iOS Programming: The Big Nerd Ranch Guide

For the More Curious: Property Synthesis

When explaining properties in this chapter, we noted that a property automatically generates the implementation for the accessor methods and it declares and creates an instance variable. While this is true, we omitted the fact that this behavior is only the default and you have other options.

Declaring a property in a class interface only declares the accessor methods in a class interface. In order for a property to automatically generate an instance variable and the implementations for its methods, it must be synthesized, either implicitly or explicitly. Properties are implicitly synthesized by default. A property is explicitly synthesized by using the @synthesize directive in an implementation ...