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<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">a</code> denotes a synchronous random-access write
        device 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">ec</code> denotes an object
        of type <code class="computeroutput">error_code</code>.
      </p>
<div class="table">
<a name="asio.reference.SyncRandomAccessWriteDevice.t0"></a><p class="title"><b>Table 29. 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">a.write_some_at(o, cb);</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">size_t</code>
                </p>
              </td>
<td>
                <p>
                  Equivalent to:
</p>
<pre class="programlisting">error_code ec;
size_t s = a.write_some(o, cb, ec);
if (ec) throw system_error(ec);
return s;
</pre>
<p>
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">a.write_some_at(o, cb, ec);</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">size_t</code>
                </p>
              </td>
<td>
                <p>
                  Writes one or more bytes of data to the device <code class="computeroutput">a</code> at
                  offset <code class="computeroutput">o</code>.<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">write_some_at</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">ec</code> such that <code class="computeroutput">!ec</code> is
                  true. If an error occurred, returns <code class="computeroutput">0</code> and sets <code class="computeroutput">ec</code>
                  such that <code class="computeroutput">!!ec</code> is true.<br> <br> If the total
                  size of all buffers in the sequence <code class="computeroutput">cb</code> is <code class="computeroutput">0</code>,
                  the function shall return <code class="computeroutput">0</code> immediately.
                </p>
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</tbody>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 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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