>lock</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
<p>Returns: expired()? shared_ptr&lt;T&gt;(): shared_ptr&lt;T&gt;(*this).</p>
<p>Throws: nothing. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">long</span> <a name="idp50619568-bb"></a><span class="identifier">use_count</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class