Question

I have property:

@property(nonatomic, retain) NSMutableArray *myvar;

First case:

    myvar = [[NSMutableArray alloc] init];
    NSLog(@retainCount: %i:", [myvar  retainCount]);

outputs:

retainCount: 1

Second case:

    self.myvar = [[NSMutableArray alloc] init];
    NSLog(@retainCount: %i:", [self.myvar  retainCount]);

outputs:

retainCount: 2

My question is: why in the second case retain value is 2 ?

Answer 1

+1 because you alloc/init‘d it
+1 because self.myvar retains it (as set out in your property declaration)

if you autorelease after alloc/init, it will go back down to 1… then if you set self.myvar to nil, it will hit 0 (if nothing else has retained it in the meantime)

But as vikingosegundo has said, you don’t want to be messing with retain counts. The OS determines when to knock them back down, so you can’t use them as a reliable measure of state.