container_of.h File Reference

#include <linux/build_bug.h>
#include <linux/stddef.h>

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Macros
#define	typeof_member(T, m)   typeof(((T*)0)->m)
#define	container_of(ptr, type, member)
#define	container_of_const(ptr, type, member)

Macro Definition Documentation

container_of

#define container_of	(		ptr,
			type,
			member
	)

Value:

    ({              \
    void *__mptr = (void *)(ptr);                   \
    static_assert(__same_type(*(ptr), ((type *)0)->member) ||   \
              __same_type(*(ptr), void),            \
              "pointer type mismatch in container_of()");   \
    ((type *)(__mptr - offsetof(type, member))); })

container_of - cast a member of a structure out to the containing structure @ptr: the pointer to the member. @type: the type of the container struct this is embedded in. @member: the name of the member within the struct.

WARNING: any const qualifier of @ptr is lost. Do not use container_of() in new code.

container_of_const

#define container_of_const	(		ptr,
			type,
			member
	)

Value:

    _Generic(ptr,                           \
        const typeof(*(ptr)) *: ((const type *)container_of(ptr, type, member)),\
        default: ((type *)container_of(ptr, type, member))  \
    )

container_of_const - cast a member of a structure out to the containing structure and preserve the const-ness of the pointer @ptr: the pointer to the member @type: the type of the container struct this is embedded in. @member: the name of the member within the struct.

Always prefer container_of_const() instead of container_of() in new code.

typeof_member

#define typeof_member	(		T,
			m
	)		typeof(((T*)0)->m)