source: CIVL/examples/fairness/unfair2.cvl

/* This program has no non-terminating fair execution */
#include <stdio.h>

int x=0, y=0;

void f() {
  $when (x==0) x=1;
  printf("bye\n");
  y=1;
}

int main() {
  $proc p1 = $spawn f();
  while (y==0) {
    printf("hi\n");
  }
  $wait(p1);
}