/[pcre]/code/trunk/doc/pcrebuild.3
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revision 63 by nigel, Sat Feb 24 21:40:03 2007 UTC revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC
# Line 106  If you build PCRE with an increased link Line 106  If you build PCRE with an increased link
106  using UTF-8) will fail. Part of the output of these tests is a representation  using UTF-8) will fail. Part of the output of these tests is a representation
107  of the compiled pattern, and this changes with the link size.  of the compiled pattern, and this changes with the link size.
108    
109    .SH AVOIDING EXCESSIVE STACK USAGE
110    .rs
111    .sp
112    PCRE implements backtracking while matching by making recursive calls to an
113    internal function called \fBmatch()\fR. In environments where the size of the
114    stack is limited, this can severely limit PCRE's operation. (The Unix
115    environment does not usually suffer from this problem.) An alternative approach
116    that uses memory from the heap to remember data, instead of using recursive
117    function calls, has been implemented to work round this problem. If you want to
118    build a version of PCRE that works this way, add
119    
120      --disable-stack-for-recursion
121    
122    to the \fBconfigure\fR command. With this configuration, PCRE will use the
123    \fBpcre_stack_malloc\fR and \fBpcre_stack_free\fR variables to call memory
124    management functions. Separate functions are provided because the usage is very
125    predictable: the block sizes requested are always the same, and the blocks are
126    always freed in reverse order. A calling program might be able to implement
127    optimized functions that perform better than the standard \fBmalloc()\fR and
128    \fBfree()\fR functions. PCRE runs noticeably more slowly when built in this
129    way.
130    
131    .SH USING EBCDIC CODE
132    .rs
133    .sp
134    PCRE assumes by default that it will run in an environment where the character
135    code is ASCII (or UTF-8, which is a superset of ASCII). PCRE can, however, be
136    compiled to run in an EBCDIC environment by adding
137    
138      --enable-ebcdic
139    
140    to the \fBconfigure\fR command.
141    
142  .in 0  .in 0
143  Last updated: 21 January 2003  Last updated: 09 December 2003
144  .br  .br
145  Copyright (c) 1997-2003 University of Cambridge.  Copyright (c) 1997-2003 University of Cambridge.

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