How to get a number from unsigned long long mask?
<p>I wonder how to reverse something like <a href="http://stackoverflow.com/questions/16037785/how-to-get-long-long-mask-by-number">this</a>. So having a <code>mask</code> where <code>auto mask = 1ULL &lt;&lt; 20;</code> how to get <code>20</code> out from mask?</p>
