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<div class="titlepage"><div><div><h3 class="title">
<a name="boost_asio.reference.AsyncRandomAccessWriteDevice"></a><a class="link" href="AsyncRandomAccessWriteDevice.html" title="Buffer-oriented asynchronous random-access write device requirements">Buffer-oriented
asynchronous random-access write device requirements</a>
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<p>
In the table below, <code class="computeroutput">a</code> denotes an asynchronous write stream object,
<code class="computeroutput">o</code> denotes an offset of type <code class="computeroutput">boost::uint64_t</code>, <code class="computeroutput">cb</code>
denotes an object satisfying <a class="link" href="ConstBufferSequence.html" title="Constant buffer sequence requirements">constant
buffer sequence</a> requirements, and <code class="computeroutput">h</code> denotes an object
satisfying <a class="link" href="WriteHandler.html" title="Write handler requirements">write handler</a>
requirements.
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<div class="table">
<a name="boost_asio.reference.AsyncRandomAccessWriteDevice.t0"></a><p class="title"><b>Table 3. Buffer-oriented asynchronous random-access write device requirements</b></p>
<div class="table-contents"><table class="table" summary="Buffer-oriented asynchronous random-access write device requirements">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
operation
</p>
</th>
<th>
<p>
type
</p>
</th>
<th>
<p>
semantics, pre/post-conditions
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput">a.get_executor()</code>
</p>
</td>
<td>
<p>
A type satisfying the <a class="link" href="Executor1.html" title="Executor requirements">Executor
requirements</a>.
</p>
</td>
<td>
<p>
Returns the associated I/O executor.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput">a.async_write_some_at(o, cb, h);</code>
</p>
</td>
<td>
<p>
<code class="computeroutput">void</code>
</p>
</td>
<td>
<p>
Initiates an asynchronous operation to write one or more bytes
of data to the device <code class="computeroutput">a</code> at offset <code class="computeroutput">o</code>.
The operation is performed via the <code class="computeroutput">io_service</code> object
<code class="computeroutput">a.get_io_service()</code> and behaves according to <a class="link" href="asynchronous_operations.html" title="Requirements on asynchronous operations">asynchronous
operation</a> requirements.<br> <br> The constant buffer
sequence <code class="computeroutput">cb</code> specifies memory where the data to be
written is located. The <code class="computeroutput">async_write_some_at</code> operation
shall always write a buffer in the sequence completely before proceeding
to the next.<br> <br> The implementation shall maintain one
or more copies of <code class="computeroutput">cb</code> until such time as the write
operation no longer requires access to the memory specified by
the buffers in the sequence. The program must ensure the memory
is valid until:<br> <br> — the last copy of <code class="computeroutput">cb</code> is
destroyed, or<br> <br> — the handler for the asynchronous write
operation is invoked,<br> <br> whichever comes first.<br>
<br> If the total size of all buffers in the sequence <code class="computeroutput">cb</code>
is <code class="computeroutput">0</code>, the asynchronous write operation shall complete
immediately and pass <code class="computeroutput">0</code> as the argument to the handler
that specifies the number of bytes written.
</p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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