include/linux/container_of.h

Source file repositories/reference/linux-study-clean/include/linux/container_of.h

File Facts

System
Linux kernel
Corpus path
include/linux/container_of.h
Extension
.h
Size
1449 bytes
Lines
42
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _LINUX_CONTAINER_OF_H
#define _LINUX_CONTAINER_OF_H

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

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

/**
 * 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.
 */
#define container_of(ptr, type, member) ({				\
	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_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.
 */
#define container_of_const(ptr, type, member)				\
	_Generic(ptr,							\
		const typeof(*(ptr)) *: ((const type *)container_of(ptr, type, member)),\
		default: ((type *)container_of(ptr, type, member))	\
	)

#endif	/* _LINUX_CONTAINER_OF_H */

Annotation

Implementation Notes