[BACK]Return to pcrelimits.html CVS log [TXT] [DIR] Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / pcre / doc / html

Annotation of embedaddon/pcre/doc/html/pcrelimits.html, revision 1.1.1.5

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>
1.1.1.2   misho      23: The maximum length of a compiled pattern is approximately 64K data units (bytes
1.1.1.5 ! misho      24: for the 8-bit library, 16-bit units for the 16-bit library, and 32-bit units for
        !            25: the 32-bit library) if PCRE is compiled with the default internal linkage size,
        !            26: which is 2 bytes for the 8-bit and 16-bit libraries, and 4 bytes for the 32-bit
        !            27: library. If you want to process regular expressions that are truly enormous,
1.1.1.4   misho      28: you can compile PCRE with an internal linkage size of 3 or 4 (when building the
                     29: 16-bit or 32-bit library, 3 is rounded up to 4). See the <b>README</b> file in
                     30: the source distribution and the
1.1       misho      31: <a href="pcrebuild.html"><b>pcrebuild</b></a>
1.1.1.2   misho      32: documentation for details. In these cases the limit is substantially larger.
1.1       misho      33: However, the speed of execution is slower.
                     34: </P>
                     35: <P>
                     36: All values in repeating quantifiers must be less than 65536.
                     37: </P>
                     38: <P>
                     39: There is no limit to the number of parenthesized subpatterns, but there can be
1.1.1.5 ! misho      40: no more than 65535 capturing subpatterns. There is, however, a limit to the
        !            41: depth of nesting of parenthesized subpatterns of all kinds. This is imposed in
        !            42: order to limit the amount of system stack used at compile time. The limit can
        !            43: be specified when PCRE is built; the default is 250.
1.1       misho      44: </P>
                     45: <P>
                     46: There is a limit to the number of forward references to subsequent subpatterns
                     47: of around 200,000. Repeated forward references with fixed upper limits, for
                     48: example, (?2){0,100} when subpattern number 2 is to the right, are included in
                     49: the count. There is no limit to the number of backward references.
                     50: </P>
                     51: <P>
                     52: The maximum length of name for a named subpattern is 32 characters, and the
                     53: maximum number of named subpatterns is 10000.
                     54: </P>
                     55: <P>
1.1.1.3   misho      56: The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb
1.1.1.5 ! misho      57: is 255 for the 8-bit library and 65535 for the 16-bit and 32-bit libraries.
1.1.1.3   misho      58: </P>
                     59: <P>
1.1       misho      60: The maximum length of a subject string is the largest positive number that an
                     61: integer variable can hold. However, when using the traditional matching
                     62: function, PCRE uses recursion to handle subpatterns and indefinite repetition.
                     63: This means that the available stack space may limit the size of a subject
                     64: string that can be processed by certain patterns. For a discussion of stack
                     65: issues, see the
                     66: <a href="pcrestack.html"><b>pcrestack</b></a>
                     67: documentation.
                     68: </P>
                     69: <br><b>
                     70: AUTHOR
                     71: </b><br>
                     72: <P>
                     73: Philip Hazel
                     74: <br>
                     75: University Computing Service
                     76: <br>
                     77: Cambridge CB2 3QH, England.
                     78: <br>
                     79: </P>
                     80: <br><b>
                     81: REVISION
                     82: </b><br>
                     83: <P>
1.1.1.5 ! misho      84: Last updated: 05 November 2013
1.1       misho      85: <br>
1.1.1.5 ! misho      86: Copyright &copy; 1997-2013 University of Cambridge.
1.1       misho      87: <br>
                     88: <p>
                     89: Return to the <a href="index.html">PCRE index page</a>.
                     90: </p>
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>