title: C enum definition in iOS framework class
body: <p>I am browsing the UIKit framework header files and I see a lot of instances where an anonymous enum is defined followed by a seemingly related typedef.  Can someone explain what is going on here?  </p>
  
  <p>Does the <code>UIViewAutoresizing</code> type somehow (implicitly) refer to the enum declared in the previous statement?  How would you refer to that enum type?</p>
  
  <pre><code>enum {
      UIViewAutoresizingNone                 = 0,
      UIViewAutoresizingFlexibleLeftMargin   = 1 &lt;&lt; 0,
      UIViewAutoresizingFlexibleWidth        = 1 &lt;&lt; 1,
      UIViewAutoresizingFlexibleRightMargin  = 1 &lt;&lt; 2,
      UIViewAutoresizingFlexibleTopMargin    = 1 &lt;&lt; 3,
      UIViewAutoresizingFlexibleHeight       = 1 &lt;&lt; 4,
      UIViewAutoresizingFlexibleBottomMargin = 1 &lt;&lt; 5
  };
  typedef NSUInteger UIViewAutoresizing;
  </code></pre>