1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Class pooled_fixedsize_stack</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="Chapter 1. Context"> 8<link rel="up" href="../stack.html" title="Stack allocation"> 9<link rel="prev" href="protected_fixedsize.html" title="Class protected_fixedsize"> 10<link rel="next" href="fixedsize.html" title="Class fixedsize_stack"> 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="protected_fixedsize.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../stack.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="fixedsize.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="context.stack.pooled_fixedsize"></a><a class="link" href="pooled_fixedsize.html" title="Class pooled_fixedsize_stack">Class <span class="emphasis"><em>pooled_fixedsize_stack</em></span></a> 28</h3></div></div></div> 29<p> 30 <span class="bold"><strong>Boost.Context</strong></span> provides the class <span class="emphasis"><em>pooled_fixedsize_stack</em></span> 31 which models the <span class="emphasis"><em>stack-allocator concept</em></span>. In contrast 32 to <span class="emphasis"><em>protected_fixedsize_stack</em></span> it does not append a guard 33 page at the end of each stack. The memory is managed internally by <a href="http://www.boost.org/doc/libs/release/libs/pool/doc/html/boost/pool.html" target="_top"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">pool</span><span class="special"><></span></code></a>. 34 </p> 35<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">context</span><span class="special">/</span><span class="identifier">pooled_fixedsize_stack</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 36 37<span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">traitsT</span> <span class="special">></span> 38<span class="keyword">struct</span> <span class="identifier">basic_pooled_fixedsize_stack</span> <span class="special">{</span> 39 <span class="keyword">typedef</span> <span class="identifier">traitT</span> <span class="identifier">traits_type</span><span class="special">;</span> 40 41 <span class="identifier">basic_pooled_fixedsize_stack</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">stack_size</span> <span class="special">=</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">default_size</span><span class="special">(),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">next_size</span> <span class="special">=</span> <span class="number">32</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">max_size</span> <span class="special">=</span> <span class="number">0</span><span class="special">);</span> 42 43 <span class="identifier">stack_context</span> <span class="identifier">allocate</span><span class="special">();</span> 44 45 <span class="keyword">void</span> <span class="identifier">deallocate</span><span class="special">(</span> <span class="identifier">stack_context</span> <span class="special">&);</span> 46<span class="special">}</span> 47 48<span class="keyword">typedef</span> <span class="identifier">basic_pooled_fixedsize_stack</span><span class="special"><</span> <span class="identifier">stack_traits</span> <span class="special">></span> <span class="identifier">pooled_fixedsize_stack</span><span class="special">;</span> 49</pre> 50<h5> 51<a name="context.stack.pooled_fixedsize.h0"></a> 52 <span class="phrase"><a name="context.stack.pooled_fixedsize._code__phrase_role__identifier__basic_pooled_fixedsize_stack__phrase__phrase_role__special_____phrase__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stack_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__next_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__max_size__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__identifier__basic_pooled_fixedsize_stack__phrase__phrase_role__special_____phrase__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stack_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__next_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__max_size__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><span class="identifier">basic_pooled_fixedsize_stack</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> 53 <span class="identifier">stack_size</span><span class="special">,</span> 54 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">next_size</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">max_size</span><span class="special">)</span></code></a> 55 </h5> 56<div class="variablelist"> 57<p class="title"><b></b></p> 58<dl class="variablelist"> 59<dt><span class="term">Preconditions:</span></dt> 60<dd><p> 61 <code class="computeroutput"><span class="special">!</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span> <span class="special">&&</span> 62 <span class="special">(</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span> <span class="special">>=</span> <span class="identifier">stack_size</span><span class="special">)</span></code> 63 and <code class="computeroutput"><span class="number">0</span> <span class="special"><</span> 64 <span class="identifier">nest_size</span></code>. 