memory - iPhone - dealloc - Release vs. nil

Question

Wondering if someone with experience could possibly explain this a bit more. I have seen examples of...

  [view release];

  view = nil;  

....inside the (void) dealloc.

What is the difference and is one better then the other? What is the best way?

When doing retainCount testing I have personally seen nil drop a count from 3 to 0 for me, but release only drops it from 3 to 2.

Answer 1

What you have seen is probably these:

1) [foo release];
2) self.bar = nil;
3) baz = nil;

1. Is releasing the object, accessing it through the instance variable foo. The instance variable will become a dangling pointer. This is the preferred method in dealloc.

2. Is assigning nil to a property bar on self, that will in practice release whatever the property is currently retaining. Do this if you have a custom setter for the property, that is supposed to cleanup more than just the instance variable backing the property.

3. Will overwrite the pointer baz referencing the object with nil, but not release the object. The result is a memory leak. Never do this.