From Apple docs:Use an NSNull
The NSNull instance is semantically equivalent to nil, however it is also important to appreciate that it is not equal to nil.
why do you want to do this? You can ask an array for it's length, so you don't need a special element to tell you you're at the end.
-Lee
I am building an extension to an existing library for which I don't have the original source. Inside that library, there is a class that has a function that accepts variable arguments, with nil at the end.