1/* SPDX-License-Identifier: GPL-2.0 */ 2 3#ifndef _LINUX_ARGS_H 4#define _LINUX_ARGS_H 5 6/* 7 * How do these macros work? 8 * 9 * In __COUNT_ARGS() _0 to _12 are just placeholders from the start 10 * in order to make sure _n is positioned over the correct number 11 * from 12 to 0 (depending on X, which is a variadic argument list). 12 * They serve no purpose other than occupying a position. Since each 13 * macro parameter must have a distinct identifier, those identifiers 14 * are as good as any. 15 * 16 * In COUNT_ARGS() we use actual integers, so __COUNT_ARGS() returns 17 * that as _n. 18 */ 19 20/* This counts to 12. Any more, it will return 13th argument. */ 21#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n 22#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 23 24/* Concatenate two parameters, but allow them to be expanded beforehand. */ 25#define __CONCAT(a, b) a ## b 26#define CONCATENATE(a, b) __CONCAT(a, b) 27 28#endif /* _LINUX_ARGS_H */ 29