--- embedaddon/pcre/doc/pcrelimits.3 2012/02/21 23:05:52 1.1 +++ embedaddon/pcre/doc/pcrelimits.3 2014/06/15 19:46:04 1.1.1.5 @@ -1,4 +1,4 @@ -.TH PCRELIMITS 3 +.TH PCRELIMITS 3 "05 November 2013" "PCRE 8.34" .SH NAME PCRE - Perl-compatible regular expressions .SH "SIZE AND OTHER LIMITATIONS" @@ -7,21 +7,27 @@ PCRE - Perl-compatible regular expressions There are some size limitations in PCRE but it is hoped that they will never in practice be relevant. .P -The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE is -compiled with the default internal linkage size of 2. If you want to process -regular expressions that are truly enormous, you can compile PCRE with an -internal linkage size of 3 or 4 (see the \fBREADME\fP file in the source -distribution and the +The maximum length of a compiled pattern is approximately 64K data units (bytes +for the 8-bit library, 16-bit units for the 16-bit library, and 32-bit units for +the 32-bit library) if PCRE is compiled with the default internal linkage size, +which is 2 bytes for the 8-bit and 16-bit libraries, and 4 bytes for the 32-bit +library. If you want to process regular expressions that are truly enormous, +you can compile PCRE with an internal linkage size of 3 or 4 (when building the +16-bit or 32-bit library, 3 is rounded up to 4). See the \fBREADME\fP file in +the source distribution and the .\" HREF \fBpcrebuild\fP .\" -documentation for details). In these cases the limit is substantially larger. +documentation for details. In these cases the limit is substantially larger. However, the speed of execution is slower. .P All values in repeating quantifiers must be less than 65536. .P There is no limit to the number of parenthesized subpatterns, but there can be -no more than 65535 capturing subpatterns. +no more than 65535 capturing subpatterns. There is, however, a limit to the +depth of nesting of parenthesized subpatterns of all kinds. This is imposed in +order to limit the amount of system stack used at compile time. The limit can +be specified when PCRE is built; the default is 250. .P There is a limit to the number of forward references to subsequent subpatterns of around 200,000. Repeated forward references with fixed upper limits, for @@ -31,6 +37,9 @@ the count. There is no limit to the number of backward The maximum length of name for a named subpattern is 32 characters, and the maximum number of named subpatterns is 10000. .P +The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb +is 255 for the 8-bit library and 65535 for the 16-bit and 32-bit libraries. +.P The maximum length of a subject string is the largest positive number that an integer variable can hold. However, when using the traditional matching function, PCRE uses recursion to handle subpatterns and indefinite repetition. @@ -57,6 +66,6 @@ Cambridge CB2 3QH, England. .rs .sp .nf -Last updated: 30 November 2011 -Copyright (c) 1997-2011 University of Cambridge. +Last updated: 05 November 2013 +Copyright (c) 1997-2013 University of Cambridge. .fi