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Diffstat (limited to 'ext/pcre/pcrelib/doc/pcre.txt')
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1 files changed, 451 insertions, 292 deletions
diff --git a/ext/pcre/pcrelib/doc/pcre.txt b/ext/pcre/pcrelib/doc/pcre.txt index 9c7884998c..f50b1d36d7 100644 --- a/ext/pcre/pcrelib/doc/pcre.txt +++ b/ext/pcre/pcrelib/doc/pcre.txt @@ -72,6 +72,7 @@ USER DOCUMENTATION of searching. The sections are as follows: pcre this document + pcre-config show PCRE installation configuration information pcreapi details of PCRE's native C API pcrebuild options for building PCRE pcrecallout details of the callout feature @@ -211,15 +212,18 @@ UTF-8 AND UNICODE PROPERTY SUPPORT AUTHOR Philip Hazel - University Computing Service, + University Computing Service Cambridge CB2 3QH, England. Putting an actual email address here seems to have been a spam magnet, - so I've taken it away. If you want to email me, use my initial and sur- - name, separated by a dot, at the domain ucs.cam.ac.uk. + so I've taken it away. If you want to email me, use my two initials, + followed by the two digits 10, at the domain cam.ac.uk. -Last updated: 23 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +REVISION + + Last updated: 18 April 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -241,12 +245,12 @@ PCRE BUILD-TIME OPTIONS ./configure --help - The following sections describe certain options whose names begin with - --enable or --disable. These settings specify changes to the defaults - for the configure command. Because of the way that configure works, - --enable and --disable always come in pairs, so the complementary - option always exists as well, but as it specifies the default, it is - not described. + The following sections include descriptions of options whose names + begin with --enable or --disable. These settings specify changes to the + defaults for the configure command. Because of the way that configure + works, --enable and --disable always come in pairs, so the complemen- + tary option always exists as well, but as it specifies the default, it + is not described. C++ SUPPORT @@ -285,22 +289,21 @@ UNICODE CHARACTER PROPERTY SUPPORT to the configure command. This implies UTF-8 support, even if you have not explicitly requested it. - Including Unicode property support adds around 90K of tables to the - PCRE library, approximately doubling its size. Only the general cate- - gory properties such as Lu and Nd are supported. Details are given in - the pcrepattern documentation. + Including Unicode property support adds around 30K of tables to the + PCRE library. Only the general category properties such as Lu and Nd + are supported. Details are given in the pcrepattern documentation. CODE VALUE OF NEWLINE - By default, PCRE interprets character 10 (linefeed, LF) as indicating - the end of a line. This is the normal newline character on Unix-like + By default, PCRE interprets character 10 (linefeed, LF) as indicating + the end of a line. This is the normal newline character on Unix-like systems. You can compile PCRE to use character 13 (carriage return, CR) instead, by adding --enable-newline-is-cr - to the configure command. There is also a --enable-newline-is-lf + to the configure command. There is also a --enable-newline-is-lf option, which explicitly specifies linefeed as the newline character. Alternatively, you can specify that line endings are to be indicated by @@ -310,19 +313,24 @@ CODE VALUE OF NEWLINE to the configure command. There is a fourth option, specified by + --enable-newline-is-anycrlf + + which causes PCRE to recognize any of the three sequences CR, LF, or + CRLF as indicating a line ending. Finally, a fifth option, specified by + --enable-newline-is-any - which causes PCRE to recognize any Unicode newline sequence. + causes PCRE to recognize any Unicode newline sequence. - Whatever line ending convention is selected when PCRE is built can be - overridden when the library functions are called. At build time it is + Whatever line ending convention is selected when PCRE is built can be + overridden when the library functions are called. At build time it is conventional to use the standard for your operating system. BUILDING SHARED AND STATIC LIBRARIES - The PCRE building process uses libtool to build both shared and static - Unix libraries by default. You can suppress one of these by adding one + The PCRE building process uses libtool to build both shared and static + Unix libraries by default. You can suppress one of these by adding one of --disable-shared @@ -334,9 +342,9 @@ BUILDING SHARED AND STATIC LIBRARIES POSIX MALLOC USAGE When PCRE is called through the POSIX interface (see the pcreposix doc- - umentation), additional working storage is required for holding the - pointers to capturing substrings, because PCRE requires three integers - per substring, whereas the POSIX interface provides only two. If the + umentation), additional working storage is required for holding the + pointers to capturing substrings, because PCRE requires three integers + per substring, whereas the POSIX interface provides only two. If the number of expected substrings is small, the wrapper function uses space on the stack, because this is faster than using malloc() for each call. The default threshold above which the stack is no longer used is 10; it @@ -349,26 +357,21 @@ POSIX MALLOC USAGE HANDLING VERY LARGE PATTERNS - Within a compiled pattern, offset values are used to point from one - part to another (for example, from an opening parenthesis to an alter- - nation metacharacter). By default, two-byte values are used for these - offsets, leading to a maximum size for a compiled pattern of around - 64K. This is sufficient to handle all but the most gigantic patterns. - Nevertheless, some people do want to process enormous patterns, so it - is possible to compile PCRE to use three-byte or four-byte offsets by + Within a compiled pattern, offset values are used to point from one + part to another (for example, from an opening parenthesis to an alter- + nation metacharacter). By default, two-byte values are used for these + offsets, leading to a maximum size for a compiled pattern of around + 64K. This is sufficient to handle all but the most gigantic patterns. + Nevertheless, some people do want to process enormous patterns, so it + is possible to compile PCRE to use three-byte or four-byte offsets by adding a setting such as --with-link-size=3 - to the configure command. The value given must be 2, 3, or 4. Using - longer offsets slows down the operation of PCRE because it has to load + to the configure command. The value given must be 2, 3, or 4. Using + longer offsets slows down the operation of PCRE because it has to load additional bytes when handling them. - If you build PCRE with an increased link size, test 2 (and test 5 if - you are