Question

It seems to be

if(myObj == (typeOfMyObj *) kCFNull){
 //myObj is null
}

and

if(myObj == (typeOfMyObj *) [NSNull null]){
 //myObj is null
}

produce the same result.

Is this always the case? I’m developing an iOS 5 application.

Thanks!

Answer 1

It appears none of Apple’s docs state that NSNull and CFNullRef are toll-free-bridged, but it nevertheless seems that they are and have been since CFNullRef was introduced in Mac OS X 10.2. NSNull was available starting with Mac OS X 10.0. In the end, they are both really just sentinel values that serve as a distinguished NULL object.

There’s probably a way for your code to avoid depending on kCFNull == [NSNull null], but if you can’t for some reason, then I wouldn’t worry about it too much.