void  main(int  argc, char* argv[])
{
     max_iteration = abs(atoi(argv[1]));
     iter = 1;
     if (setjmp(Main) == 0)
          Ping();
     if (setjmp(Main) == 0)
          Pong();
     longjmp(PointA, 1);      
}

void  Ping(void)
{
     if (setjmp(PointA) == 0)
          longjmp(Main, 1);
     while (1) {
          printf("%3d : Ping-", iter);
          if (setjmp(PointA) == 0)
               longjmp(PointB, 1);
     }
}

void  Pong(void)
{
     if (setjmp(PointB) == 0)
          longjmp(Main, 1);
     while (1) {
          printf("Pong\n");
          iter++;
          if (iter > max_iteration)
               exit(0);
          if (setjmp(PointB) == 0)
               longjmp(PointA, 1);
     }
}