using UTF-8) will fail. Part of the output of these tests is a - representation of the compiled pattern, and this changes with the link - size. - AVOIDING EXCESSIVE STACK USAGE @@ -426,24 +429,53 @@ LIMITING PCRE RESOURCE USAGE time. +CREATING CHARACTER TABLES AT BUILD TIME + + PCRE uses fixed tables for processing characters whose code values are + less than 256. By default, PCRE is built with a set of tables that are + distributed in the file pcre_chartables.c.dist. These tables are for + ASCII codes only. If you add + + --enable-rebuild-chartables + + to the configure command, the distributed tables are no longer used. + Instead, a program called dftables is compiled and run. This outputs + the source for new set of tables, created in the default locale of your + C runtime system. (This method of replacing the tables does not work if + you are cross compiling, because dftables is run on the local host. If + you need to create alternative tables when cross compiling, you will + have to do so "by hand".) + + USING EBCDIC CODE - PCRE assumes by default that it will run in an environment where the - character code is ASCII (or Unicode, which is a superset of ASCII). - PCRE can, however, be compiled to run in an EBCDIC environment by + PCRE assumes by default that it will run in an environment where the + character code is ASCII (or Unicode, which is a superset of ASCII). + PCRE can, however, be compiled to run in an EBCDIC environment by adding --enable-ebcdic - to the configure command. + to the configure command. This setting implies --enable-rebuild-charta- + bles. SEE ALSO pcreapi(3), pcre_config(3). -Last updated: 30 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 16 April 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -495,8 +527,8 @@ REGULAR EXPRESSIONS AS TREES THE STANDARD MATCHING ALGORITHM - In the terminology of Jeffrey Friedl's book Mastering Regular Expres- - sions, the standard algorithm is an "NFA algorithm". It conducts a + In the terminology of Jeffrey Friedl's book "Mastering Regular Expres- + sions", the standard algorithm is an "NFA algorithm". It conducts a depth-first search of the pattern tree. That is, it proceeds along a single path through the tree, checking that the subject matches what is required. When there is a mismatch, the algorithm tries any alterna- @@ -622,8 +654,18 @@ DISADVANTAGES OF THE ALTERNATIVE ALGORITHM 3. Although atomic groups are supported, their use does not provide the performance advantage that it does for the standard algorithm. -Last updated: 24 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -805,13 +847,13 @@ PCRE API OVERVIEW NEWLINES - PCRE supports four different conventions for indicating line breaks in + PCRE supports five different conventions for indicating line breaks in strings: a single CR (carriage return) character, a single LF (line- - feed) character, the two-character sequence CRLF, or any Unicode new- - line sequence. The Unicode newline sequences are the three just men- - tioned, plus the single characters VT (vertical tab, U+000B), FF (form- - feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), - and PS (paragraph separator, U+2029). + feed) character, the two-character sequence CRLF, any of the three pre- + ceding, or any Unicode newline sequence. The Unicode newline sequences + are the three just mentioned, plus the single characters VT (vertical + tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line + separator, U+2028), and PS (paragraph separator, U+2029). Each of the first three conventions is used by at least one operating system as its standard newline sequence. When PCRE is built, a default @@ -845,7 +887,9 @@ SAVING PRECOMPILED PATTERNS FOR LATER USE The compiled form of a regular expression can be saved and re-used at a later time, possibly by a different program, and even on a host other than the one on which it was compiled. Details are given in the - pcreprecompile documentation. + pcreprecompile documentation. However, compiling a regular expression + with one version of PCRE for use with a different version is not guar- + anteed to work and may cause crashes. CHECKING BUILD-TIME OPTIONS @@ -876,9 +920,9 @@ CHECKING BUILD-TIME OPTIONS The output is an integer whose value specifies the default character sequence that is recognized as meaning "newline". The four values that - are supported are: 10 for LF, 13 for CR, 3338 for CRLF, and -1 for ANY. - The default should normally be the standard sequence for your operating - system. + are supported are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, + and -1 for ANY. The default should normally be the standard sequence + for your operating system. PCRE_CONFIG_LINK_SIZE @@ -1102,26 +1146,29 @@ COMPILING A PATTERN PCRE_NEWLINE_CR PCRE_NEWLINE_LF PCRE_NEWLINE_CRLF + PCRE_NEWLINE_ANYCRLF PCRE_NEWLINE_ANY These options override the default newline definition that was chosen when PCRE was built. Setting the first or the second specifies that a newline is indicated by a single character (CR or LF, respectively). Setting PCRE_NEWLINE_CRLF specifies that a newline is indicated by the - two-character CRLF sequence. Setting PCRE_NEWLINE_ANY specifies that - any Unicode newline sequence should be recognized. The Unicode newline - sequences are the three just mentioned, plus the single characters VT - (vertical tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), - LS (line separator, U+2028), and PS (paragraph separator, U+2029). The - last two are recognized only in UTF-8 mode. + two-character CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies + that any of the three preceding sequences should be recognized. Setting + PCRE_NEWLINE_ANY specifies that any Unicode newline sequence should be + recognized. The Unicode newline sequences are the three just mentioned, + plus the single characters VT (vertical tab, U+000B), FF (formfeed, + U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS + (paragraph separator, U+2029). The last two are recognized only in + UTF-8 mode. The newline setting in the options word uses three bits that are - treated as a number, giving eight possibilities. Currently only five - are used (default plus the four values above). This means that if you - set more than one newline option, the combination may or may not be - sensible. For example, PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equiva- - lent to PCRE_NEWLINE_CRLF, but other combinations yield unused numbers - and cause an error. + treated as a number, giving eight possibilities. Currently only six are + used (default plus the five values above). This means that if you set + more than one newline option, the combination may or may not be sensi- + ble. For example, PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to + PCRE_NEWLINE_CRLF, but other combinations may yield unused numbers and + cause an error. The only time