title: How does the following code work?
body: <pre><code>    #define TYPE_CHECK(T, S)                                     \
      while (false) {                                              \
        *(static_cast&lt;T* volatile*&gt;(0)) = static_cast&lt;S*&gt;(0);      \
      }
  </code></pre>
  
  <p>I am reading Google <a href="http://code.google.com/p/v8/source/browse/trunk/include/v8.h" rel="noreferrer">v8</a>'s code and found the above macro for type check.</p>
  
  <p>However, I do not understand why it works. while(false) never get executed, right?
  Can someone explain those lines?
  Thanks </p>