Le 26 janv. 2012 à 22:51, Jan E. Schotsman a écrit :

> Hello,
> 
> This code is given in the "Transitioning to ARC Release Notes" as an example 
> of accomodating blocks in an ARC environment:
> 
> __block MyViewController *myController = [[MyViewController alloc] init…];
> // ...
> myController.completionHandler =  ^(NSInteger result) {
>    [myController dismissViewControllerAnimated:YES completion:nil];
>    myController = nil;
> };
> 
> Supposedly this avoids a retain cycle. But where is the cycle? At least two 
> objects are needed for a cycle. What is the second one?

The first object if myController.
The second object is the block.

myController retains the block.
the block retains myController.

You have your retain cycle.

-- Jean-Daniel





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