Releasing an ivar with the Copy property

Question

If I have a class

@interface Foo {
    NSString *temp;
}

@property(nonatomic, copy) NSString *temp;

@end

I understand that upon assignment, the old temp will get released and the new one will be assigned using temp = [newTemp copy] . And going by memory management rules, you are supposed to do [temp release] in the dealloc method of Foo, right?

What I don't understand is what happens if the setter was never used - you still have the [temp release] in the dealloc, so it's releasing something with a retain count of 0. Can someone clarify this for me?

Answer 1

There are two possibilities.

1. Since you never set it, it's nil . Sending release to nil is just fine. So no problem there.

2. Your init routine makes a default value for temp . Then it is a real object, and sending it release is also ok.

No problem all around! In neither case are you sending a message to an object with a retain count of 0.