Annotation of embedaddon/pcre/doc/html/pcrelimits.html, revision 1.1
1.1 ! misho 1: <html>
! 2: <head>
! 3: <title>pcrelimits specification</title>
! 4: </head>
! 5: <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
! 6: <h1>pcrelimits man page</h1>
! 7: <p>
! 8: Return to the <a href="index.html">PCRE index page</a>.
! 9: </p>
! 10: <p>
! 11: This page is part of the PCRE HTML documentation. It was generated automatically
! 12: from the original man page. If there is any nonsense in it, please consult the
! 13: man page, in case the conversion went wrong.
! 14: <br>
! 15: <br><b>
! 16: SIZE AND OTHER LIMITATIONS
! 17: </b><br>
! 18: <P>
! 19: There are some size limitations in PCRE but it is hoped that they will never in
! 20: practice be relevant.
! 21: </P>
! 22: <P>
! 23: The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE is
! 24: compiled with the default internal linkage size of 2. If you want to process
! 25: regular expressions that are truly enormous, you can compile PCRE with an
! 26: internal linkage size of 3 or 4 (see the <b>README</b> file in the source
! 27: distribution and the
! 28: <a href="pcrebuild.html"><b>pcrebuild</b></a>
! 29: documentation for details). In these cases the limit is substantially larger.
! 30: However, the speed of execution is slower.
! 31: </P>
! 32: <P>
! 33: All values in repeating quantifiers must be less than 65536.
! 34: </P>
! 35: <P>
! 36: There is no limit to the number of parenthesized subpatterns, but there can be
! 37: no more than 65535 capturing subpatterns.
! 38: </P>
! 39: <P>
! 40: There is a limit to the number of forward references to subsequent subpatterns
! 41: of around 200,000. Repeated forward references with fixed upper limits, for
! 42: example, (?2){0,100} when subpattern number 2 is to the right, are included in
! 43: the count. There is no limit to the number of backward references.
! 44: </P>
! 45: <P>
! 46: The maximum length of name for a named subpattern is 32 characters, and the
! 47: maximum number of named subpatterns is 10000.
! 48: </P>
! 49: <P>
! 50: The maximum length of a subject string is the largest positive number that an
! 51: integer variable can hold. However, when using the traditional matching
! 52: function, PCRE uses recursion to handle subpatterns and indefinite repetition.
! 53: This means that the available stack space may limit the size of a subject
! 54: string that can be processed by certain patterns. For a discussion of stack
! 55: issues, see the
! 56: <a href="pcrestack.html"><b>pcrestack</b></a>
! 57: documentation.
! 58: </P>
! 59: <br><b>
! 60: AUTHOR
! 61: </b><br>
! 62: <P>
! 63: Philip Hazel
! 64: <br>
! 65: University Computing Service
! 66: <br>
! 67: Cambridge CB2 3QH, England.
! 68: <br>
! 69: </P>
! 70: <br><b>
! 71: REVISION
! 72: </b><br>
! 73: <P>
! 74: Last updated: 30 November 2011
! 75: <br>
! 76: Copyright © 1997-2011 University of Cambridge.
! 77: <br>
! 78: <p>
! 79: Return to the <a href="index.html">PCRE index page</a>.
! 80: </p>
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