Is It Necessary to Set Pointers to nil in Objective-C After release?
Not necessary, but good practice. If you were to inadvertently reference it after release, bad things could happen, but in Objective C there isn't any harm in referencing a nil.
Setting an instance variable to nil is more useful in a multi-threaded application than a single-threaded one, since with multiple threads you can't always guarantee that an instance variable will only be read before it's released.
I generally don't bother in single-threaded applications, unless there's some other compelling reason.
Objective-C is really the same as C with a fancy preprocessor.
Setting a pointer to nil in Objective-C has no effect on what was once pointed to by that pointer.