lement is not in a container. Iterators to e1 and e2 related to those nodes are invalidated.</p>
<p><span class="bold"><strong>Complexity</strong></span>: Constant</p>
<p><span class="bold"><strong>Throws</strong></span>: Nothing. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="idp65830368-bb"></a><span class="identifier">is_linked</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">