Absolute value of NSInteger

Question

Referring to Convert to absolute value in Objective-C I\'m wondering if there are functions for NS typedefed types. Or is abs(NSInteger) okay? Is it architecture-sa

Answer 1

Use ABS() macro, which is defined in NSObjCRuntime.h, it is architecture-safe.

Answer 2

You can use Foundation’s ABS() macro:

NSInteger a = 5;
NSInteger b = -5;
NSLog(@"%ld %ld", ABS(a), ABS(b));

Answer 3

While the two posted answers are absolutely correct about using the ABS() macro, it should certainly be noted that NSIntegerMin, whose true absolute value can not be represented as an NSInteger returns itself when the ABS() function is called.

Presuming a 64-bit system:

NSLog(@"ld", ABS(NSIntegerMin)); 
// prints: -9223372036854775808

NSLog(@"%ld", ABS(NSIntegerMin + 1)); 
// prints: 9223372036854775807, which == NSIntegerMax

The same results will happen on a 32-bit system, but the numbers will be +2147483647 and -2147483648