• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: How do I temporary retain self, under ARC?
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: How do I temporary retain self, under ARC?


  • Subject: Re: How do I temporary retain self, under ARC?
  • From: "Stephen J. Butler" <email@hidden>
  • Date: Thu, 17 Jul 2014 23:37:33 -0500

Do you know this code will always run on the main thread? Because you could
fix this from the other side, in the delegate. Use
dispatch_async(dispatch_get_main_queue(), ...) to un-assign the property.
But this won't work if you're on a non-main thread when you call back into
the delegate.


On Thu, Jul 17, 2014 at 10:01 PM, Jens Alfke <email@hidden> wrote:

> Every once in a while I run into a bug in my code that’s triggered by self
> getting dealloced in the middle of a method. It’s usually something like
>         - (void) someMethod {
>                 doSomeStuff;
>                 [self.delegate object: self didSomeStuff: yeah];
>                 doSomeMoreStuff;
>         }
> where it turns out that the delegate method clears its reference to me,
> and that was the last reference, causing self to get dealloced during the
> delegate call, causing doSomeMoreStuff to crash.
>
> Once I’ve identified such a bug, the fix is easy: put a [[self retain]
> autorelease] at the top of the method. Except now I’m using ARC, and I
> can’t find a simple way of doing it. I tried adding
>         __unused id retainedSelf = self;
> but the optimizer recognizes that retainedSelf isn’t used and strips it
> out, making this a no-op. The only thing I’ve found that works is
>         CFRetain((__bridge CFTypeRef)self);
> at the top of the method, and a corresponding CFRelease at the end, but
> this is pretty ugly and could cause leaks if the method returns early.
>
> Am I missing some convenient way of doing this? I looked through the ARC
> docs, at least those I could find, and didn’t see anything relating to this.
>
> —Jens
> _______________________________________________
>
> 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
>
_______________________________________________

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


  • Prev by Date: Re: How do I temporary retain self, under ARC?
  • Next by Date: Re: iBeacons - can 100 different devices be active and seen by one device?
  • Previous by thread: Re: How do I temporary retain self, under ARC?
  • Next by thread: Re: How do I temporary retain self, under ARC?
  • Index(es):
    • Date
    • Thread