Question

If a retain (reference) count of an object is greater than 1 in a dealloc method right before releasing does this mean there will be a memory leak?

I was debugging my code to find another issue but then ran into this subtle one. One of my object’s retain counts was 3 in the dealloc method. This object is a property with retain and is only called within the class. Now I imagine that the retain count should be 1 for all objects in the dealloc method before releasing right?

Here’s a sample dealloc method in a custom class:

- (void)dealloc {
    // Prints: "myObject retaincount: 3"
    NSLog(@"myObject retaincount: %d", [myObject retainCount]);

    // myObject retain count will be 2 after this call
    [myObject release];

    [super dealloc];
}

Is this normal?

Answer 1

If myObject is passed to some other object (say ‘anObj’) via a method (say ‘method:’) as in

 [anObj method:myObject];

anObj can retain myObject if needed. Then it is perfectly reasonable that when dealloc of the object containing myObject is called, the retain count of myObject is more than 1.

Your code is still OK: the responsibility of the containing object is to release ownership when it’s done with it. After [myObject release], myObject won’t be dealloc’ed. Instead, it will be dealloc’ed when anObj releases it.