<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>asio_handler_allocate</title> <link rel="stylesheet" href="../../boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2"> <link rel="start" href="../../index.html" title="Asio"> <link rel="up" href="../reference.html" title="Reference"> <link rel="prev" href="add_service.html" title="add_service"> <link rel="next" href="asio_handler_deallocate.html" title="asio_handler_deallocate"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../asio.png"></td></tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="add_service.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="asio_handler_deallocate.html"><img src="../../next.png" alt="Next"></a> </div> <div class="section" lang="en"> <div class="titlepage"><div><div><h3 class="title"> <a name="asio.reference.asio_handler_allocate"></a><a class="link" href="asio_handler_allocate.html" title="asio_handler_allocate"> asio_handler_allocate</a> </h3></div></div></div> <p> <a class="indexterm" name="id577542"></a> Default allocation function for handlers. </p> <pre class="programlisting"><span class="keyword">void</span> <span class="special">*</span> <span class="identifier">asio_handler_allocate</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="special">...</span> <span class="special">);</span> </pre> <p> Asynchronous operations may need to allocate temporary objects. Since asynchronous operations have a handler function object, these temporary objects can be said to be associated with the handler. </p> <p> Implement asio_handler_allocate and asio_handler_deallocate for your own handlers to provide custom allocation for these temporary objects. </p> <p> This default implementation is simply: </p> <pre class="programlisting"><span class="keyword">return</span> <span class="special">::</span><span class="keyword">operator</span> <span class="keyword">new</span><span class="special">(</span><span class="identifier">size</span><span class="special">);</span> </pre> <a name="asio.reference.asio_handler_allocate.remarks"></a><h5> <a name="id577673"></a> <a class="link" href="asio_handler_allocate.html#asio.reference.asio_handler_allocate.remarks">Remarks</a> </h5> <p> All temporary objects associated with a handler will be deallocated before the upcall to the handler is performed. This allows the same memory to be reused for a subsequent asynchronous operation initiated by the handler. </p> <a name="asio.reference.asio_handler_allocate.example"></a><h5> <a name="id577698"></a> <a class="link" href="asio_handler_allocate.html#asio.reference.asio_handler_allocate.example">Example</a> </h5> <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">my_handler</span><span class="special">;</span> <span class="keyword">void</span><span class="special">*</span> <span class="identifier">asio_handler_allocate</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="identifier">my_handler</span><span class="special">*</span> <span class="identifier">context</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="special">::</span><span class="keyword">operator</span> <span class="keyword">new</span><span class="special">(</span><span class="identifier">size</span><span class="special">);</span> <span class="special">}</span> <span class="keyword">void</span> <span class="identifier">asio_handler_deallocate</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">pointer</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="identifier">my_handler</span><span class="special">*</span> <span class="identifier">context</span><span class="special">)</span> <span class="special">{</span> <span class="special">::</span><span class="keyword">operator</span> <span class="keyword">delete</span><span class="special">(</span><span class="identifier">pointer</span><span class="special">);</span> <span class="special">}</span> </pre> <a name="asio.reference.asio_handler_allocate.requirements"></a><h5> <a name="id577970"></a> <a class="link" href="asio_handler_allocate.html#asio.reference.asio_handler_allocate.requirements">Requirements</a> </h5> <p> <span class="bold"><strong>Header: </strong></span><code class="literal">asio/handler_alloc_hook.hpp</code> </p> <p> <span class="bold"><strong>Convenience header: </strong></span><code class="literal">asio.hpp</code> </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 © 2003 - 2010 Christopher M. Kohlhoff<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> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="add_service.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="asio_handler_deallocate.html"><img src="../../next.png" alt="Next"></a> </div> </body> </html>