1   
    2   void end(void)
    3   {
    4       printf("2");
    5   }
    6   
    7   int main()
    8   {
    9       if (Fork() == 0)
   10         atexit(end);
   11       if (Fork() == 0)
   12         printf("0");
   13       else
   14         printf("1");
   15       exit(0);
   16   }