th</span><span class="special">&lt;</span><span class="identifier">position_cache_tag</span><span class="special">&gt;(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">positions</span><span class="special">))</span>
    <span class="special">[</span>
        <span class="identifier">employees</span>
    <span class="special">];</span>
</pre>
<p>
        Typically this is done just before calling