empty base class optimization
<p>Two quotes from the C++ standard, §1.8:</p>

<blockquote>
  <p>An object is a region of storage.</p>
  
  <p>Base class subobjects may have zero size.</p>
</blockquote>

<p>I don't think a region of storage can be of size zero. That would mean that some base class subobjects aren't actually objects. How do these statements co-exist?</p>
