Simply record offsetof and container_of

In order to prevent myself from forgetting to record the offsetof and container_of functions of the linux kernel, first define a structure casually

struct node{int a;short b;char c[5];double d;}

show offsetof

//Seek the length of the member MEMBER in the structure type TYPE from the reference position#define offsetof(TYPE, MEMBER) \((size_t)&((TYPE*)0)->MEMBER)

The test data is as follows

container_of

/*ptr: is the member address of a structure variabletype: is the structure typemember: is the name of the member pointed to by the ptr pointer*///Get the memory address of the structure variable from the memory address of the member in the structure variable#define container_of(ptr, type, member) ({ \const typeof( ((type*)0)->member ) *__mptr = (ptr); \(type*)( (char*)__mptr - offsetof(type, member) );})