source: CIVL/examples/fairness/fair3.cvl

/* This program has a non-terminating fair execution */
#include <stdio.h>

int x=0, y=0;

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

int main() {
  $proc p1 = $spawn f();
  while (y==0) {
    x=0;
    x=1;
    printf("hi\n");
  }
  $wait(p1);
}