ntifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span> <span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
</pre>
<p>
            This function is used to determine the number of bytes that may be read
            without blocking.
          </p>
<h6>
<a name="boost_asio.reference.basic_da