1  extern void abort(void);
       2  extern void exit(int);
       3  
       4  unsigned int foo(unsigned int a)
       5  {
       6    return ((unsigned char)(a + 1)) * 4;
       7  }
       8  
       9  int main(void)
      10  {
      11    if (foo((unsigned char)~0))
      12      abort ();
      13    exit(0);
      14  }