title: Hashing pointers as Keys for unordered_map in C++ STL
body: <p>I posted a similar <a href="https://stackoverflow.com/questions/25122932/pointers-as-keys-in-map-c-stl">quetion</a> regarding using pointers as Keys on maps in C++ STL. How are pointers hashed in unordered_maps when used as Keys. More specifically if I define:</p>
  
  <pre><code>std::unordered_map&lt; CustomClass*, int &gt; foo;
  </code></pre>
  
  <p>Would the default C++ std::hash implementation work to handle these pointers? Is it safe to use? Is this good practice?</p>