title: Why is my 'kMyConstant' macro redefined?
body: <p>In my app delegate class I define a constant like so:</p>
  
  <pre><code>#define kSomeConstant    @"My_Constant_Value"
  </code></pre>
  
  <p>I then want to make use of this constant in another viewController so I defined it again exactly as above. I now get the message:</p>
  
  <pre><code>'kSomeConstant' macro redefined
  </code></pre>
  
  <p>Why is this the case? Is there some other way I can access the constant?</p>