lass="term"><code class="computeroutput">meta</code></span></p></td>
<td><p>description of the axis. </p></td>
</tr>
</tbody>
</table></div></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> C<span class="special">&gt;</span> 
  <a name="idm14243-bb"></a><span class="identifier">category</span><span class="special">(</span><span class="keyword">const</span> <span