/span><span class="mlabel">nodiscard</span><span class="mlabel">noexcept</span></span>  </td>
  </tr>
</table>
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<p>Returns an iterable object to use to <em>visit</em> a group. </p>
<p>The iterable object returns tuples that contain the current entity and a set of references to its non-empty components. The <em>constness</em> of the components is as requested.</p>
<dl class="section note"><dt>Note</dt><dd>Empty types aren't explicitly instantiated and therefore they are never retur