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1.1       misho       1: .TH PCRELIMITS 3
                      2: .SH NAME
                      3: PCRE - Perl-compatible regular expressions
                      4: .SH "SIZE AND OTHER LIMITATIONS"
                      5: .rs
                      6: .sp
                      7: There are some size limitations in PCRE but it is hoped that they will never in
                      8: practice be relevant.
                      9: .P
                     10: The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE is
                     11: compiled with the default internal linkage size of 2. If you want to process
                     12: regular expressions that are truly enormous, you can compile PCRE with an
                     13: internal linkage size of 3 or 4 (see the \fBREADME\fP file in the source
                     14: distribution and the
                     15: .\" HREF
                     16: \fBpcrebuild\fP
                     17: .\"
                     18: documentation for details). In these cases the limit is substantially larger.
                     19: However, the speed of execution is slower.
                     20: .P
                     21: All values in repeating quantifiers must be less than 65536.
                     22: .P
                     23: There is no limit to the number of parenthesized subpatterns, but there can be
                     24: no more than 65535 capturing subpatterns.
                     25: .P
                     26: There is a limit to the number of forward references to subsequent subpatterns
                     27: of around 200,000. Repeated forward references with fixed upper limits, for
                     28: example, (?2){0,100} when subpattern number 2 is to the right, are included in
                     29: the count. There is no limit to the number of backward references.
                     30: .P
                     31: The maximum length of name for a named subpattern is 32 characters, and the
                     32: maximum number of named subpatterns is 10000.
                     33: .P
                     34: The maximum length of a subject string is the largest positive number that an
                     35: integer variable can hold. However, when using the traditional matching
                     36: function, PCRE uses recursion to handle subpatterns and indefinite repetition.
                     37: This means that the available stack space may limit the size of a subject
                     38: string that can be processed by certain patterns. For a discussion of stack
                     39: issues, see the
                     40: .\" HREF
                     41: \fBpcrestack\fP
                     42: .\"
                     43: documentation.
                     44: .
                     45: .
                     46: .SH AUTHOR
                     47: .rs
                     48: .sp
                     49: .nf
                     50: Philip Hazel
                     51: University Computing Service
                     52: Cambridge CB2 3QH, England.
                     53: .fi
                     54: .
                     55: .
                     56: .SH REVISION
                     57: .rs
                     58: .sp
                     59: .nf
                     60: Last updated: 30 November 2011
                     61: Copyright (c) 1997-2011 University of Cambridge.
                     62: .fi