title: Objective-C declared @property attributes (nonatomic, copy, strong, weak)
body: <p>Can someone explain to me in detail when I must use each attribute: <code>nonatomic</code>, <code>copy</code>, <code>strong</code>, <code>weak</code>, and so on, for a declared property, and explain what each does? Some sort of example would be great also. I am using ARC.</p>