Re: ARC and blocks
Re: ARC and blocks
- Subject: Re: ARC and blocks
- From: David Duncan <email@hidden>
- Date: Thu, 26 Jan 2012 14:34:32 -0800
On Jan 26, 2012, at 1:51 PM, Jan E. Schotsman wrote:
> 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?
> Excuse me if I'm being dumb.
myController retains/copies the block. Then the block retains myController (under ARC __block variables are strong references, so they get retained). Thus you are left with myController retains the block which retains myController.
--
David Duncan
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden