UINT_MAX + 1 equals what?

c, portability, standards

Solution

From the standard (C11, 6.2.5/9, emphasis mine):

[...] A computation involving unsigned operands can never overflow, because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type.

If `UINT_MAX` is `10`:

(10 + 1) % (10 + 1) == 0

So, yes, it's safe to assume it's zero.

Problem

What is the defined behavior in C for `UINT_MAX + 1u`? How safe is to assume it is zero?

Original source

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