title: <Cocoa/Cocoa.h> location
body: <p>I am new to Mac OS X development. In XCode/Cocoa developers environment each Objective-C projects starts with<br>
  <code>#import &lt;Cocoa/Cocoa.h&gt;</code><br>
  It works fine but I am puzzled with Cocoa.h file location. There is no Cocoa.h file in Cocoa folder on my file system. I tried to "find / Cocoa/Cocoa.h" and "locate Cocoa/Cocoa.h" nothing was found.<br>
  Can anybody give me a hint on how and where compiler finds Cocoa.h header in above #import statement.</p>
  
  <p>Thanks,
  Recovering Microsoft Addict</p>