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| <div class="section"> |
| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="coroutine.stack"></a><a class="link" href="stack.html" title="Stack allocation">Stack allocation</a> |
| </h2></div></div></div> |
| <div class="toc"><dl class="toc"> |
| <dt><span class="section"><a href="stack/protected_stack_allocator.html">Class <span class="emphasis"><em>protected_stack_allocator</em></span></a></span></dt> |
| <dt><span class="section"><a href="stack/standard_stack_allocator.html">Class <span class="emphasis"><em>standard_stack_allocator</em></span></a></span></dt> |
| <dt><span class="section"><a href="stack/segmented_stack_allocator.html">Class <span class="emphasis"><em>segmented_stack_allocator</em></span></a></span></dt> |
| <dt><span class="section"><a href="stack/stack_traits.html">Class <span class="emphasis"><em>stack_traits</em></span></a></span></dt> |
| <dt><span class="section"><a href="stack/stack_context.html">Class <span class="emphasis"><em>stack_context</em></span></a></span></dt> |
| <dt><span class="section"><a href="stack/valgrind.html">Support for valgrind</a></span></dt> |
| </dl></div> |
| <p> |
| A <span class="emphasis"><em>coroutine</em></span> uses internally a <span class="emphasis"><em>context</em></span> |
| which manages a set of registers and a stack. The memory used by the stack |
| is allocated/deallocated via a <span class="emphasis"><em>stack-allocator</em></span> which is |
| required to model a <span class="emphasis"><em>stack-allocator concept</em></span>. |
| </p> |
| <h4> |
| <a name="coroutine.stack.h0"></a> |
| <span class="phrase"><a name="coroutine.stack._emphasis_stack_allocator_concept__emphasis_"></a></span><a class="link" href="stack.html#coroutine.stack._emphasis_stack_allocator_concept__emphasis_"><span class="emphasis"><em>stack-allocator |
| concept</em></span></a> |
| </h4> |
| <p> |
| A <span class="emphasis"><em>stack-allocator</em></span> must satisfy the <span class="emphasis"><em>stack-allocator |
| 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>stack-allocator</em></span> |
| 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> |
| is a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| expression |
| </p> |
| </th> |
| <th> |
| <p> |
| return type |
| </p> |
| </th> |
| <th> |
| <p> |
| notes |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">allocate</span><span class="special">(</span> |
| <span class="identifier">sctx</span><span class="special">,</span> |
| <span class="identifier">size</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">void</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| creates a stack of at least <code class="computeroutput"><span class="identifier">size</span></code> |
| bytes and stores its pointer and length in <code class="computeroutput"><span class="identifier">sctx</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">deallocate</span><span class="special">(</span> |
| <span class="identifier">sctx</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">void</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| 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> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="important"><table border="0" summary="Important"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> |
| <th align="left">Important</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The implementation of <code class="computeroutput"><span class="identifier">allocate</span><span class="special">()</span></code> might include logic to protect against |
| exceeding the context's available stack size rather than leaving it as undefined |
| behaviour. |
| </p></td></tr> |
| </table></div> |
| <div class="important"><table border="0" summary="Important"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> |
| <th align="left">Important</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| Calling <code class="computeroutput"><span class="identifier">deallocate</span><span class="special">()</span></code> |
| with a <code class="computeroutput"><span class="identifier">stack_context</span></code> not |
| set by <code class="computeroutput"><span class="identifier">allocate</span><span class="special">()</span></code> |
| results in undefined behaviour. |
| </p></td></tr> |
| </table></div> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The stack is not required to be aligned; alignment takes place inside <span class="emphasis"><em>coroutine</em></span>. |
| </p></td></tr> |
| </table></div> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| 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 |
| (growing downwards) or the bottom of the stack (growing upwards). |
| </p></td></tr> |
| </table></div> |
| <p> |
| class <span class="emphasis"><em>stack_allocator</em></span> is a typedef of <span class="emphasis"><em>standard_stack_allocator</em></span>. |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2009 Oliver Kowalke<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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>) |
| </p> |
| </div></td> |
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