Question

- (void)dealloc {
    [super dealloc];
    [receivedData release]; receivedData = nil;
}

or

- (void)dealloc {
    [receivedData release]; receivedData = nil;
    [super dealloc];
}

Answer 1

Yes, it absolutely maters when [super dealloc] is called. Once [super dealloc] is called, you can no longer rely on the NSObject (or whatever your root class is) machinery to function properly. Afterall, your super-class’ -dealloc method should call its superclass’ etc. until the root class’ -dealloc method is called. At that point, everything that these classes allocate to do their job is potentially gone and you’re in undefined territory if you try to use any of it.

Your -dealloc method should always look like

- (void)dealloc
{
   // release my own stuff first

   [super dealloc];
}