> On 27 Jul 2016, at 09:33, Trygve Inda <cocoa...@xericdesign.com> wrote: > > > > If the worker thread calls window.imageRep = myResult; it is possible that > the main thread is in the middle of a call like: > > [[window.imageRep] > drawInRect:fromRect:operation:fraction:respectFlipped:hints:] > > So when the setter (called from the worker thread) replaces the old imageRep > with a new one, the old one's retain count goes to zero and it will > disappear. > > I know atomic makes the call safe as far as a vaild value is concerned, but > the main thread could call window.imageRep and get a valid value (because it > is atomic), but before it is able to use this value, the worker thread calls > the setter which causes the imageRep obtained by the main thread to be > released.
No it couldn’t - because when the main thread calls window.imageRep it gets a reference which, whether it assigns it to a variable or just uses it in in a chained call (like you have above with drawInRect:.) is retained by the main thread during the life of that variable or during the call. So it doesn’t matter if the worker thread replaces it after the call to window.imageRep, the main thread’s reference remains valid and usable and is only released when it’s finished with it and only then gets deallocated (if nothing else is referencing it) _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
