/[pcre]/code/trunk/doc/html/pcrebuild.html

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-revision 76 by nigel,
Sat Feb 24 21:40:37 2007 UTC
+revision 77 by nigel,
Sat Feb 24 21:40:45 2007 UTC
 Line 113 
 to the configure command.
  <br><a name="SEC7" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br>
  <P>
  Internally, PCRE has a function called <b>match()</b>, which it calls repeatedly
- (possibly recursively) when matching a pattern. By controlling the maximum
+ (possibly recursively) when matching a pattern with the <b>pcre_exec()</b>
- number of times this function may be called during a single matching operation,
+ function. By controlling the maximum number of times this function may be
- a limit can be placed on the resources used by a single call to
+ called during a single matching operation, a limit can be placed on the
- <b>pcre_exec()</b>. The limit can be changed at run time, as described in the
+ resources used by a single call to <b>pcre_exec()</b>. The limit can be changed
+ at run time, as described in the
  <a href="pcreapi.html"><b>pcreapi</b></a>
  documentation. The default is 10 million, but this can be changed by adding a
  setting such as
  <pre>
    --with-match-limit=500000
  </pre>
- to the <b>configure</b> command.
+ to the <b>configure</b> command. This setting has no effect on the
+ <b>pcre_dfa_exec()</b> matching function.
  </P>
  <br><a name="SEC8" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br>
  <P>
-Line 148 
 of the compiled pattern, and this change
+Line 150 
 of the compiled pattern, and this change
  </P>
  <br><a name="SEC9" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br>
  <P>
- PCRE implements backtracking while matching by making recursive calls to an
+ When matching with the <b>pcre_exec()</b> function, PCRE implements backtracking
- internal function called <b>match()</b>. In environments where the size of the
+ by making recursive calls to an internal function called <b>match()</b>. In
- stack is limited, this can severely limit PCRE's operation. (The Unix
+ environments where the size of the stack is limited, this can severely limit
- environment does not usually suffer from this problem.) An alternative approach
+ PCRE's operation. (The Unix environment does not usually suffer from this
- that uses memory from the heap to remember data, instead of using recursive
+ problem.) An alternative approach that uses memory from the heap to remember
- function calls, has been implemented to work round this problem. If you want to
+ data, instead of using recursive function calls, has been implemented to work
- build a version of PCRE that works this way, add
+ round this problem. If you want to build a version of PCRE that works this way,
+ add
  <pre>
    --disable-stack-for-recursion
  </pre>
-Line 165 
 predictable: the block sizes requested a
+Line 168 
 predictable: the block sizes requested a
  always freed in reverse order. A calling program might be able to implement
  optimized functions that perform better than the standard <b>malloc()</b> and
  <b>free()</b> functions. PCRE runs noticeably more slowly when built in this
- way.
+ way. This option affects only the <b>pcre_exec()</b> function; it is not
+ relevant for the the <b>pcre_dfa_exec()</b> function.
  </P>
  <br><a name="SEC10" href="#TOC1">USING EBCDIC CODE</a><br>
  <P>
-Line 178 
 compiled to run in an EBCDIC environment
+Line 182 
 compiled to run in an EBCDIC environment
  to the <b>configure</b> command.
  </P>
  <P>
- Last updated: 09 September 2004
+ Last updated: 28 February 2005
  <br>
- Copyright &copy; 1997-2004 University of Cambridge.
+ Copyright &copy; 1997-2005 University of Cambridge.
  <p>
  Return to the <a href="index.html">PCRE index page</a>.
  </p>

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