Question

I have a instance variable declared as a retain property & then I released it 2 times. After releasing it I am not using it. This is not resulting into any crash. Is there any other impact of releasing a variable more than required (given that the variable is not going to be used after the release):

@property (nonatomic, retain) NSString *myVariable;
self.myVariable = nil;
self.myVariable = nil;

Answer 1

You might be confused about the difference between a variable and an object. A single variable can be used with a release an infinite number of times (say, if is nil, or it holds a completely different retained object before each release, etc. This is because a variable can hold no object, or different objects at different times.). In your example, the variable holds no object (nil) during your second release.

But releasing any one non-nil object just one time too many can be the cause of a crash.