title: Is it possible to compare #ifdef values for conditional use
body: <p>I'm trying to come up with a generic, easy to use way to only run certain code, depending upon the api I am using at the time.</p>
  
  <p>In a header:</p>
  
  <pre><code>#define __API_USED cocos2d-x
  
  #define COCOS2DX  cocos2d-x
  #define OPENGL opengl
  
  #ifdef __API_USED == COCOS2DX
      #define USING_COCOS2DX
      #undef USING_OPENGL
  #endif
  </code></pre>
  
  <p>in source:</p>
  
  <pre><code>#ifdef USING_COCOS2DX
      ......
  #endif
  </code></pre>
  
  <p>However I don't think this would work.</p>
  
  <p>Is there a way to accomplish what I am looking to do?</p>