65 </p></dd> 66<dt><span class="term">Effects:</span></dt> 67<dd><p> 68 Allocates memory of at least <code class="computeroutput"><span class="identifier">stack_size</span></code> 69 Bytes and stores a pointer to the stack and its actual size in <code class="computeroutput"><span class="identifier">sctx</span></code>. Depending on the architecture 70 (the stack grows downwards/upwards) the stored address is the highest/lowest 71 address of the stack. Argument <code class="computeroutput"><span class="identifier">next_size</span></code> 72 determines the number of stacks to request from the system the first 73 time that <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> 74 needs to allocate system memory. The third argument <code class="computeroutput"><span class="identifier">max_size</span></code> 75 controls how many memory might be allocated for stacks - a value of 76 zero means no uper limit. 77 </p></dd> 78</dl> 79</div> 80<h5> 81<a name="context.stack.pooled_fixedsize.h1"></a> 82 <span class="phrase"><a name="context.stack.pooled_fixedsize._code__phrase_role__identifier__stack_context__phrase___phrase_role__identifier__allocate__phrase__phrase_role__special______phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__identifier__stack_context__phrase___phrase_role__identifier__allocate__phrase__phrase_role__special______phrase___code_"><code class="computeroutput"><span class="identifier">stack_context</span> <span class="identifier">allocate</span><span class="special">()</span></code></a> 83 </h5> 84<div class="variablelist"> 85<p class="title"><b></b></p> 86<dl class="variablelist"> 87<dt><span class="term">Preconditions:</span></dt> 88<dd><p> 89 <code class="computeroutput"><span class="special">!</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span> <span class="special">&&</span> 90 <span class="special">(</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span> <span class="special">>=</span> <span class="identifier">stack_size</span><span class="special">)</span></code>. 91 </p></dd> 92<dt><span class="term">Effects:</span></dt> 93<dd><p> 94 Allocates memory of at least <code class="computeroutput"><span class="identifier">stack_size</span></code> 95 Bytes and stores a pointer to the stack and its actual size in <code class="computeroutput"><span class="identifier">sctx</span></code>. Depending on the architecture 96 (the stack grows downwards/upwards) the stored address is the highest/lowest 97 address of the stack. 98 </p></dd> 99</dl> 100</div> 101<h5> 102<a name="context.stack.pooled_fixedsize.h2"></a> 103 <span class="phrase"><a name="context.stack.pooled_fixedsize._code__phrase_role__keyword__void__phrase___phrase_role__identifier__deallocate__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__keyword__void__phrase___phrase_role__identifier__deallocate__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">deallocate</span><span class="special">(</span> <span class="identifier">stack_context</span> 104 <span class="special">&</span> <span class="identifier">sctx</span><span class="special">)</span></code></a> 105 </h5> 106<div class="variablelist"> 107<p class="title"><b></b></p> 108<dl class="variablelist"> 109<dt><span class="term">Preconditions:</span></dt> 110<dd><p> 111 <code class="computeroutput"><span class="identifier">sctx</span><span class="special">.</span><span class="identifier">sp</span></code> is valid, <code class="computeroutput"><span class="special">!</span> 112 <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span> 113 <span class="special">&&</span> <span class="special">(</span> 114 <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span> 115 <span class="special">>=</span> <span class="identifier">sctx</span><span class="special">.</span><span class="identifier">size</span><span class="special">)</span></code>. 116 </p></dd> 117<dt><span class="term">Effects:</span></dt> 118<dd><p> 119 Deallocates the stack space. 120 </p></dd> 121</dl> 122</div> 123</div> 124<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 125<td align="left"></td> 126<td align="right"><div class="copyright-footer">Copyright © 2014 Oliver Kowalke<p> 127 Distributed under the Boost Software License, Version 1.0. (See accompanying 128 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>) 129 </p> 130</div></td> 131</tr></table> 132<hr> 133<div class="spirit-nav"> 134<a accesskey="p" href="protected_fixedsize.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../stack.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="fixedsize.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 135</div> 136</body> 137</html> 138
