When does a weak reference get updated to nil in Objective-C? [duplicate]

Answer 1

I think this is because when you get into the if statement with weakOne will increment the retain count in autorelease pool; therefore, the weak pointer will not be zero until the autorelease pool drained.

 // Try this
NSObject *strongOne = [[NSObject alloc] init];
NSObject * __weak weakOne = strongOne; //count 1
@autoreleasepool {

    if (weakOne) { 
        NSLog(@"weakOne is not nil."); //count 2
    } else {
        NSLog(@"weakOne is nil.");
    }

    strongOne = nil; // count 1

    if (weakOne) { 
        NSLog(@"weakOne is not nil.");
    } else {
        NSLog(@"weakOne is nil.");
    }

} // count 0, therefore the weakOne become nil

if (weakOne) {
    NSLog(@"weakOne is not nil.");
} else {
    NSLog(@"weakOne is nil.");
}