d type of the <code class="computeroutput">variant</code> must
          fulfill the requirements of the
          <a class="link" href="../variant/reference.html#variant.concepts.output-streamable" title="OutputStreamable"><span class="emphasis"><em>OutputStreamable</em></span></a>
          concept.</td>
</tr>
<tr>
<td><p><span class="term">Effects:</span></p></td>
<td>Calls <code class="computeroutput">out &lt;&lt; x</code>, where <code class="computeroutput">x</code> is
          the content of <code cl