title: What happens when alloc or allocWithZone is called?
body: <p>I wanted to know , How exactly does an Objective C object gets created. I have been reading different blog posts and apple docs but I could only find incomplete information here and there about ivar and objc_class structures ad various other runtime methods and structures.</p>
  
  <p>But I still did not get, What happens when we call alloc on a Class and how are superclass data members added to the structure ?</p>
  
  <p>If possible, can any one Explain this to me or point me to the source code of these methods that actually allocate memory ?</p>