Does NSMutableArray's -removeLastObject RELEASE the object?

Question

I'm talking about methods like -removeAllObjects, -removeLastObject, etc for NSMutableArray. The documentation only says that these methods 'remove' the object from the array. Are the removed objects released?

Answer 1

Yes it does. Any remove invokes the release of the removed NSObject.

The NSArray class reference specifies:

Arrays maintain strong references to their contents—in a managed memory environment, each object receives a retain message before its id is added to the array and a release message when it is removed from the array or when the array is deallocated. If you want a collection with different object ownership semantics, consider using CFArray Reference, NSPointerArray, or NSHashTable instead.

Answer 2

Yes, they are released. You can see that the contained object is released by overriding release in an object you've placed in the container. Call the superclass's release method and set a breakpoint on it. You'll see that it's released.

I had originally stated that I thought the objects were auto-released. Turns out I believe I'm wrong about that.