CODEWITHSUNDEEP
iosobjective-cmemory-leaksobjective-c-blocks
Emanuel
Emanuel

Reputation: 1861

Could someone clarify this block for me?

I was dealing with a problem in which an object used inside a block wouldn't release.

First I had this code:

__block SOMABannerView* bannerView=_bannerView;
self.viewWillDissappearObserver = [center addObserverForName:UIViewWillDissappearNotification object:self.delegate.viewControllerForPresentingModalView queue:mainQueue usingBlock:
    ^(NSNotification *note) {
        [bannerView setAutoReloadEnabled:NO];
     }];

I used __block because it supposedly wouldn't copy and retain the object , but when I was analyzing this code with Instruments I noticed the objects from class SOMABannerView weren't being deallocated, so I changed it to:

self.viewWillDissappearObserver = [center addObserverForName:UIViewWillDissappearNotification object:self.delegate.viewControllerForPresentingModalView queue:mainQueue usingBlock:
    ^(NSNotification *note) {
        [_bannerView setAutoReloadEnabled:NO];
     }];

Which didn't work either, so I ended up using another method from NSNotificationCenter to avoid the block, but still I don't get why the __block was retaining the object, Could somebody clarify this for me? Do i have a wrong concept of __block?

Upvotes: 0

Views: 51

Answers (1)

borrrden
borrrden

Reputation: 33421

It won't retain the object in a non-ARC environment, but it will in an ARC environment. For ARC, use __weak instead of __block.

Source: http://clang.llvm.org/docs/AutomaticReferenceCounting.html#blocks

Upvotes: 3

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