title: Is emplace only advantageous over push when the object being emplaced is a non-POD and an r-value?
body: <p>From what I've read regarding <code>emplace</code> vs <code>push</code> for STL containers, the benefit of <code>emplace</code> over <code>push</code> is only evident when the object you're emplacing is an r-value and a non-POD type. Is this the only situation in which <code>emplace</code> is faster?</p>