1  extern void abort(void);
       2  extern void exit(int);
       3  
       4  int *c;
       5  
       6  void bar(int b)
       7  {
       8    if (*c != 1 || b != 2)
       9      abort();
      10  }
      11  
      12  void foo(int a, int b)
      13  {
      14    c = &a;
      15    bar(b);
      16  }
      17  
      18  int main()
      19  {
      20    foo(1, 2);
      21    exit(0);
      22  }