Question

am working my way through the “Beginning iPad Development” Apress book and have noticed that sometimes when the author is assigning values to a property they will use:

self.variable = value;

and other times, they will use:

variable = [value retain];

In both cases variable is a property defined as:

@property (nonatomic, retain) TYPE variable;

I wondered if anyone knew why this is done to help me better understand

Thanks,
William

Answer 1

They are often equivalent memory-wise. The compiler turns self.variable = value into [self setVariable:value] which then calls the generated setter (if you’re using @synthesize) and retains it for you.