linux中的部分宏

链表

struct list_head{
struct list_head *next,*prev;}

链表声明

#define LIST_HEAD_INIT(name) {&(name),&(name)}
================================================
1.静态初始化
#define LIST_HEAD(name)
struct list_head name = LIST_HEAD_INIT(name)
=================================================
LIST_HEAD(list_name);
==>
struct list_head list_name = LIST_HEAD_INIT(name);
==>
struct list_head list_name = {&(list_name), &(list_name)};
//相当于给一个结构声明加初始化，让list_name的成员变量
//【next,prev】 = {&(list_name), &(list_name)}

2.运行时初始化
stattic inline void INIT_LIST_HEAD(struct list_head *list)
{
list->next = list;
list->prev = list;
}

链表是否为空

static inline int list_empty(const struct list_head* head)
{
return head->next == head;
}

链表插入

1.插入head后
static inline void list_add(struct list_head* new, struct list_head* head)
{
__list_add(new, head, head->next);
}
2.插入head->prev后
static inline void list_add_tail(struct list_head* new, struct list_head* head)
{
__list_add(new, head->prev, head);
}

删除

static inline void list_replace_init(struct list_head *old, struct list_head *new)
{
list_replace(old,new);
INIT_LIST_HEAD(old);
}

遍历

#define list_entry(ptr, type, member) \
container_of(ptr, type, member)

#define container_of(ptr, type, member) \
{\
const typeof( ((type *)0)->member ) *__mptr = (ptr);\
(type *)( (char *)__mptr - offsetof(type,member) ); \
}

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

遍历链表：
宏：list_for_each()
#define list_for_each(pos, head) \
for (pos = (head)->next, prefetch(pos->next); \
pos != (head); \
pos = pos->next, prefetch(pos->next))

pos是迭代指针，指向当前访问的链表头。
head是要访问的链表的链表头。

结合list_entry使用，就可以访问链表头所在元素了。
list_for_each(p,&elem_list){
f = list_entry(p, struct elem, list);
}

更简单使用：
宏：list_for_each_entry(pos,head,member)