这是在Linux下面最常用的一个统一的链表结构，Linux就是用这个结构将所有的Driver、Device什么的都分别串在一起。我觉得写得非常好，大家来看一看。
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#ifndef _LINUX_LIST_H#define _LINUX_LIST_H
#ifdef __KERNEL__
struct list_head { struct list_head *next, *prev;};
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) / struct list_head name = LIST_HEAD_INIT(name)
#define INIT_LIST_HEAD(ptr) do { / (ptr)->next = (ptr); (ptr)->prev = (ptr); /} while (0)
/* * Insert a new entry between two known consecutive entries. * This is only for internal list manipulation where we know the prev/next entries already! */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;}
/* * list_add - add a new entry * Insert a new entry after the specified head. * This is good for implementing stacks. */static __inline__ void list_add(struct list_head *new, struct list_head *head){ __list_add(new, head, head->next);}
/* * list_add_tail - add a new entry * Insert a new entry before the specified head. * This is useful for implementing queues. */static __inline__ void list_add_tail(struct list_head *new, struct list_head *head){ __list_add(new, head->prev, head);}
/* * Delete a list entry by making the prev/next entries point to each other. * This is only for internal list manipulation where we know the prev/next entries already! */static __inline__ void __list_del(struct list_head * prev, struct list_head * next){ next->prev = prev; prev->next = next;}
/* * list_del - deletes entry from list. * Note: list_empty on entry does not return true after this, the entry is in an undefined state. */static __inline__ void list_del(struct list_head *entry){ __list_del(entry->prev, entry->next);}
/** * list_del_init - deletes entry from list and reinitialize it. */static __inline__ void list_del_init(struct list_head *entry){ __list_del(entry->prev, entry->next); INIT_LIST_HEAD(entry);}
/* * list_empty - tests whether a list is empty */static __inline__ int list_empty(struct list_head *head){ return head->next == head;}
/** * list_splice - join two lists * @list: the new list to add. * @head: the place to add it in the first list. */static __inline__ void list_splice(struct list_head *list, struct list_head *head){ struct list_head *first = list->next;
if (first != list) { struct list_head *last = list->prev; struct list_head *at = head->next; first->prev = head; head->next = first; last->next = at; at->prev = last; }}
/** * list_entry - get the struct for this entry * @ptr: the &struct list_head pointer. * @type: the type of the struct this is embedded in. * @member: the name of the list_struct within the struct. */#define list_entry(ptr, type, member) / ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
/** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. */#define list_for_each(pos, head) / for (pos = (head)->next; pos != (head); pos = pos->next)
#endif /* __KERNEL__ */
#endif
补充一下——给看不懂的同志。
它是个双向的循环链表，这个链表可以用到任何结构里，比如：
struct kk { type1 data1; type2 data2; ...... struct list_head list; typen datan;}
再有一个链表头：LIST_HEAD(kk_list)
然后调用链表函数的时候是这样的，比如要把一个新结点kk_node加到链表尾
list_add_tail ( &(kk_node.list), &kk_list );
只是把结点中的list成员加进去，要获得某个包含list_head节点的结构指针
struct kk *p = list_entry( p, kk, list );
当调用delete操作时，仅仅是把结点从链表中去掉，并不真正释放结点所占用的空间，因为这是个通用结构嘛，分配释放由用户自己管理。
