C语言双向循环链表api（源自gluster源码），基本的操作如增加、删除和遍历等。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*定义表头*/
struct list_head {
    struct list_head *next;
    struct list_head *prev;
};

/*表头初始化*/
#define INIT_LIST_HEAD(head) do {          \
        (head)->next = (head)->prev = head; \
    } while (0)

/*增加*/
static inline void
list_add (struct list_head *new, struct list_head *head)
{
    new->prev = head;
    new->next = head->next;

    new->prev->next = new;
    new->next->prev = new;
}

/*删除*/
static inline void
list_del (struct list_head *old)
{
    old->prev->next = old->next;
    old->next->prev = old->prev;

    old->next = (void *)0xbabebabe;
    old->prev = (void *)0xcafecafe;
}

/*判断链表是否为空*/
static inline int
list_empty (struct list_head *head)
{
    return (head->next == head);
}

#define list_entry(ptr, type, member)                  \
    ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))

#define list_for_each(pos, head)                                        \
    for (pos = (head)->next; pos != (head); pos = pos->next)

/*遍历，关于list_for_each_entry，百度*/
#define list_for_each_entry(pos, head, member)              \
    for (pos = list_entry((head)->next, typeof(*pos), member);  \
        &pos->member != (head);                    \
        pos = list_entry(pos->member.next, typeof(*pos), member))

/*例：先定义一个结构体*/
typedef struct student
{                 
    int num;        //学号
    int score;      //分数
    char name[20];
    struct list_head student_list;
}STU;

STU *head=NULL;

int main(void)
{
    STU *new=NULL;

    new = (STU *)malloc(sizeof(STU));
    bzero(new, sizeof(STU));
    new->num = 8;
    new->score = 8;
    strcpy(new->name, "8888");
    /*链表初始化*/
    if(head == NULL)
    {
        // head = (STU *)malloc(sizeof(STU));
        // bzero(head, sizeof(STU));
        head = new;
        INIT_LIST_HEAD(&head->student_list);
    }
    else
    {
        list_add(&new->student_list, &head->student_list);
    }