1// include/linux/kernel.h
 2
 3/**
 4 * container_of - cast a member of a structure out to the containing structure
 5 * @ptr:	the pointer to the member.
 6 * @type:	the type of the container struct this is embedded in.
 7 * @member:	the name of the member within the struct.
 8 *
 9 */
10#define container_of(ptr, type, member) ({				\
11	void *__mptr = (void *)(ptr);					\
12	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
13			 !__same_type(*(ptr), void),			\
14			 "pointer type mismatch in container_of()");	\
15	((type *)(__mptr - offsetof(type, member))); })

1struct treeNode {
2  treeNode *left;
3  treeNode *right;
4  void *value;
5};

1struct treeNode {
2  treeNode *left;
3  treeNode *right;
4};
5
6struct valueTemplate {
7  treeNode node;
8  int value;
9}

1#define container_of(ptr, type, member) \
2    (type *)((char *)(ptr) - (char *) &((type *)0)->member)
3
4// 示例用法
5void func(treeNode *node) {
6  valueTemplate *value = container_of(node, struct valueTemplate, node)
7}

1valueTemplate *value = (valueTemplate *)((char *)node  - (char *)&((valueTemplate *)0)->node)