   If Value copy constructor or copy assignment throws.
              </li>
<li class="listitem">
                If allocation throws or returns invalid value.
              </li>
</ul></div>
<div class="warning"><table border="0" summary="Warning">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../../../../doc/src/images/warning.png"></td>
<th align="left">Warning</th>
</tr>
<tr><td align="left" valign="top"><p>
              This operation only guarantee