that a line break is specially recognized when compiling a pattern is if PCRE_EXTENDED is set, and an unescaped # outside a @@ -1287,31 +1334,41 @@ STUDYING A PATTERN LOCALE SUPPORT PCRE handles caseless matching, and determines whether characters are - letters digits, or whatever, by reference to a set of tables, indexed + letters, digits, or whatever, by reference to a set of tables, indexed by character value. When running in UTF-8 mode, this applies only to characters with codes less than 128. Higher-valued codes never match escapes such as \w or \d, but can be tested with \p if PCRE is built with Unicode character property support. The use of locales with Uni- - code is discouraged. - - An internal set of tables is created in the default C locale when PCRE - is built. This is used when the final argument of pcre_compile() is - NULL, and is sufficient for many applications. An alternative set of - tables can, however, be supplied. These may be created in a different - locale from the default. As more and more applications change to using - Unicode, the need for this locale support is expected to die away. - - External tables are built by calling the pcre_maketables() function, - which has no arguments, in the relevant locale. The result can then be - passed to pcre_compile() or pcre_exec() as often as necessary. For - example, to build and use tables that are appropriate for the French - locale (where accented characters with values greater than 128 are + code is discouraged. If you are handling characters with codes greater + than 128, you should either use UTF-8 and Unicode, or use locales, but + not try to mix the two. + + PCRE contains an internal set of tables that are used when the final + argument of pcre_compile() is NULL. These are sufficient for many + applications. Normally, the internal tables recognize only ASCII char- + acters. However, when PCRE is built, it is possible to cause the inter- + nal tables to be rebuilt in the default "C" locale of the local system, + which may cause them to be different. + + The internal tables can always be overridden by tables supplied by the + application that calls PCRE. These may be created in a different locale + from the default. As more and more applications change to using Uni- + code, the need for this locale support is expected to die away. + + External tables are built by calling the pcre_maketables() function, + which has no arguments, in the relevant locale. The result can then be + passed to pcre_compile() or pcre_exec() as often as necessary. For + example, to build and use tables that are appropriate for the French + locale (where accented characters with values greater than 128 are treated as letters), the following code could be used: setlocale(LC_CTYPE, "fr_FR"); tables = pcre_maketables(); re = pcre_compile(..., tables); + The locale name "fr_FR" is used on Linux and other Unix-like systems; + if you are using Windows, the name for the French locale is "french". + When pcre_maketables() runs, the tables are built in memory that is obtained via pcre_malloc. It is the caller's responsibility to ensure that the memory containing the tables remains available for as long as @@ -1679,6 +1736,7 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION PCRE_NEWLINE_CR PCRE_NEWLINE_LF PCRE_NEWLINE_CRLF + PCRE_NEWLINE_ANYCRLF PCRE_NEWLINE_ANY These options override the newline definition that was chosen or @@ -1686,190 +1744,191 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION tion of pcre_compile() above. During matching, the newline choice affects the behaviour of the dot, circumflex, and dollar metacharac- ters. It may also alter the way the match position is advanced after a - match failure for an unanchored pattern. When PCRE_NEWLINE_CRLF or - PCRE_NEWLINE_ANY is set, and a match attempt fails when the current - position is at a CRLF sequence, the match position is advanced by two - characters instead of one, in other words, to after the CRLF. + match failure for an unanchored pattern. When PCRE_NEWLINE_CRLF, + PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a match attempt + fails when the current position is at a CRLF sequence, the match posi- + tion is advanced by two characters instead of one, in other words, to + after the CRLF. PCRE_NOTBOL This option specifies that first character of the subject string is not - the beginning of a line, so the circumflex metacharacter should not - match before it. Setting this without PCRE_MULTILINE (at compile time) - causes circumflex never to match. This option affects only the behav- + the beginning of a line, so the circumflex metacharacter should not + match before it. Setting this without PCRE_MULTILINE (at compile time) + causes circumflex never to match. This option affects only the behav- iour of the circumflex metacharacter. It does not affect \A. PCRE_NOTEOL This option specifies that the end of the subject string is not the end - of a line, so the dollar metacharacter should not match it nor (except - in multiline mode) a newline immediately before it. Setting this with- + of a line, so the dollar metacharacter should not match it nor (except + in multiline mode) a newline immediately before it. Setting this with- out PCRE_MULTILINE (at compile time) causes dollar never to match. This - option affects only the behaviour of the dollar metacharacter. It does + option affects only the behaviour of the dollar metacharacter. It does not affect \Z or \z. PCRE_NOTEMPTY An empty string is not considered to be a valid match if this option is - set. If there are alternatives in the pattern, they are tried. If all - the alternatives match the empty string, the entire match fails. For + set. If there are alternatives in the pattern, they are tried. If all + the alternatives match the empty string, the entire match fails. For example, if the pattern a?b? - is applied to a string not beginning with "a" or "b", it matches the - empty string at the start of the subject. With PCRE_NOTEMPTY set, this + is applied to a string not beginning with "a" or "b", it matches the + empty string at the start of the subject. With PCRE_NOTEMPTY set, this match is not valid, so PCRE searches further into the string for occur- rences of "a" or "b". Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe- - cial case of a pattern match of the empty string within its split() - function, and when using the /g modifier. It is possible to emulate + cial case of a pattern match of the empty string within its split() + function, and when using the /g modifier. It is possible to emulate Perl's behaviour after matching a null string by first trying the match again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then - if that fails by advancing the starting offset (see below) and trying + if that fails by advancing the starting offset (see below) and trying an ordinary match again. There is some code that demonstrates how to do this in the pcredemo.c sample program. PCRE_NO_UTF8_CHECK When PCRE_UTF8 is set at compile time, the validity of the subject as a - UTF-8 string is automatically checked when pcre_exec() is subsequently - called. The value of startoffset is also checked to ensure that it - points to the start of a UTF-8 character. If an invalid UTF-8 sequence + UTF-8 string is automatically checked when pcre_exec() is subsequently + called. The value of startoffset is also checked to ensure that it + points to the start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found, pcre_exec() returns the error PCRE_ERROR_BADUTF8. If - startoffset contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is + startoffset contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned. - If you already know that your subject is valid, and you want to skip - these checks for performance reasons, you can set the - PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might want to - do this for the second and subsequent calls to pcre_exec() if you are - making repeated calls to find all the matches in a single subject - string. However, you should be sure that the value of startoffset - points to the start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is - set, the effect of passing an invalid UTF-8 string as a subject, or a - value of startoffset that does not point to the start of a UTF-8 char- + If you already know that your subject is valid, and you want to skip + these checks for performance reasons, you can set the + PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might want to + do this for the second and subsequent calls to pcre_exec() if you are + making repeated calls to find all the matches in a single subject + string. However, you should be sure that the value of startoffset + points to the start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is + set, the effect of passing an invalid UTF-8 string as a subject, or a + value of startoffset that does not point to the start of a UTF-8 char- acter, is undefined. Your program may crash. PCRE_PARTIAL - This option turns on the partial matching feature. If the subject - string fails to match the pattern, but at some point during the match- - ing process the end of the subject was reached (that is, the subject - partially matches the pattern and the failure to match occurred only - because there were not enough subject characters), pcre_exec() returns - PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is - used, there are restrictions on what may appear in the pattern. These + This option turns on the partial matching feature. If the subject + string fails to match the pattern, but at some point during the match- + ing process the end of the subject was reached (that is, the subject + partially matches the pattern and the failure to match occurred only + because there were not enough subject characters), pcre_exec() returns + PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is + used, there are restrictions on what may appear in the pattern. These are discussed in the pcrepartial documentation. The string to be matched by pcre_exec() - The subject string is passed to pcre_exec() as a pointer in subject, a - length in length, and a starting byte offset in startoffset. In UTF-8 - mode, the byte offset must point to the start of a UTF-8 character. - Unlike the pattern string, the subject may contain binary zero bytes. - When the starting offset is zero, the search for a match starts at the + The subject string is passed to pcre_exec() as a pointer in subject, a + length in length, and a starting byte offset in startoffset. In UTF-8 + mode, the byte offset must point to the start of a UTF-8 character. + Unlike the pattern string, the subject may contain binary zero bytes. + When the starting offset is zero, the search for a match starts at the beginning of the subject, and this is by far the most common case. - A non-zero starting offset is useful when searching for another match - in the same subject by calling pcre_exec() again after a previous suc- - cess. Setting startoffset differs from just passing over a shortened - string and setting PCRE_NOTBOL in the case of a pattern that begins + A non-zero starting offset is useful when searching for another match + in the same subject by calling pcre_exec() again after a previous suc- + cess. Setting startoffset differs from just passing over a shortened + string and setting PCRE_NOTBOL in the case of a pattern that begins with any kind of lookbehind. For example, consider the pattern \Biss\B - which finds occurrences of "iss" in the middle of words. (\B matches - only if the current position in the subject is not a word boundary.) - When applied to the string "Mississipi" the first call to pcre_exec() - finds the first occurrence. If pcre_exec() is called again with just - the remainder of the subject, namely "issipi", it does not match, + which finds occurrences of "iss" in the middle of words. (\B matches + only if the current position in the subject is not a word boundary.) + When applied to the string "Mississipi" the first call to pcre_exec() + finds the first occurrence. If pcre_exec() is called again with just + the remainder of the subject, namely "issipi", it does not match, because \B is always false at the start of the subject, which is deemed - to be a word boundary. However, if pcre_exec() is passed the entire + to be a word boundary. However, if pcre_exec() is passed the entire string again, but with startoffset set to 4, it finds the second occur- - rence of "iss" because it is able to look behind the starting point to + rence of "iss" because it is able to look behind the starting point to discover that it is preceded by a letter. - If a non-zero starting offset is passed when the pattern is anchored, + If a non-zero starting offset is passed when the pattern is anchored, one attempt to match at the given offset is made. This can only succeed - if the pattern does not require the match to be at the start of the + if the pattern does not require the match to be at the start of the subject. How pcre_exec() returns captured substrings - In general, a pattern matches a certain portion of the subject, and in - addition, further substrings from the subject may be picked out by - parts of the pattern. Following the usage in Jeffrey Friedl's book, - this is called "capturing" in what follows, and the phrase "capturing - subpattern" is used for a fragment of a pattern that picks out a sub- - string. PCRE supports several other kinds of parenthesized subpattern + In general, a pattern matches a certain portion of the subject, and in + addition, further substrings from the subject may be picked out by + parts of the pattern. Following the usage in Jeffrey Friedl's book, + this is called "capturing" in what follows, and the phrase "capturing + subpattern" is used for a fragment of a pattern that picks out a sub- + string. PCRE supports several other kinds of parenthesized subpattern that do not cause substrings to be captured. - Captured substrings are returned to the caller via a vector of integer - offsets whose address is passed in ovector. The number of elements in - the vector is passed in ovecsize, which must be a non-negative number. + Captured substrings are returned to the caller via a vector of integer + offsets whose address is passed in ovector. The number of elements in + the vector is passed in ovecsize, which must be a non-negative number. Note: this argument is NOT the size of ovector in bytes. - The first two-thirds of the vector is used to pass back captured sub- - strings, each substring using a pair of integers. The remaining third - of the vector is used as workspace by pcre_exec() while matching cap- - turing subpatterns, and is not available for passing back information. - The length passed in ovecsize should always be a multiple of three. If + The first two-thirds of the vector is used to pass back captured sub- + strings, each substring using a pair of integers. The remaining third + of the vector is used as workspace by pcre_exec() while matching cap- + turing subpatterns, and is not available for passing back information. + The length passed in ovecsize should always be a multiple of three. If it is not, it is rounded down. - When a match is successful, information about captured substrings is - returned in pairs of integers, starting at the beginning of ovector, - and continuing up to two-thirds of its length at the most. The first + When a match is successful, information about captured substrings is + returned in pairs of integers, starting at the beginning of ovector, + and continuing up to two-thirds of its length at the most. The first element of a pair is set to the offset of the first character in a sub- - string, and the second is set to the offset of the first character - after the end of a substring. The first pair, ovector[0] and ovec- - tor[1], identify the portion of the subject string matched by the - entire pattern. The next pair is used for the first capturing subpat- + string, and the second is set to the offset of the first character + after the end of a substring. The first pair, ovector[0] and ovec- + tor[1], identify the portion of the subject string matched by the + entire pattern. The next pair is used for the first capturing subpat- tern, and so on. The value returned by pcre_exec() is one more than the highest numbered pair that has been set. For example, if two substrings - have been captured, the returned value is 3. If there are no capturing - subpatterns, the return value from a successful match is 1, indicating + have been captured, the returned value is 3. If there are no capturing + subpatterns, the return value from a successful match is 1, indicating that just the first pair of offsets has been set. If a capturing subpattern is matched repeatedly, it is the last portion of the string that it matched that is returned. - If the vector is too small to hold all the captured substring offsets, + If the vector is too small to hold all the captured substring offsets, it is used as far as possible (up to two-thirds of its length), and the - function returns a value of zero. In particular, if the substring off- + function returns a value of zero. In particular, if the substring off- sets are not of interest, pcre_exec() may be called with ovector passed - as NULL and ovecsize as zero. However, if the pattern contains back - references and the ovector is not big enough to remember the related - substrings, PCRE has to get additional memory for use during matching. + as NULL and ovecsize as zero. However, if the pattern contains back + references and the ovector is not big enough to remember the related + substrings, PCRE has to get additional memory for use during matching. Thus it is usually advisable to supply an ovector. - The pcre_info() function can be used to find out how many capturing - subpatterns there are in a compiled pattern. The smallest size for - ovector that will allow for n captured substrings, in addition to the + The pcre_info() function can be used to find out how many capturing + subpatterns there are in a compiled pattern. The smallest size for + ovector that will allow for n captured substrings, in addition to the offsets of the substring matched by the whole pattern, is (n+1)*3. - It is possible for capturing subpattern number n+1 to match some part + It is possible for capturing subpattern number n+1 to match some part of the subject when subpattern n has not been used at all. For example, - if the string "abc" is matched against the pattern (a|(z))(bc) the + if the string "abc" is matched against the pattern (a|(z))(bc) the return from the function is 4, and subpatterns 1 and 3 are matched, but - 2 is not. When this happens, both values in the offset pairs corre- + 2 is not. When this happens, both values in the offset pairs corre- sponding to unused subpatterns are set to -1. - Offset values that correspond to unused subpatterns at the end of the - expression are also set to -1. For example, if the string "abc" is - matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not - matched. The return from the function is 2, because the highest used + Offset values that correspond to unused subpatterns at the end of the + expression are also set to -1. For example, if the string "abc" is + matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not + matched. The return from the function is 2, because the highest used capturing subpattern number is 1. However, you can refer to the offsets - for the second and third capturing subpatterns if you wish (assuming + for the second and third capturing subpatterns if you wish (assuming the vector is large enough, of course). - Some convenience functions are provided for extracting the captured + Some convenience functions are provided for extracting the captured substrings as separate strings. These are described below. Error return values from pcre_exec() - If pcre_exec() fails, it returns a negative number. The following are + If pcre_exec() fails, it returns a negative number. The following are defined in the header file: PCRE_ERROR_NOMATCH (-1) @@ -1878,7 +1937,7 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION PCRE_ERROR_NULL (-2) - Either code or subject was passed as NULL, or ovector was NULL and + Either code or subject was passed as NULL, or ovector was NULL and ovecsize was not zero. PCRE_ERROR_BADOPTION (-3) @@ -1887,87 +1946,87 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION PCRE_ERROR_BADMAGIC (-4) - PCRE stores a 4-byte "magic number" at the start of the compiled code, + PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch the case when it is passed a junk