CODEWITHSUNDEEP
objective-ccocoaobjective-c-categoryassociated-object
cfischer
cfischer

Reputation: 24892

Adding ivars to a Category with objc_setAssociatedObject

I'm planning to add to iVars to a category with objc_setAssociatedObject(). However, I'm unsure on when to call objc_removeAssociatedObjects() to get rid of them.

Is there a way the category can know when the object using it has been de-allocated ?

Upvotes: 0

Views: 358

Answers (1)

Martin R
Martin R

Reputation: 539685

If you set an association with

objc_setAssociatedObject(self, &key, otherObject, OBJC_ASSOCIATION_RETAIN);
// or OBJC_ASSOCIATION_RETAIN_NONATOMIC

then otherObject is automatically released when self is deallocated. (At least if you use ARC, but I think this is also correct with manual reference counting.)

So you don't have to call objc_removeAssociatedObjects() explicitly, unless you want to get rid of the added objects before the main object is deallocated.

Upvotes: 2

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