linux 内核链表的应用

内核版本：kernel 3.0.1

#include <stdio.h>
#include <stdlib.h>
#include <sys/queue.h>

struct ElemType
{
        int num;
        char *ptr;
        LIST_ENTRY(ElemType) entries;
};

LIST_HEAD(List, ElemType);

static struct List gListHead;

// linux自带的LIST_END用不了，可能是要什么头文件，或者编译时候需要某个库支持，但是我暂时还没找到驾驭LIST_END的方法。
// （若有哪位大虾知道还请告知）
// 下面是我自己模仿linux的LIST_END函数头写的。
struct ElemType* LIST_END(struct List *list)
{
        struct ElemType *recv = NULL;
        struct ElemType *elem = NULL;
        LIST_FOREACH(elem, list, entries)
        {
                if (elem && elem->entries.le_next == NULL)
                {
                        recv = elem;
                }
        }
        return recv;
}

// 尾部插入。linux没有提供（反正我没找到，若有哪位大虾知道还请告知）尾部插入的方法，只能自己实现了。
//void LIST_INSERT_TAIL(struct List *list, struct ElemType *elem, LIST_ENTRY name) // LIST_ENTRY不能通过编译，why?
void LIST_INSERT_TAIL(struct List *list, struct ElemType *elem)
{
        struct ElemType *tail = LIST_END(list);
        if (tail)
        {
                LIST_INSERT_AFTER(tail, elem, entries);
        }
        else
        {
                LIST_INSERT_HEAD(list, elem, entries);
        }
}

int main()
{
        LIST_INIT(&gList);

        struct ElemType *elem1 = (struct ElemType *)malloc(sizeof(struct ElemType));
        struct ElemType *elem2 = (struct ElemType *)malloc(sizeof(struct ElemType));
        struct ElemType *elem3 = (struct ElemType *)malloc(sizeof(struct ElemType));
        elem1->num = 11;
        elem2->num = 22;
        elem3->num = 33;

        // insert in the head
        LIST_INSERT_HEAD(&gList, elem1, entries);
        LIST_INSERT_HEAD(&gList, elem2, entries);
        LIST_INSERT_HEAD(&gList, elem3, entries);

        // insert in the tail
        //LIST_INSERT_TAIL(&gList, elem1);
        //LIST_INSERT_TAIL(&gList, elem2);
        //LIST_INSERT_TAIL(&gList, elem3);

        struct ElemType *elem;
        // 采用 for 循环遍历
        for (elem = gList.lh_first; elem; elem = elem->entries.le_next)
        {
                printf("using for, num = %d\n", elem->num);
                if (elem->num == 22)
                {
                        LIST_REMOVE(elem, entries);
                        free(elem);
                        //elem->num = 99;
                }
        }

        // 采用 LIST_FOREACH 遍历
        LIST_FOREACH(elem, &gList, entries)
        {
                printf("using LIST_FOREACH, num = %d\n", elem->num);
                //if (elem->num == 33)
                {
                        LIST_REMOVE(elem, entries);
                        free(elem);
                }
        }

        LIST_FOREACH(elem, &gList, entries)
        {
                printf("using LIST_FOREACH, num = %d\n", elem->num);
        }

        return 0;
}