How to understand `const LayerVector& currentLayers(anotherLayer);`
<pre><code> LayerVector anotherLayer;
 const LayerVector&amp; currentLayers(anotherLayer);
</code></pre>

<p>I can not understand the why the reference <code>&amp;</code> are used here.</p>

<p>EDIT:
My shame. I only know the reference could be defined in following way. The way above make me confused... Thank you guys!</p>

<pre><code> const LayerVector &amp;currentLayers = anotherLayer
</code></pre>
