Re: integer divided by zero

On Fri, 25 Apr 2025 12:05:13 -0700, Keith Thompson wrote:

Thiago Adams writes:

Does anyone know of any platform where integer division by zero
returns a number, or in other words, where it's not treated as an
error? I'm asking because division by zero is undefined behaviour, but
I think division by a constant zero should be a constraint instead.

>
Division by a constant zero is a constraint violation in a context that
requires a constant expression.
>
I wrote this quick and dirty program:
>
#include <stdio.h>
#include <time.h>
int main(void) {
   int one = time(NULL) / 1000000000;
   int zero = one - 1;
   int ratio = one / zero;
   printf("%d\n", ratio);

in math
1/0 has to be +infinite ( for approximation +INT_MAX for C?)
but should be one error if one want one infinite array long
as in "int a[1/0]" or want to do infinite/0 infinite-inifinite
infinite/infinite ecc could be ok if one make infinite+infiniteinfinite, infinite * infinite = infinite ecc

}
>
It's not portable, but on the systems where I've tried it it sets
one to 1 and zero to 0 in a way that the compiler can't detect,
so the division won't be optimized away.  (At least, it does so if
you run it between 2001 and 2286.)
>
On x86_64, it dies with a floating point exception.
>
On aarch64, it prints 0.