title: Duplicate symbol error — global constant
body: <p>In the header of the class, outside of interface declaration, I've declared global constants:</p>
  
  <pre><code>NSString * const gotFilePathNotification = @"gotFilePath";
  NSString * const gotResultNotification = @"gotResultOfType";
  </code></pre>
  
  <p>gotResultNotification is used only in this class (yet), but I reference gotFilePathNotificaion in another class implementation. To do it, I import this header.</p>
  
  <p>When I try to compile, I get a duplicate symbol linker error about gotFilePathNotification in this header. Why does it happen?</p>