matching an empty string, it
wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
caused it to match further down the string than it should.
3. The code contained an inclusion of sys/types.h. It isn't clear why this
was there because it doesn't seem to be needed, and it causes trouble on some
systems, as it is not a Standard C header. It has been removed.
4. Made 4 silly changes to the source to avoid stupid compiler warnings that
were reported on the Macintosh. The changes were from
while ((c = *(++ptr)) != 0 && c != '\n');
while ((c = *(++ptr)) != 0 && c != '\n') ;
Totally extraordinary, but if that's what it takes...
5. PCRE is being used in one environment where neither memmove() nor bcopy() is
available. Added HAVE_BCOPY and an autoconf test for it; if neither
HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
assumes the way PCRE uses memmove() (always moving upwards).
6. PCRE is being used in one environment where strchr() is not available. There
was only one use in pcre.c, and writing it out to avoid strchr() probably gives
faster code anyway.
Version 3.1 09-Feb-00
The only change in this release is the fixing of some bugs in for
the "install" target:
(1) It was failing to install pcreposix.h.
(2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
Version 3.0 01-Feb-00
1. Add support for the /+ modifier to perltest (to output $` like it does in
2. Add support for the /g modifier to perltest.
3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
matches null strings.
4. Fix perltest so that it doesn't do unwanted things when fed an empty
pattern. Perl treats empty patterns specially - it reuses the most recent
pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
5. The POSIX interface was broken in that it was just handing over the POSIX
captured string vector to pcre_exec(), but (since release 2.00) PCRE has
required a bigger vector, with some working space on the end. This means that
the POSIX wrapper now has to get and free some memory, and copy the results.
6. Added some simple autoconf support, placing the test data and the
documentation in separate directories, re-organizing some of the
information files, and making it build pcre-config (a GNU standard). Also added
libtool support for building PCRE as a shared library, which is now the
7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
09 are not valid octal constants. Single digits will be used for minor values
less than 10.
8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
existing programs that set these in the POSIX interface can use PCRE without
9. Added a new function, pcre_fullinfo() with an extensible interface. It can
return all that pcre_info() returns, plus additional data. The pcre_info()
function is retained for compatibility, but is considered to be obsolete.
10. Added experimental recursion feature (?R) to handle one common case that
Perl 5.6 will be able to do with (?p{...}).
11. Added support for POSIX character classes like [:alpha:], which Perl is
Version 2.08 31-Aug-99
1. When startoffset was not zero and the pattern began with ".*", PCRE was not
trying to match at the startoffset position, but instead was moving forward to
the next newline as if a previous match had failed.
2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
and could get into a loop if a null string was matched other than at the start
of the subject.
3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
be distinguished at compile time, and for completeness also added PCRE_DATE.
5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
in GnuWin32 environments.
Version 2.07 29-Jul-99
1. The documentation is now supplied in plain text form and HTML as well as in
the form of man page sources.
2. C++ compilers don't like assigning (void *) values to other pointer types.
In particular this affects malloc(). Although there is no problem in Standard
C, I've put in casts to keep C++ compilers happy.
3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
should be (const char *).
4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
be useful for non-Unix systems who don't want to bother with the POSIX stuff.
However, I haven't made this a standard facility. The documentation doesn't
mention it, and the Makefile doesn't support it.
5. The Makefile now contains an "install" target, with editable destinations at
the top of the file. The pcretest program is not installed.
6. pgrep -V now gives the PCRE version number and date.
7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
causing the entire string to be ignored, instead of just the last character.
8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
non-matching string, it can take a very, very long time, even for strings of
quite modest length, because of the nested recursion. PCRE now does better in
some of these cases. It does this by remembering the last required literal
character in the pattern, and pre-searching the subject to ensure it is present
before running the real match. In other words, it applies a heuristic to detect
some types of certain failure quickly, and in the above example, if presented
with a string that has no trailing " it gives "no match" very quickly.
9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
other alternatives are tried instead.
Version 2.06 09-Jun-99
1. Change pcretest's output for amount of store used to show just the code
space, because the remainder (the data block) varies in size between 32-bit and
64-bit systems.
2. Added an extra argument to pcre_exec() to supply an offset in the subject to
start matching at. This allows lookbehinds to work when searching for multiple
occurrences in a string.
3. Added additional options to pcretest for testing multiple occurrences:
/+ outputs the rest of the string that follows a match
/g loops for multiple occurrences, using the new startoffset argument
/G loops for multiple occurrences by passing an incremented pointer
4. PCRE wasn't doing the "first character" optimization for patterns starting
with \b or \B, though it was doing it for other lookbehind assertions. That is,
it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
the letter 'x'. On long subject strings, this gives a significant speed-up.
Version 2.05 21-Apr-99
1. Changed the type of magic_number from int to long int so that it works
properly on 16-bit systems.
2. Fixed a bug which caused patterns starting with .* not to work correctly
when the subject string contained newline characters. PCRE was assuming
anchoring for such patterns in all cases, which is not correct because .* will
not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
DOTALL is set at top level; otherwise it knows that patterns starting with .*
must be retried after every newline in the subject.
