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<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="asio.indexterm.asio_handler_allocate"></a>
</p>
<p>
(Deprecated: Use the <a class="link" href="associated_allocator.html" title="associated_allocator"><code class="computeroutput"><span class="identifier">associated_allocator</span></code></a> trait.) Default
allocation function for handlers.
</p>
<pre class="programlisting"><span class="identifier">asio_handler_allocate_is_deprecated</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>
The default implementation of these allocation hooks uses <code class="computeroutput"><span class="keyword">operator</span>
<span class="keyword">new</span></code> and <code class="computeroutput"><span class="keyword">operator</span>
<span class="keyword">delete</span></code>.
</p>
<h5>
<a name="asio.reference.asio_handler_allocate.h0"></a>
<span><a name="asio.reference.asio_handler_allocate.remarks"></a></span><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>
<h5>
<a name="asio.reference.asio_handler_allocate.h1"></a>
<span><a name="asio.reference.asio_handler_allocate.example"></a></span><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>
<h5>
<a name="asio.reference.asio_handler_allocate.h2"></a>
<span><a name="asio.reference.asio_handler_allocate.requirements"></a></span><a class="link" href="asio_handler_allocate.html#asio.reference.asio_handler_allocate.requirements">Requirements</a>
</h5>
<p>
<span class="emphasis"><em>Header: </em></span><code class="literal">asio/handler_alloc_hook.hpp</code>
</p>
<p>
<span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio.hpp</code>
</p>
</div>
<div class="copyright-footer">Copyright © 2003-2023 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>)
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