rk
          (1 of 2 overloads)</a>
</h5></div></div></div>
<p>
            <span class="emphasis"><em>Inherited from basic_socket.</em></span>
          </p>
<p>
            Determine whether the socket is at the out-of-band data mark.
          </p>
<pre class="programlisting">bool at_mark() const;
</pre>
<p>
            This function is used to check whether the socket input is currently
            positioned at the out-of-band data mark.
          </p>
<h6>
<a name="boost_asio.reference.basic_seq_packe