  return value optimization <a href="http://en.wikipedia.org/wiki/Return_value_optimization" target="_top">(RVO)</a>
        creating no temporary object and performing one copy of the first argument
        <code class="computeroutput"><span class="identifier">object</span></code>.
      </p>
<div class="caution"><table border="0" summary="Caution">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../../doc/src/images/caution.png"></td>
<th align="left">Caut