title: What does the property "Nonatomic" mean?
body: <p>What does "nonatomic" mean in this code?</p>
  
  <pre><code>@property(nonatomic, retain) UITextField *theUsersName;
  </code></pre>
  
  <p>What is the difference between atomic and nonatomic?</p>
  
  <p>Thanks</p>