 is a valid
(constant or non-constant) iterator of some index of <code>*this</code>
(i.e. does not refer to some other <code>multi_index_container</code>.)<br>
<b>Effects:</b> Returns an <code>index&lt;Tag>::type::const_iterator</code>
iterator equivalent to <code>it</code>.<br>
<b>Complexity:</b> Constant.<br>
<b>Exception safety:</b> <code>nothrow</code>.
</blockquote>

<h4><a name="serialization">Serialization</a></h4>

<p>
<code>multi_index_container</code>s can be archived/retrieved by means of
<a href