You get this warning if you compile on OS X (64-bit), because on that platform NSInteger is defined as long and is a 64-bit integer. The %i format, on the other hand, is for int, which is 32-bit. So the format and the actual parameter do not match in size. Since NSInteger is 32-bit or … Read more
Ta da: NSInteger myInteger = 42; int myInt = (int) myInteger; NSInteger is nothing more than a 32/64 bit int. (it will use the appropriate size based on what OS/platform you’re running)
If the string is a human readable representation of a number, you can do this: NSInteger myInt = [myString intValue];
You usually want to use NSInteger when you don’t know what kind of processor architecture your code might run on, so you may for some reason want the largest possible integer type, which on 32 bit systems is just an int, while on a 64-bit system it’s a long. I’d stick with using NSInteger instead … Read more