最终建立的链表结构如图,下面看一下insert操作,经过宏替换后代码如下  
  
struct QUEUE_ITEM *ins_item;  
ins_item=malloc(sizeof(ins_item));  
ins_item->value=100;  
  
do {  
    (ins_item)->entries.tqe_prev = (item)->entries.tqe_prev;  
    (ins_item)->entries.tqe_next = (item);  
    //这句话体现了TAILQ的特色,tqe_prev是前一个元素的下个元素地址,  
    //所以正好应该是当前插入item的地址  
    *(item)->entries.tqe_prev = (ins_item);  
    (item)->entries.tqe_prev = &(ins_item)->entries.tqe_next;  
} while (0);

总结:TAILQ的最大特点就是每个entry的二级指针tqe_prev其存放的是前一个元素的下个元素地址,呵呵,听起来都很拗口
我现在就是不知道为什么linux的queue.h只有建立tailq的宏定义而缺少所有的access method,初涉linux c编程,请大家指教

附经过宏替换后的所有代码

#include "stdio.h"
#include "stdlib.h"
struct QUEUE_ITEM{
	int value;
	struct {
		struct QUEUE_ITEM *tqe_next;
		struct QUEUE_ITEM **tqe_prev;
	}entries;
};
struct {
	struct QUEUE_ITEM *tqh_first;
	struct QUEUE_ITEM **tqh_last;
}queue_head;

int main(int argc,char **argv){
	struct QUEUE_ITEM *item;
	struct QUEUE_ITEM *tmp_item;

	do {
		(&queue_head)->tqh_first = NULL;
		(&queue_head)->tqh_last = &(&queue_head)->tqh_first;
	} while (0);

	int i=0;
	for(i=5;i<10;i+=2){
		item=malloc(sizeof(item));
		item->value=i;
		do {
			(item)->entries.tqe_next = NULL;
			//首次执行相当于item->entries.tqe_prev=&(&queue_head)->tqh_first
			//以后执行相当于是(item)->entries.tqe_prev=&(前一个item)->entries.tqe_next;
			(item)->entries.tqe_prev = (&queue_head)->tqh_last;
			//首次执行相当于(&queue_head)->tqh_first=item
			//以后执行相当于是(前一个item)->entries.tqe_next=当前item
			*(&queue_head)->tqh_last = (item);
			(&queue_head)->tqh_last = &(item)->entries.tqe_next;
		} while (0);
	}

	struct QUEUE_ITEM *ins_item;
	ins_item=malloc(sizeof(ins_item));

	ins_item->value=100;
	do {
		(ins_item)->entries.tqe_prev = (item)->entries.tqe_prev;
		(ins_item)->entries.tqe_next = (item);
		*(item)->entries.tqe_prev = (ins_item);
		(item)->entries.tqe_prev = &(ins_item)->entries.tqe_next;
	} while (0);

	tmp_item=((&queue_head)->tqh_first);
	printf("first element is %d\n",tmp_item->value);

	tmp_item=((tmp_item)->entries.tqe_next);
	printf("next element is %d\n",tmp_item->value);

	tmp_item=((tmp_item)->entries.tqe_next);
	printf("next element is %d\n",tmp_item->value);

	tmp_item=((tmp_item)->entries.tqe_next);
	printf("next element is %d\n",tmp_item->value);

}