an></em></span> aN, error_code&amp; ec);
</pre>
<p>
        For an object <code class="computeroutput">s</code>, the conditions under which its synchronous
        socket operations may block the calling thread (C++Std [defns.block]) are
        determined as follows.
      </p>
<p>
        If:
      </p>
<p>
        &#8212; <code class="computeroutput">s.non_blocking() == true</code>,
      </p>
<p>
        &#8212; the synchronous socket operation is specified in terms of a <span class="emphasis"><em>POSIX