You're right that this test would be UB for signed integers. See here for that in action, as well as one way to test it that does work: https://godbolt.org/z/s

You're right that this test would be UB for signed integers. See here for that in action, as well as one way to test it that does work: https://godbolt.org/z/sca6hxer4 https://godbolt.org/z/sca6hxer4 If you're on C23, uercker's advice to use these standardized functions is the best, of course.