title: Invalid token at start of a preprocessor expression Xcode
body: <pre><code>#define A7VERSION() ({[[[[[UIDevice currentDevice] systemVersion] componentsSeparatedByString:@"."] objectAtIndex:0] intValue];})
  
  #define IS_OS_7 A7VERSION()&gt;=7
  </code></pre>
  
  <p>The above declaration seems to compile well.</p>
  
  <p>But as soon as I add it a .m file I get the following exception  "invalid token at start of a preprocessor expression". I am not able to understand where I could be wrong</p>
  
  <pre><code>@implementation AppViewController
  #if IS_OS_7
  ….
  #else
  ….  
  #endif
  @end
  </code></pre>