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<title>Buffer-oriented synchronous random-access write device requirements</title>
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<div class="titlepage"><div><div><h3 class="title">
<a name="asio.reference.SyncRandomAccessWriteDevice"></a><a class="link" href="SyncRandomAccessWriteDevice.html" title="Buffer-oriented synchronous random-access write device requirements">Buffer-oriented
      synchronous random-access write device requirements</a>
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<p>
        In the table below, <code class="computeroutput"><span class="identifier">a</span></code> denotes
        a synchronous random-access write device object, <code class="computeroutput"><span class="identifier">o</span></code>
        denotes an offset of type <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">uint64_t</span></code>,
        <code class="computeroutput"><span class="identifier">cb</span></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"><span class="identifier">ec</span></code> denotes
        an object of type <code class="computeroutput"><span class="identifier">error_code</span></code>.
      </p>
<div class="table">
<a name="asio.reference.SyncRandomAccessWriteDevice.t0"></a><p class="title"><b>Table&#160;35.&#160;Buffer-oriented synchronous random-access write device requirements</b></p>
<div class="table-contents"><table class="table" summary="Buffer-oriented synchronous 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"><span class="identifier">a</span><span class="special">.</span><span class="identifier">write_some_at</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span>
                  <span class="identifier">cb</span><span class="special">);</span></code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">size_t</span></code>
                </p>
              </td>
<td>
                <p>
                  Equivalent to:
</p>
<pre class="programlisting"><span class="identifier">error_code</span> <span class="identifier">ec</span><span class="special">;</span>
<span class="identifier">size_t</span> <span class="identifier">s</span> <span class="special">=</span> <span class="identifier">a</span><span class="special">.</span><span class="identifier">write_some</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span> <span class="identifier">cb</span><span class="special">,</span> <span class="identifier">ec</span><span class="special">);</span>
<span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</span><span class="special">)</span> <span class="keyword">throw</span> <span class="identifier">system_error</span><span class="special">(</span><span class="identifier">ec</span><span class="special">);</span>
<span class="keyword">return</span> <span class="identifier">s</span><span class="special">;</span>
</pre>
<p>
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">write_some_at</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span>
                  <span class="identifier">cb</span><span class="special">,</span>
                  <span class="identifier">ec</span><span class="special">);</span></code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">size_t</span></code>
                </p>
              </td>
<td>
                <p>
                  Writes one or more bytes of data to the device <code class="computeroutput"><span class="identifier">a</span></code>
                  at offset <code class="computeroutput"><span class="identifier">o</span></code>.<br>
                  <br> The constant buffer sequence <code class="computeroutput"><span class="identifier">cb</span></code>
                  specifies memory where the data to be written is located. The
                  <code class="computeroutput"><span class="identifier">write_some_at</span></code> operation
                  shall always write a buffer in the sequence completely before proceeding
                  to the next.<br> <br> If successful, returns the number of
                  bytes written and sets <code class="computeroutput"><span class="identifier">ec</span></code>
                  such that <code class="computeroutput"><span class="special">!</span><span class="identifier">ec</span></code>
                  is true. If an error occurred, returns <code class="computeroutput"><span class="number">0</span></code>
                  and sets <code class="computeroutput"><span class="identifier">ec</span></code> such
                  that <code class="computeroutput"><span class="special">!!</span><span class="identifier">ec</span></code>
                  is true.<br> <br> If the total size of all buffers in the sequence
                  <code class="computeroutput"><span class="identifier">cb</span></code> is <code class="computeroutput"><span class="number">0</span></code>, the function shall return <code class="computeroutput"><span class="number">0</span></code> immediately.
                </p>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 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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