You're assuming `int` is 32-bits. The fact that C implicitly promotes to `int` makes it extremely hard to use the stdint.h typedefs without accidentally making

You're assuming `int` is 32-bits. The fact that C implicitly promotes to `int` makes it extremely hard to use the stdint.h typedefs without accidentally making platform-specific assumptions. uint16_t a, b, c; a = 50000; b = 40000; c = a * b; This simple code may or may not have undefined behavior depending on the target platform. (it's fine for 16-bit int, UB for 32-bit int, and fine again for 64-bit int) Numeric promotion means that it's almost impossible to write code that is correct on multiple platforms with different sizeof(int).