104 lines
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104 lines
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<div class="titlepage"><div><div><h3 class="title">
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<a name="boost_asio.reference.asio_handler_allocate"></a><a class="link" href="asio_handler_allocate.html" title="asio_handler_allocate">asio_handler_allocate</a>
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</h3></div></div></div>
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<p>
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<a class="indexterm" name="boost_asio.indexterm.asio_handler_allocate"></a>
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(Deprecated:
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Use the <a class="link" href="associated_allocator.html" title="associated_allocator"><code class="computeroutput">associated_allocator</code></a>
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trait.) Default allocation function for handlers.
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</p>
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<pre class="programlisting">asio_handler_allocate_is_deprecated asio_handler_allocate(
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std::size_t size,
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... );
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</pre>
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<p>
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Asynchronous operations may need to allocate temporary objects. Since asynchronous
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operations have a handler function object, these temporary objects can be
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said to be associated with the handler.
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</p>
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<p>
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Implement asio_handler_allocate and asio_handler_deallocate for your own
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handlers to provide custom allocation for these temporary objects.
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</p>
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<p>
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The default implementation of these allocation hooks uses <code class="computeroutput">operator
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new</code> and <code class="computeroutput">operator delete</code>.
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</p>
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<h5>
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<a name="boost_asio.reference.asio_handler_allocate.h0"></a>
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<span class="phrase"><a name="boost_asio.reference.asio_handler_allocate.remarks"></a></span><a class="link" href="asio_handler_allocate.html#boost_asio.reference.asio_handler_allocate.remarks">Remarks</a>
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</h5>
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<p>
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All temporary objects associated with a handler will be deallocated before
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the upcall to the handler is performed. This allows the same memory to be
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reused for a subsequent asynchronous operation initiated by the handler.
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</p>
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<h5>
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<a name="boost_asio.reference.asio_handler_allocate.h1"></a>
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<span class="phrase"><a name="boost_asio.reference.asio_handler_allocate.example"></a></span><a class="link" href="asio_handler_allocate.html#boost_asio.reference.asio_handler_allocate.example">Example</a>
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</h5>
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<pre class="programlisting">class my_handler;
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void* asio_handler_allocate(std::size_t size, my_handler* context)
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{
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return ::operator new(size);
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}
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void asio_handler_deallocate(void* pointer, std::size_t size,
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my_handler* context)
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{
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::operator delete(pointer);
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}
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</pre>
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<h5>
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<a name="boost_asio.reference.asio_handler_allocate.h2"></a>
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<span class="phrase"><a name="boost_asio.reference.asio_handler_allocate.requirements"></a></span><a class="link" href="asio_handler_allocate.html#boost_asio.reference.asio_handler_allocate.requirements">Requirements</a>
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</h5>
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<p>
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<span class="emphasis"><em>Header: </em></span><code class="literal">boost/asio/handler_alloc_hook.hpp</code>
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</p>
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<p>
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<span class="emphasis"><em>Convenience header: </em></span><code class="literal">boost/asio.hpp</code>
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</p>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2021 Christopher
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M. Kohlhoff<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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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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