
<p>The hook admits the following options: <code class="computeroutput">tag&lt;&gt;</code>, <code class="computeroutput">void_pointer&lt;&gt;</code>, <code class="computeroutput">link_mode&lt;&gt;</code>, <code class="computeroutput">store_hash&lt;&gt;</code> and <code class="computeroutput">optimize_multikey&lt;&gt;</code>.</p>
<p><code class="computeroutput">tag&lt;&gt;</code> defines a tag to identify the node. The same tag value can be used in different classes, but if a class is derived from more than 