include/linux/args.h

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

File Facts

System
Linux kernel
Corpus path
include/linux/args.h
Extension
.h
Size
1021 bytes
Lines
29
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_ARGS_H
#define _LINUX_ARGS_H

/*
 * How do these macros work?
 *
 * In __COUNT_ARGS() _0 to _15 are just placeholders from the start
 * in order to make sure _n is positioned over the correct number
 * from 15 to 0 (depending on X, which is a variadic argument list).
 * They serve no purpose other than occupying a position. Since each
 * macro parameter must have a distinct identifier, those identifiers
 * are as good as any.
 *
 * In COUNT_ARGS() we use actual integers, so __COUNT_ARGS() returns
 * that as _n.
 */

/* This counts to 15. Any more, it will return 16th argument. */
#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _n, X...) _n
#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)

/* Concatenate two parameters, but allow them to be expanded beforehand. */
#define __CONCAT(a, b) a ## b
#define CONCATENATE(a, b) __CONCAT(a, b)

#endif	/* _LINUX_ARGS_H */

Annotation

Implementation Notes