Who calls the dealloc method and when in Objective C?

Question

When a custom class is created in Objective C, when and how is the dealloc method called? Is it something that I have to implement somehow in my class?

Answer 1

Imagine that -release is implemented in NSObject like this:

- (void)release
{
    _retainCount--;
    if (_retainCount == 0) {
        [self dealloc]
    }
}

I'm sure it's a little more complicated than that, but the answer to your question is that the object itself will call -dealloc when its retain count drops to zero. However, your custom class will inherit this behavior from NSObject. You'll never need to call -dealloc yourself in code that you write; it'll always happen automatically when the object has been properly released.