return type of the copy-assignment operator does not need
  to be specified. If left unspecified, it will default to an
  unqualified reference to the enclosing class type.</p>
<p>General documentation on functions in BoostBook is provided in
  the <a class="link" href="function.html" title="BoostBook element function"><code class="sgmltag-element">function</code></a>
  element documentation.</p>
</div>
<div class="refsection">
<a name="id-1.4.3.7.46.5"></a><h2>Attributes</h2>
<div class="informaltable"><ta