// Clause: 6.5.9 — Relational comparisons of pointers are defined only for pointers into the same array object (or one-past).
// Members of a struct do not constitute an array object; comparing &s.x < &s.y is undefined behavior.
#include <stdio.h>
struct S { int x; int y; };
int main(void){
    struct S s = {1,2};
    int r = &s.x < &s.y; // UB
    printf("%d\n", r);
    return 0;
}