     An empty, non constant-time size <code class="computeroutput"><a class="link" href="../boost/intrusive/avl_set.html" title="Class template avl_set">avl_set</a></code>,
      <code class="computeroutput"><a class="link" href="../boost/intrusive/avl_multiset.html" title="Class template avl_multiset">avl_multiset</a></code> or
      <code class="computeroutput"><a class="link" href="../boost/intrusive/avltree.html" title="Class template avltree">avltree</a></code> also has a size
      of 3 pointers and a