title: Defining Global Constants in Objective-C
body: <p>I have a constants.h file that looks something like</p>
  
  <pre><code>#ifndef constants_h
  #define constants_h
  
  #define MyAdUnitID @"XXXXXXX"
  #define GoogleAnalyticsID = @"XXXXX"
  
  #endif
  </code></pre>
  
  <p>and want to reference it throughout my other implementation files. These are just simple string values that I want as NSString instances throughout my program, but can't seem to get it to work.</p>
  
  <p>If there is a better practice to this, please let me know!</p>