Version 2.04 18-Feb-99
1. For parenthesized subpatterns with repeats whose minimum was zero, the
computation of the store needed to hold the pattern was incorrect (too large).
If such patterns were nested a few deep, this could multiply and become a real
2. Added /M option to pcretest to show the memory requirement of a specific
pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
compiled in such a way that the backtracking after subsequent failure was
pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
Version 2.03 02-Feb-99
1. Fixed typo and small mistake in man page.
2. Added 4th condition (GPL supersedes if conflict) and created separate
LICENCE file containing the conditions.
3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
Perl, that is the internal \ allows the delimiter to be included in the
pattern. Locked out the use of \ as a delimiter. If \ immediately follows
the final delimiter, add \ to the end of the pattern (to test the error).
4. Added the convenience functions for extracting substrings after a successful
match. Updated pcretest to make it able to test these functions.
Version 2.02 14-Jan-99
1. Initialized the working variables associated with each extraction so that
their saving and restoring doesn't refer to uninitialized store.
2. Put dummy code into study.c in order to trick the optimizer of the IBM C
compiler for OS/2 into generating correct code. Apparently IBM isn't going to
fix the problem.
3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
calls, and wasn't printing the correct value for compiling calls. Increased the
default value of LOOPREPEAT, and the number of significant figures in the
4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
a building problem on Windows NT with a FAT file system.
Version 2.01 21-Oct-98
1. Changed the API for pcre_compile() to allow for the provision of a pointer
to character tables built by pcre_maketables() in the current locale. If NULL
is passed, the default tables are used.
Version 2.00 24-Sep-98
1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
it any more.
2. Allow quantification of (?>) groups, and make it work correctly.
3. The first character computation wasn't working for (?>) groups.
4. Correct the implementation of \Z (it is permitted to match on the \n at the
end of the subject) and add 5.005's \z, which really does match only at the
very end of the subject.
5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
localized options. All options to pcre_study() were also removed.
7. Add other new features from 5.005:
$(?<= positive lookbehind
$(?<! negative lookbehind
(?imsx-imsx) added the unsetting capability
such a setting is global if at outer level; local otherwise
(?imsx-imsx:) non-capturing groups with option setting
(?(cond)re|re) conditional pattern matching
A backreference to itself in a repeated group matches the previous
captured string.
8. General tidying up of studying (both automatic and via "study")
consequential on the addition of new assertions.
9. As in 5.005, unlimited repeated groups that could match an empty substring
are no longer faulted at compile time. Instead, the loop is forcibly broken at
runtime if any iteration does actually match an empty substring.
10. Include the RunTest script in the distribution.
11. Added tests from the Perl 5.005_02 distribution. This showed up a few
discrepancies, some of which were old and were also with respect to 5.004. They
have now been fixed.
Version 1.09 28-Apr-98
1. A negated single character class followed by a quantifier with a minimum
value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
program crashes, or just wrong answers. This did not apply to negated classes
containing more than one character, or to minima other than one.
Version 1.08 27-Mar-98
1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
latter must appear before anything that relies on it in the pattern.
Version 1.07 16-Feb-98
1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
repeat of a potentially empty string).
Version 1.06 23-Jan-98
1. Added Markus Oberhumer's little patches for C++.
2. Literal strings longer than 255 characters were broken.
Version 1.05 23-Dec-97
1. Negated character classes containing more than one character were failing if
PCRE_CASELESS was set at run time.
Version 1.04 19-Dec-97
1. Corrected the man page, where some "const" qualifiers had been omitted.
2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
input syntax.
3. Fixed memory leak which occurred when a regex with back references was
matched with an offsets vector that wasn't big enough. The temporary memory
that is used in this case wasn't being freed if the match failed.
4. Tidied pcretest to ensure it frees memory that it gets.
5. Temporary memory was being obtained in the case where the passed offsets
vector was exactly big enough.
6. Corrected definition of offsetof() from change 5 below.
7. I had screwed up change 6 below and broken the rules for the use of
setjmp(). Now fixed.
Version 1.03 18-Dec-97
1. A erroneous regex with a missing opening parenthesis was correctly
diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
on some systems.
2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
it was reported that one broken compiler failed on the former because "code" is
also an independent variable.
3. The erroneous regex a[]b caused an array overrun reference.
4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
fail on data ending with that character. (It was going on too far, and checking
the next character, typically a binary zero.) This was specific to the
optimized code for single-character negative classes.
5. Added a contributed patch from the TIN world which does the following:
+ Add an undef for memmove, in case the the system defines a macro for it.
+ Add a definition of offsetof(), in case there isn't one. (I don't know
the reason behind this - offsetof() is part of the ANSI standard - but
it does no harm).
+ Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
most of the places where whitespace preceded '#'. I have given up and
allowed the remaining 2 cases to be at the margin.
+ Rename some variables in pcre to eliminate shadowing. This seems very
pedantic, but does no harm, of course.
