在Linux中,list.h文件定义了双向链表结构的相关数据结构和操作。其结构定义如下:
struct list_head {
struct list_head *prev, *next;
};
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) \
struct list_head name = LIST_HEAD_INIT(name)
static inline void INIT_LIST_HEAD(struct list_head *list) {
list->next = list;
list->prev = list;
}
static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next) {
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}
static inline void list_add(struct list_head *new, struct list_head *head) {
__list_add(new, head, head->next);
}
static inline void list_add_tail(struct list_head *new, struct list_head *head) {
__list_add(new, head->prev, head);
}
static inline void __list_del(struct list_head *prev, struct list_head *next) {
next->prev = prev;
prev->next = next;
}
static inline void list_del(struct list_head *entry) {
__list_del(entry->prev, entry->next);
entry->next = NULL;
entry->prev = NULL;
}
#define container_of(ptr, type, member) ({ \
const typeof(((type *)0)->member) *__mptr = (ptr); \
(type *)((char *)__mptr - offsetof(type, member)); })
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
这里定义了一个双向链表节点struct list_head
,包含了指向前一个节点和后一个节点的指针。另外,还定义了一些操作函数,比如初始化链表头、向链表中添加节点、从链表中删除节点等操作。此外,还定义了两个宏container_of
和list_entry
,用于获取包含链表节点的结构体。