extern integer $int$;

interface ishadow {
  in void e(integer g, integer p);
  in void f(out integer p);
  in void b(out integer x);
   behaviour {
    on e: {}
    on f: {}
    on b: {}
  }
}

component data_shadow_port {
  provides ishadow p;
  behaviour {
    bool x = false;
    integer g = $-1$;
    on p.e(a, p): g = a;
    on p.f(q): q = g;
    on p.b(x <- g): blocking p.reply();
  }
}