Checking if an object has been released before sending a message to it

Question

I've only recently noticed a crash in one of my apps when an object tried to message its delegate and the delegate had already been released.

At the moment, just before calling any delegate methods, I run this check:

if (delegate && [delegate respondsToSelector:...]){
   [delegate ...];
}

But obviously this doesn't account for if the delegate isn't nil, but has been deallocated.

Besides setting the object's delegate to nil in the delegate's dealloc method, is there a way to check if the delegate has already been released just incase I no longer have a reference to the object.

Answer 1

No. There is no way to tell whether a variable points to a valid object. You need to structure your program so that this object's delegate isn't going away without letting it know first.