identifier>street_locator</span><span class=special>;</span>
</pre></blockquote>

<p>
Also, equality of composite keys can be tuned with
<a href="../reference/key_extraction.html#composite_key_equal_to"><code>composite_key_equal_to</code></a>,
though in most cases the default equality predicate (relying on
the <code>std::equal_to</code> instantiations for the element types)
will be the right choice.
</p>

<p>
Unlike with ordered indices, we cannot perform partial searches specifying
only the first elements 