title: default keyword virtual destructor
body: <p>I have been using more and more C++11 and I have come across something that I couldn't find anywhere. When we delete derived class from base pointer, we need to have virtual destructors;  but sometimes the parent destructor needs to be "pure", which is not really possible with C++. So, my question is can <strong>default</strong> be used for virtual destructors? I have already tried it and it works but I don't know if its safe as there is no information about it anywhere in the internet.</p>
  
  <p>EDIT: To clarify the problem, I am talking about using <code>virtual ~Class() = default;</code></p>