pointer and to detect when a pattern that was compiled in an environment of one endianness is run in - an environment with the other endianness. This is the error that PCRE + an environment with the other endianness. This is the error that PCRE gives when the magic number is not present. PCRE_ERROR_UNKNOWN_OPCODE (-5) While running the pattern match, an unknown item was encountered in the - compiled pattern. This error could be caused by a bug in PCRE or by + compiled pattern. This error could be caused by a bug in PCRE or by overwriting of the compiled pattern. PCRE_ERROR_NOMEMORY (-6) - If a pattern contains back references, but the ovector that is passed + If a pattern contains back references, but the ovector that is passed to pcre_exec() is not big enough to remember the referenced substrings, - PCRE gets a block of memory at the start of matching to use for this - purpose. If the call via pcre_malloc() fails, this error is given. The + PCRE gets a block of memory at the start of matching to use for this + purpose. If the call via pcre_malloc() fails, this error is given. The memory is automatically freed at the end of matching. PCRE_ERROR_NOSUBSTRING (-7) - This error is used by the pcre_copy_substring(), pcre_get_substring(), + This error is used by the pcre_copy_substring(), pcre_get_substring(), and pcre_get_substring_list() functions (see below). It is never returned by pcre_exec(). PCRE_ERROR_MATCHLIMIT (-8) - The backtracking limit, as specified by the match_limit field in a - pcre_extra structure (or defaulted) was reached. See the description + The backtracking limit, as specified by the match_limit field in a + pcre_extra structure (or defaulted) was reached. See the description above. PCRE_ERROR_CALLOUT (-9) This error is never generated by pcre_exec() itself. It is provided for - use by callout functions that want to yield a distinctive error code. + use by callout functions that want to yield a distinctive error code. See the pcrecallout documentation for details. PCRE_ERROR_BADUTF8 (-10) - A string that contains an invalid UTF-8 byte sequence was passed as a + A string that contains an invalid UTF-8 byte sequence was passed as a subject. PCRE_ERROR_BADUTF8_OFFSET (-11) The UTF-8 byte sequence that was passed as a subject was valid, but the - value of startoffset did not point to the beginning of a UTF-8 charac- + value of startoffset did not point to the beginning of a UTF-8 charac- ter. PCRE_ERROR_PARTIAL (-12) - The subject string did not match, but it did match partially. See the + The subject string did not match, but it did match partially. See the pcrepartial documentation for details of partial matching. PCRE_ERROR_BADPARTIAL (-13) - The PCRE_PARTIAL option was used with a compiled pattern containing - items that are not supported for partial matching. See the pcrepartial + The PCRE_PARTIAL option was used with a compiled pattern containing + items that are not supported for partial matching. See the pcrepartial documentation for details of partial matching. PCRE_ERROR_INTERNAL (-14) - An unexpected internal error has occurred. This error could be caused + An unexpected internal error has occurred. This error could be caused by a bug in PCRE or by overwriting of the compiled pattern. PCRE_ERROR_BADCOUNT (-15) - This error is given if the value of the ovecsize argument is negative. + This error is given if the value of the ovecsize argument is negative. PCRE_ERROR_RECURSIONLIMIT (-21) The internal recursion limit, as specified by the match_limit_recursion - field in a pcre_extra structure (or defaulted) was reached. See the + field in a pcre_extra structure (or defaulted) was reached. See the description above. PCRE_ERROR_NULLWSLIMIT (-22) - When a group that can match an empty substring is repeated with an - unbounded upper limit, the subject position at the start of the group + When a group that can match an empty substring is repeated with an + unbounded upper limit, the subject position at the start of the group must be remembered, so that a test for an empty string can be made when - the end of the group is reached. Some workspace is required for this; + the end of the group is reached. Some workspace is required for this; if it runs out, this error is given. PCRE_ERROR_BADNEWLINE (-23) @@ -1990,78 +2049,78 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER int pcre_get_substring_list(const char *subject, int *ovector, int stringcount, const char ***listptr); - Captured substrings can be accessed directly by using the offsets - returned by pcre_exec() in ovector. For convenience, the functions + Captured substrings can be accessed directly by using the offsets + returned by pcre_exec() in ovector. For convenience, the functions pcre_copy_substring(), pcre_get_substring(), and pcre_get_sub- - string_list() are provided for extracting captured substrings as new, - separate, zero-terminated strings. These functions identify substrings - by number. The next section describes functions for extracting named + string_list() are provided for extracting captured substrings as new, + separate, zero-terminated strings. These functions identify substrings + by number. The next section describes functions for extracting named substrings. - A substring that contains a binary zero is correctly extracted and has - a further zero added on the end, but the result is not, of course, a C - string. However, you can process such a string by referring to the - length that is returned by pcre_copy_substring() and pcre_get_sub- + A substring that contains a binary zero is correctly extracted and has + a further zero added on the end, but the result is not, of course, a C + string. However, you can process such a string by referring to the + length that is returned by pcre_copy_substring() and pcre_get_sub- string(). Unfortunately, the interface to pcre_get_substring_list() is - not adequate for handling strings containing binary zeros, because the + not adequate for handling strings containing binary zeros, because the end of the final string is not independently indicated. - The first three arguments are the same for all three of these func- - tions: subject is the subject string that has just been successfully + The first three arguments are the same for all three of these func- + tions: subject is the subject string that has just been successfully matched, ovector is a pointer to the vector of integer offsets that was passed to pcre_exec(), and stringcount is the number of substrings that - were captured by the match, including the substring that matched the + were captured by the match, including the substring that matched the entire regular expression. This is the value returned by pcre_exec() if - it is greater than zero. If pcre_exec() returned zero, indicating that - it ran out of space in ovector, the value passed as stringcount should + it is greater than