How do I test if a primitive in Objective-C is nil?

Question

I\'m doing a check in an iPhone application -

int var;
if (var != nil)

It works, but in X-Code this is generating a warning \"comparison b

Answer 1

if (var) {
    ...
}

Welcome to the wonderful world of C. Any value not equal to the integer 0 or a null pointer is true.

But you have a bug: ints cannot be null. They're value types just like in Java.

If you want to "box" the integer, then you need to ask it for its address:

int can_never_be_null = 42; // int in Java
int *can_be_null = &can_never_be_null; // Integer in Java
*can_be_null = 0; // Integer.set or whatever
can_be_null = 0;  // This is setting "the box" to null,
                  //  NOT setting the integer value