Unsigned integer arithmetic in C ($x\mathrm{op}y(\mathrm{mod}{2}^w)$)

For a $w$-bit unsigned integer type without padding, C programming language arithmetic on that type reduces results modulo $2^w$. In particular, subtracting two uint32_t timestamps gives their modular difference when that subtraction is evaluated in the 32-bit unsigned type. Integer promotions must be checked for narrower types or unusual implementations. Signed integer overflow has different rules and must not be treated as the same operation.^[ref]