e</span><span class="special">&amp;,</span> <span class="identifier">attribute_type</span><span class="special">&amp;)</span></code> or be both move-constructible
              and move-assignable.
            </p></td></tr>
</table></div>
<h6>
<a name="spirit.qi.reference.directive.hold.h6"></a>
            <span class="phrase"><a name="spirit.qi.reference.directive.hold.complexity"></a></span><a class="link" href="hold.html#spirit.qi.reference.directive.hold.complexity">Complexity</a>
          </h6>
<div