title: What does "CALLBACK" in a Windows API function declaration mean?
body: <blockquote>
  <p><strong>Possible Duplicate:</strong><br />
  <a href="https://stackoverflow.com/questions/530504/what-does-a-callback-declaration-in-c-do">What does a “CALLBACK” declaration in C do?</a></p>
  </blockquote>
  
  <p>The prototype of a WindowProc() function is this</p>
  <pre><code>LRESULT CALLBACK WindowProc(HWND hWnd,UINT message , WPARAM wParan, LPARAM lParam);
  </code></pre>
  <p>But I've never come across the CALLBACK keyword, I only know that a callback function is one you pass a pointer to another function to, so what exactly is this CALLBACK over here? and what does it do?</p>