What's the Difference Between nil and Nil

Question

In Objective C?

Are they really the same thing?

How to test that an object is nil?

Answer 1

nil is the Objective-C constant for a null pointer to an object, Nil is identically defined. In practice, it is has the same value as the C constant NULL. Test for a nil object like this:

if (fooObj == nil)

In my code, I tend to use nil for Objective-C objects and NULL for other C pointers. This is a matter of personal taste - currently nil and NULL are interchangeable for comparison in all existing Objective-C implementations.