zero. If pcre_exec() returned zero, indicating that + it ran out of space in ovector, the value passed as stringcount should be the number of elements in the vector divided by three. - The functions pcre_copy_substring() and pcre_get_substring() extract a - single substring, whose number is given as stringnumber. A value of - zero extracts the substring that matched the entire pattern, whereas - higher values extract the captured substrings. For pcre_copy_sub- - string(), the string is placed in buffer, whose length is given by - buffersize, while for pcre_get_substring() a new block of memory is - obtained via pcre_malloc, and its address is returned via stringptr. - The yield of the function is the length of the string, not including + The functions pcre_copy_substring() and pcre_get_substring() extract a + single substring, whose number is given as stringnumber. A value of + zero extracts the substring that matched the entire pattern, whereas + higher values extract the captured substrings. For pcre_copy_sub- + string(), the string is placed in buffer, whose length is given by + buffersize, while for pcre_get_substring() a new block of memory is + obtained via pcre_malloc, and its address is returned via stringptr. + The yield of the function is the length of the string, not including the terminating zero, or one of these error codes: PCRE_ERROR_NOMEMORY (-6) - The buffer was too small for pcre_copy_substring(), or the attempt to + The buffer was too small for pcre_copy_substring(), or the attempt to get memory failed for pcre_get_substring(). PCRE_ERROR_NOSUBSTRING (-7) There is no substring whose number is stringnumber. - The pcre_get_substring_list() function extracts all available sub- - strings and builds a list of pointers to them. All this is done in a + The pcre_get_substring_list() function extracts all available sub- + strings and builds a list of pointers to them. All this is done in a single block of memory that is obtained via pcre_malloc. The address of - the memory block is returned via listptr, which is also the start of - the list of string pointers. The end of the list is marked by a NULL - pointer. The yield of the function is zero if all went well, or the + the memory block is returned via listptr, which is also the start of + the list of string pointers. The end of the list is marked by a NULL + pointer. The yield of the function is zero if all went well, or the error code PCRE_ERROR_NOMEMORY (-6) if the attempt to get the memory block failed. - When any of these functions encounter a substring that is unset, which - can happen when capturing subpattern number n+1 matches some part of - the subject, but subpattern n has not been used at all, they return an + When any of these functions encounter a substring that is unset, which + can happen when capturing subpattern number n+1 matches some part of + the subject, but subpattern n has not been used at all, they return an empty string. This can be distinguished from a genuine zero-length sub- - string by inspecting the appropriate offset in ovector, which is nega- + string by inspecting the appropriate offset in ovector, which is nega- tive for unset substrings. - The two convenience functions pcre_free_substring() and pcre_free_sub- - string_list() can be used to free the memory returned by a previous + The two convenience functions pcre_free_substring() and pcre_free_sub- + string_list() can be used to free the memory returned by a previous call of pcre_get_substring() or pcre_get_substring_list(), respec- - tively. They do nothing more than call the function pointed to by - pcre_free, which of course could be called directly from a C program. - However, PCRE is used in some situations where it is linked via a spe- - cial interface to another programming language that cannot use - pcre_free directly; it is for these cases that the functions are pro- + tively. They do nothing more than call the function pointed to by + pcre_free, which of course could be called directly from a C program. + However, PCRE is used in some situations where it is linked via a spe- + cial interface to another programming language that cannot use + pcre_free directly; it is for these cases that the functions are pro- vided. @@ -2080,7 +2139,7 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME int stringcount, const char *stringname, const char **stringptr); - To extract a substring by name, you first have to find associated num- + To extract a substring by name, you first have to find associated num- ber. For example, for this pattern (a+)b(?<xxx>\d+)... @@ -2089,27 +2148,28 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME be unique (PCRE_DUPNAMES was not set), you can find the number from the name by calling pcre_get_stringnumber(). The first argument is the com- piled pattern, and the second is the name. The yield of the function is - the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no + the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of that name. Given the number, you can extract the substring directly, or use one of the functions described in the previous section. For convenience, there are also two functions that do the whole job. - Most of the arguments of pcre_copy_named_substring() and - pcre_get_named_substring() are the same as those for the similarly - named functions that extract by number. As these are described in the - previous section, they are not re-described here. There are just two + Most of the arguments of pcre_copy_named_substring() and + pcre_get_named_substring() are the same as those for the similarly + named functions that extract by number. As these are described in the + previous section, they are not re-described here. There are just two differences: - First, instead of a substring number, a substring name is given. Sec- + First, instead of a substring number, a substring name is given. Sec- ond, there is an extra argument, given at the start, which is a pointer - to the compiled pattern. This is needed in order to gain access to the + to the compiled pattern. This is needed in order to gain access to the name-to-number translation table. - These functions call pcre_get_stringnumber(), and if it succeeds, they - then call pcre_copy_substring() or pcre_get_substring(), as appropri- - ate. + These functions call pcre_get_stringnumber(), and if it succeeds, they + then call pcre_copy_substring() or pcre_get_substring(), as appropri- + ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate names, the + behaviour may not be what you want (see the next section). DUPLICATE SUBPATTERN NAMES @@ -2318,8 +2378,18 @@ SEE ALSO pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar- tial(3), pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3). -Last updated: 30 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 24 April 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -2346,7 +2416,7 @@ PCRE CALLOUTS default value is zero. For example, this pattern has two callout points: - (?C1)eabc(?C2)def + (?C1)abc(?C2)def If the PCRE_AUTO_CALLOUT option bit is set when pcre_compile() is called, PCRE automatically inserts callouts, all with number 255, @@ -2477,8 +2547,18 @@ RETURN VALUES reserved for use by callout functions; it will never be used by PCRE itself. -Last updated: 28 February 2005 -Copyright (c) 1997-2005 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -2595,8 +2675,18 @@ DIFFERENCES BETWEEN PCRE AND PERL (j) The alternative matching function (pcre_dfa_exec()) matches in a different way and is not Perl-compatible. -Last updated: 28 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -2851,9 +2941,9 @@ BACKSLASH is a letter or digit. The definition of letters and digits is con- trolled by PCRE's low-valued character tables, and may vary if locale- specific matching is taking place (see "Locale support" in the pcreapi - page). For example, in the "fr_FR" (French) locale, some character - codes greater than 128 are used for accented letters, and these are - matched by \w. + page). For example, in a French locale such as "fr_FR" in Unix-like + systems, or "french" in Windows, some character codes greater than 128 + are used for accented letters, and these are matched by \w. In UTF-8 mode, characters with values greater than 128 never match \d, \s, or \w, and always match \D, \S, and \W. This is true even when Uni- @@ -3222,7 +3312,7 @@ SQUARE BRACKETS AND CHARACTER CLASSES If a range that includes letters is used when caseless matching is set, it matches the letters in either case. For example, [W-c] is equivalent to [][\\^_`wxyzabc], matched caselessly, and in non-UTF-8 mode, if - character tables for the "fr_FR" locale are in use, [\xc8-\xcb] matches + character tables for a French locale are in use, [\xc8-\xcb] matches accented E characters in both cases. In UTF-8 mode, PCRE supports the concept of case for characters with values greater than 128 only when it is compiled with Unicode property support. @@ -4271,8 +4361,18 @@ SEE ALSO pcreapi(3), pcrecallout(3), pcrematching(3), pcre(3). -Last updated: 06 December 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -4380,7 +4480,7 @@ EXAMPLE OF PARTIAL MATCHING USING PCRETEST using pcre_dfa_exec() matching (by means of the \D escape sequence), produces the following output: - re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/ + re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ data> 25jun04\P\D 0: 25jun04 data> 23dec3\P\D @@ -4407,7 +4507,7 @@ MULTI-SEGMENT MATCHING WITH pcre_dfa_exec() using the \R escape sequence to set the PCRE_DFA_RESTART option (\P and \D are as above): - re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/ + re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ data> 23ja\P\D Partial match: 23ja data> n05\R\D @@ -4440,10 +4540,9 @@ MULTI-SEGMENT MATCHING WITH pcre_dfa_exec() not always produce exactly the same result as matching over one single long string. The difference arises when there are multiple matching possibilities, because a partial match result is given only when there - are no completed matches in a call to fBpcre_dfa_exec(). This means - that as soon as the shortest match has been found, continuation to a - new subject segment is no longer possible. Consider this pcretest - example: + are no completed matches in a call to pcre_dfa_exec(). This means that + as soon as the shortest match has been found, continuation to a new + subject segment is no longer possible. Consider this pcretest example: re> /dog(sbody)?/ data> do\P\D @@ -4482,8 +4581,18 @@ MULTI-SEGMENT MATCHING WITH pcre_dfa_exec() where no string can be a partial match for both alternatives. -Last updated: 30 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -4507,7 +4616,9 @@ SAVING AND RE-USING PRECOMPILED PCRE PATTERNS ent host and run them there. This works even if the new host has the opposite endianness to the one on which the patterns were compiled. There may be a small performance penalty, but it should be insignifi- - cant. + cant. However, compiling regular expressions with one version of PCRE + for use with a different version is not guaranteed to work and may + cause crashes. SAVING A COMPILED PATTERN @@ -4604,8 +4715,18 @@ COMPATIBILITY WITH DIFFERENT PCRE RELEASES 7.0 or higher, because there was an internal reorganization at that release. -Last updated: 28 November 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 24 April 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -4744,8 +4865,18 @@ PROCESSING TIME In many cases, the solution to this kind of performance issue is to use an atomic group or a possessive quantifier. -Last updated: 20 September 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -4958,11 +5089,14 @@ MEMORY USAGE AUTHOR Philip Hazel - University Computing Service, + University Computing Service Cambridge CB2 3QH, England. -Last updated: 16 January 2006 -Copyright (c) 1997-2006 University of Cambridge. + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ @@ -5059,7 +5193,7 @@ MATCHING INTERFACE return false (because the empty string is not a valid number): int number; - pcrecpp::RE::FullMatch("abc", "[a-z]+(\d+)?", &number); + pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number); The matching interface supports at most 16 arguments per call. If you need more, consider using the more general interface @@ -5293,7 +5427,12 @@ REPLACING PARTS OF STRINGS AUTHOR The C++ wrapper was contributed by Google Inc. - Copyright (c) 2006 Google Inc. + Copyright (c) 2007 Google Inc. + + +REVISION + + Last updated: 06 March 2007 ------------------------------------------------------------------------------ @@ -5360,8 +5499,18 @@ PCRE SAMPLE PROGRAM (for example) to the compile command to get round this problem. -Last updated: 09 September 2004 -Copyright (c) 1997-2004 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 06 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ PCRESTACK(3) PCRESTACK(3) @@ -5414,7 +5563,7 @@ PCRE DISCUSSION OF STACK USAGE ter. For a long string, a lot of stack is required. Consider now this rewritten pattern, which matches exactly the same strings: - ([^<]++|<(?!inet)) + ([^<]++|<(?!inet))+ This uses very much less stack, because runs of characters that do not contain "<" are "swallowed" in one item inside the parentheses. Recur- @@ -5466,8 +5615,18 @@ PCRE DISCUSSION OF STACK USAGE has a command line option (-S) that can be used to increase the size of its stack. -Last updated: 14 September 2006 -Copyright (c) 1997-2006 University of Cambridge. + +AUTHOR + + Philip Hazel + University Computing Service + Cambridge CB2 3QH, England. + + +REVISION + + Last updated: 12 March 2007 + Copyright (c) 1997-2007 University of Cambridge. ------------------------------------------------------------------------------ |