| /* SPDX-License-Identifier: GPL-2.0 */ |
| |
| #ifndef _LINUX_ARGS_H |
| #define _LINUX_ARGS_H |
| |
| /* |
| * How do these macros work? |
| * |
| * In __COUNT_ARGS() _0 to _12 are just placeholders from the start |
| * in order to make sure _n is positioned over the correct number |
| * from 12 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 */ |
