ceph/src/boost/libs/context/doc/html/context/stack.html

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  26 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  27 <a name="context.stack"></a><a name="stack"></a><a class="link" href="stack.html" title="Stack allocation">Stack allocation</a>
  28 </h2></div></div></div>
  29 <div class="toc"><dl>
  30 <dt><span class="section"><a href="stack/protected_fixedsize.html">Class <span class="emphasis"><em>protected_fixedsize</em></span></a></span></dt>
  31 <dt><span class="section"><a href="stack/pooled_fixedsize.html">Class <span class="emphasis"><em>pooled_fixedsize_stack</em></span></a></span></dt>
  32 <dt><span class="section"><a href="stack/fixedsize.html">Class <span class="emphasis"><em>fixedsize_stack</em></span></a></span></dt>
  33 <dt><span class="section"><a href="stack/segmented.html">Class <span class="emphasis"><em>segmented_stack</em></span></a></span></dt>
  34 <dt><span class="section"><a href="stack/stack_traits.html">Class <span class="emphasis"><em>stack_traits</em></span></a></span></dt>
  35 <dt><span class="section"><a href="stack/stack_context.html">Class <span class="emphasis"><em>stack_context</em></span></a></span></dt>
  36 <dt><span class="section"><a href="stack/valgrind.html">Support for valgrind</a></span></dt>
  37 </dl></div>
  38 <p>
  39       The memory used by the stack is allocated/deallocated via a <span class="emphasis"><em>StackAllocator</em></span>
  40       which is required to model a <span class="emphasis"><em>stack-allocator concept</em></span>.
  41     </p>
  42 <h4>
  43 <a name="context.stack.h0"></a>
  44       <span><a name="context.stack._emphasis_stack_allocator_concept__emphasis_"></a></span><a class="link" href="stack.html#context.stack._emphasis_stack_allocator_concept__emphasis_"><span class="emphasis"><em>stack-allocator
  45       concept</em></span></a>
  46     </h4>
  47 <p>
  48       A <span class="emphasis"><em>StackAllocator</em></span> must satisfy the <span class="emphasis"><em>stack-allocator
  49       concept</em></span> requirements shown in the following table, in which <code class="computeroutput"><span class="identifier">a</span></code> is an object of a <span class="emphasis"><em>StackAllocator</em></span>
  50       type, <code class="computeroutput"><span class="identifier">sctx</span></code> is a <code class="computeroutput"><span class="identifier">stack_context</span></code>, and <code class="computeroutput"><span class="identifier">size</span></code>
  51       is a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>:
  52     </p>
  53 <div class="informaltable"><table class="table">
  54 <colgroup>
  55 <col>
  56 <col>
  57 <col>
  58 </colgroup>
  59 <thead><tr>
  60 <th>
  61               <p>
  62                 expression
  63               </p>
  64             </th>
  65 <th>
  66               <p>
  67                 return type
  68               </p>
  69             </th>
  70 <th>
  71               <p>
  72                 notes
  73               </p>
  74             </th>
  75 </tr></thead>
  76 <tbody>
  77 <tr>
  78 <td>
  79               <p>
  80                 <code class="computeroutput"><span class="identifier">a</span><span class="special">(</span><span class="identifier">size</span><span class="special">)</span></code>
  81               </p>
  82             </td>
  83 <td>
  84             </td>
  85 <td>
  86               <p>
  87                 creates a stack allocator
  88               </p>
  89             </td>
  90 </tr>
  91 <tr>
  92 <td>
  93               <p>
  94                 <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">allocate</span><span class="special">()</span></code>
  95               </p>
  96             </td>
  97 <td>
  98               <p>
  99                 <code class="computeroutput"><span class="identifier">stack_context</span></code>
 100               </p>
 101             </td>
 102 <td>
 103               <p>
 104                 creates a stack
 105               </p>
 106             </td>
 107 </tr>
 108 <tr>
 109 <td>
 110               <p>
 111                 <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">deallocate</span><span class="special">(</span>
 112                 <span class="identifier">sctx</span><span class="special">)</span></code>
 113               </p>
 114             </td>
 115 <td>
 116               <p>
 117                 <code class="computeroutput"><span class="keyword">void</span></code>
 118               </p>
 119             </td>
 120 <td>
 121               <p>
 122                 deallocates the stack created by <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">allocate</span><span class="special">()</span></code>
 123               </p>
 124             </td>
 125 </tr>
 126 </tbody>
 127 </table></div>
 128 <div class="important"><table border="0" summary="Important">
 129 <tr>
 130 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td>
 131 <th align="left">Important</th>
 132 </tr>
 133 <tr><td align="left" valign="top"><p>
 134         The implementation of <code class="computeroutput"><span class="identifier">allocate</span><span class="special">()</span></code> might include logic to protect against
 135         exceeding the context's available stack size rather than leaving it as undefined
 136         behaviour.
 137       </p></td></tr>
 138 </table></div>
 139 <div class="important"><table border="0" summary="Important">
 140 <tr>
 141 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td>
 142 <th align="left">Important</th>
 143 </tr>
 144 <tr><td align="left" valign="top"><p>
 145         Calling <code class="computeroutput"><span class="identifier">deallocate</span><span class="special">()</span></code>
 146         with a <code class="computeroutput"><span class="identifier">stack_context</span></code> not
 147         set by <code class="computeroutput"><span class="identifier">allocate</span><span class="special">()</span></code>
 148         results in undefined behaviour.
 149       </p></td></tr>
 150 </table></div>
 151 <div class="note"><table border="0" summary="Note">
 152 <tr>
 153 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td>
 154 <th align="left">Note</th>
 155 </tr>
 156 <tr><td align="left" valign="top"><p>
 157         The stack is not required to be aligned; alignment takes place inside <span class="emphasis"><em>execution_context</em></span>.
 158       </p></td></tr>
 159 </table></div>
 160 <div class="note"><table border="0" summary="Note">
 161 <tr>
 162 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td>
 163 <th align="left">Note</th>
 164 </tr>
 165 <tr><td align="left" valign="top"><p>
 166         Depending on the architecture <code class="computeroutput"><span class="identifier">allocate</span><span class="special">()</span></code> stores an address from the top of the stack
 167         (growing downwards) or the bottom of the stack (growing upwards).
 168       </p></td></tr>
 169 </table></div>
 170 </div>
 171 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 172 <td align="left"></td>
 173 <td align="right"><div class="copyright-footer">Copyright &#169; 2014 Oliver Kowalke<p>
 174         Distributed under the Boost Software License, Version 1.0. (See accompanying
 175         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>)
 176       </p>
 177 </div></td>
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