1 extern void abort (void); 2 3 struct delay_block { 4 struct delay_block *succ; 5 }; 6 7 static struct delay_block Timer_Queue; 8 time_enqueue(struct delay_block * d)9struct delay_block* time_enqueue (struct delay_block *d) 10 { 11 struct delay_block *q = Timer_Queue.succ; 12 d->succ = (void *)0; 13 return Timer_Queue.succ; 14 } 15 main(void)16int main(void) 17 { 18 Timer_Queue.succ = &Timer_Queue; 19 if (time_enqueue (&Timer_Queue) != (void*)0) 20 abort (); 21 return 0; 22 } 23 24