1 /* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */ 2 3 #ifndef _LINUX_BUILD_BUG_H 4 #define _LINUX_BUILD_BUG_H 5 6 #include <linux/compiler.h> 7 8 /* 9 * Force a compilation error if condition is true, but also produce a 10 * result (of value 0 and type int), so the expression can be used 11 * e.g. in a structure initializer (or where-ever else comma expressions 12 * aren't permitted). 13 */ 14 #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) 15 16 /** 17 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied 18 * error message. 19 * @condition: the condition which the compiler should know is false. 20 * 21 * See BUILD_BUG_ON for description. 22 */ 23 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) 24 25 /** 26 * BUILD_BUG_ON - break compile if a condition is true. 27 * @condition: the condition which the compiler should know is false. 28 * 29 * If you have some code which relies on certain constants being equal, or 30 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to 31 * detect if someone changes it. 32 */ 33 #define BUILD_BUG_ON(condition) \ 34 BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) 35 36 /** 37 * BUILD_BUG - break compile if used. 38 * 39 * If you have some code that you expect the compiler to eliminate at 40 * build time, you should use BUILD_BUG to detect if it is 41 * unexpectedly used. 42 */ 43 #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") 44 45 #endif 46