title: Lazy initialization of C structs
body: <p>I'm not sure how to initialize a class property that's a C struct, or pre-iOS5 base type. This is what I'd do if I was dealing with a class, but I don't know what I can check to see if this is the first time the struct has been accessed, since they're undefined at creation:</p>
  
  <pre><code>@interface GraphView : UIView
  @property (nonatomic) CGPoint origin;
  @end
  
  
  @implementation GraphView
  @synthesize origin = _origin;
  
  - (CGPoint)origin
  {
      if (WHAT?) {
           _origin = CGPointMake(self.bounds.origin.x + self.bounds.size.width/2, 
                                 self.bounds.origin.y + self.bounds.size.height/2);
      }
      return _origin;
  }
  
  @end
  </code></pre>
  
  <p>I realize the primary benefit of lazy initialization is for memory allocation, but if I'm doing this for all the properties that are classes, it seems clearest to use the same style for setting starting values on all my properties.</p>
  
  <p>I can use some other instance variable or property to track whether the self.origin has been accessed, but that seems... not smooth. I could take care to never access self.origin before I've set it, which seems mildly entailed by the fact that structs are undefined at creation. </p>
  
  <p>Is there a "right" way?</p>