1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Algorithm Tuning</title> 5<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Boost.Regex 5.1.4"> 8<link rel="up" href="../configuration.html" title="Configuration"> 9<link rel="prev" href="algorithm.html" title="Algorithm Selection"> 10<link rel="next" href="../install.html" title="Building and Installing the Library"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="algorithm.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../configuration.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../install.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_regex.configuration.tuning"></a><a class="link" href="tuning.html" title="Algorithm Tuning">Algorithm Tuning</a> 28</h3></div></div></div> 29<p> 30 The following option applies only if BOOST_REGEX_RECURSIVE is set. 31 </p> 32<div class="informaltable"><table class="table"> 33<colgroup> 34<col> 35<col> 36</colgroup> 37<thead><tr> 38<th> 39 <p> 40 macro 41 </p> 42 </th> 43<th> 44 <p> 45 description 46 </p> 47 </th> 48</tr></thead> 49<tbody><tr> 50<td> 51 <p> 52 BOOST_REGEX_HAS_MS_STACK_GUARD 53 </p> 54 </td> 55<td> 56 <p> 57 Tells Boost.Regex that Microsoft style __try - __except blocks 58 are supported, and can be used to safely trap stack overflow. 59 </p> 60 </td> 61</tr></tbody> 62</table></div> 63<p> 64 The following options apply only if BOOST_REGEX_NON_RECURSIVE is set. 65 </p> 66<div class="informaltable"><table class="table"> 67<colgroup> 68<col> 69<col> 70</colgroup> 71<thead><tr> 72<th> 73 <p> 74 macro 75 </p> 76 </th> 77<th> 78 <p> 79 description 80 </p> 81 </th> 82</tr></thead> 83<tbody> 84<tr> 85<td> 86 <p> 87 BOOST_REGEX_BLOCKSIZE 88 </p> 89 </td> 90<td> 91 <p> 92 In non-recursive mode, Boost.Regex uses largish blocks of memory 93 to act as a stack for the state machine, the larger the block size 94 then the fewer allocations that will take place. This defaults 95 to 4096 bytes, which is large enough to match the vast majority 96 of regular expressions without further allocations, however, you 97 can choose smaller or larger values depending upon your platforms 98 characteristics. 99 </p> 100 </td> 101</tr> 102<tr> 103<td> 104 <p> 105 BOOST_REGEX_MAX_BLOCKS 106 </p> 107 </td> 108<td> 109 <p> 110 Tells Boost.Regex how many blocks of size BOOST_REGEX_BLOCKSIZE 111 it is permitted to use. If this value is exceeded then Boost.Regex 112 will stop trying to find a match and throw a std::runtime_error. 113 Defaults to 1024, don't forget to tweak this value if you alter 114 BOOST_REGEX_BLOCKSIZE by much. 115 </p> 116 </td> 117</tr> 118<tr> 119<td> 120 <p> 121 BOOST_REGEX_MAX_CACHE_BLOCKS 122 </p> 123 </td> 124<td> 125 <p> 126 Tells Boost.Regex how many memory blocks to store in it's internal 127 cache - memory blocks are taken from this cache rather than by 128 calling ::operator new. Generally speaking this can be an order 129 of magnitude faster than calling ::opertator new each time a memory 130 block is required, but has the downside that Boost.Regex can end 131 up caching a large chunk of memory (by default up to 16 blocks 132 each of BOOST_REGEX_BLOCKSIZE size). If memory is tight then try 133 defining this to 0 (disables all caching), or if that is too slow, 134 then a value of 1 or 2, may be sufficient. On the other hand, on 135 large multi-processor, multi-threaded systems, you may find that 136 a higher value is in order. 137 </p> 138 </td> 139</tr> 140</tbody> 141</table></div> 142</div> 143<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 144<td align="left"></td> 145<td align="right"><div class="copyright-footer">Copyright © 1998-2013 John Maddock<p> 146 Distributed under the Boost Software License, Version 1.0. (See accompanying 147 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 148 </p> 149</div></td> 150</tr></table> 151<hr> 152<div class="spirit-nav"> 153<a accesskey="p" href="algorithm.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../configuration.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../install.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 154</div> 155</body> 156</html> 157
