ier">implementation_type</span> <span class="identifier">u</span><span class="special">;</span></code>
                </p>
              </td>
<td>
              </td>
<td>
                <p>
                  note: <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">implementation_type</span></code> has a public
                  default constructor and destructor.
                </p>
              </td>
</tr>
<tr>
<td>
                <p