6. Moved the call to setjmp() into its own function, to get rid of warnings
from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
7. Constructs such as \d{8,} were compiling into the equivalent of
\d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
outcome, but in this particular case used more store than had been allocated,
which caused the bug to be discovered because it threw up an internal error.
8. The debugging code in both pcre and pcretest for outputting the compiled
form of a regex was going wrong in the case of back references followed by
curly-bracketed repeats.
Version 1.02 12-Dec-97
1. Typos in pcre.3 and comments in the source fixed.
2. Applied a contributed patch to get rid of places where it used to remove
'const' from variables, and fixed some signed/unsigned and uninitialized
variable warnings.
3. Added the "runtest" target to Makefile.
4. Set default compiler flag to -O2 rather than just -O.
Version 1.01 19-Nov-97
1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
like /([ab]*)*/, that is, for classes with more than one character in them.
2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
as /((?>a*))*/ (a PCRE_EXTRA facility).
Version 1.00 18-Nov-97
1. Added compile-time macros to support systems such as SunOS4 which don't have
memmove() or strerror() but have other things that can be used instead.
2. Arranged that "make clean" removes the executables.
Version 0.99 27-Oct-97
1. Fixed bug in code for optimizing classes with only one character. It was
initializing a 32-byte map regardless, which could cause it to run off the end
of the memory it had got.
2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
Version 0.98 22-Oct-97
1. Fixed bug in code for handling temporary memory usage when there are more
back references than supplied space in the ovector. This could cause segfaults.
Version 0.97 21-Oct-97
1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2. Optimized negated single characters not to use a bit map.
3. Brought error texts together as macro definitions; clarified some of them;
fixed one that was wrong - it said "range out of order" when it meant "invalid
escape sequence".
4. Changed some char * arguments to const char *.
6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
Version 0.96 16-Oct-97
1. Added a simple "pgrep" utility to the distribution.
2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
where "ddd" means "one or more decimal digits".
3. Fixed serious bug. If a pattern had a back reference, but the call to
pcre_exec() didn't supply a large enough ovector to record the related
identifying subpattern, the match always failed. PCRE now remembers the number
of the largest back reference, and gets some temporary memory in which to save
the offsets during matching if necessary, in order to ensure that
backreferences always work.
4. Increased the compatibility with Perl in a number of ways:
(a) . no longer matches \n by default; an option PCRE_DOTALL is provided
to request this handling. The option can be set at compile or exec time.
(b) $ matches before a terminating newline by default; an option
PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
mode). The option can be set at compile or exec time.
(c) The handling of \ followed by a digit other than 0 is now supposed to be
the same as Perl's. If the decimal number it represents is less than 10
or there aren't that many previous left capturing parentheses, an octal
escape is read. Inside a character class, it's always an octal escape,
even if it is a single digit.
(d) An escaped but undefined alphabetic character is taken as a literal,
unless PCRE_EXTRA is set. Currently this just reserves the remaining
(e) {0} is now permitted. (The previous item is removed from the compiled
5. Changed all the names of code files so that the basic parts are no longer
than 10 characters, and abolished the teeny "globals.c" file.
6. Changed the handling of character classes; they are now done with a 32-byte
bit map always.
7. Added the -d and /D options to pcretest to make it possible to look at the
internals of compilation without having to recompile pcre.
Version 0.95 23-Sep-97
1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
\x20 at the start of a run of normal characters. These were being treated as
real characters, instead of the source characters being re-checked.
Version 0.94 18-Sep-97
1. The functions are now thread-safe, with the caveat that the global variables
containing pointers to malloc() and free() or alternative functions are the
same for all threads.
2. Get pcre_study() to generate a bitmap of initial characters for non-
anchored patterns when this is possible, and use it if passed to pcre_exec().
Version 0.93 15-Sep-97
1. /(b)|(:+)/ was computing an incorrect first character.
2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
but not actually doing anything yet.
3. Treat "-" characters in classes that cannot be part of ranges as literals,
as Perl does (e.g. [-az] or [az-]).
4. Set the anchored flag if a branch starts with .* or .*? because that tests
all possible positions.
5. Split up into different modules to avoid including unneeded functions in a
compiled binary. However, compile and exec are still in one module. The "study"
function is split off.
6. The character tables are now in a separate module whose source is generated
by an auxiliary program - but can then be edited by hand if required. There are
now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
toupper() in the code.
7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
make them global. Abolish the function for setting them, as the caller can now
set them directly.
Version 0.92 11-Sep-97
1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
(e.g. /a{1,3}/) was broken (I mis-optimized it).
2. Caseless matching was not working in character classes if the characters in
the pattern were in upper case.
3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
4. Make PCRE_ANCHORED public and accept as a compile option.
5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
pass them.
6. Give an error if bad option bits passed at compile or run time.
7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
pcretest to cause it to pass that flag.
8. Add pcre_info(), to get the number of identifying subpatterns, the stored
options, and the first character, if set.
9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
Version 0.91 10-Sep-97
1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2. PCRE was looping on encountering an indefinitely repeated back reference to
a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
Perl does - treats the match as successful.