1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_BUILD_BUG_H
3 #define _LINUX_BUILD_BUG_H
5 #include <linux/compiler.h>
8 #define BUILD_BUG_ON_ZERO(e) (0)
9 #else /* __CHECKER__ */
11 * Force a compilation error if condition is true, but also produce a
12 * result (of value 0 and type int), so the expression can be used
13 * e.g. in a structure initializer (or where-ever else comma expressions
16 #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
17 #endif /* __CHECKER__ */
19 /* Force a compilation error if a constant expression is not a power of 2 */
20 #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \
21 BUILD_BUG_ON(((n) & ((n) - 1)) != 0)
22 #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \
23 BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
26 * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
27 * expression but avoids the generation of any code, even if that expression
30 #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
33 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
35 * @condition: the condition which the compiler should know is false.
37 * See BUILD_BUG_ON for description.
39 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
42 * BUILD_BUG_ON - break compile if a condition is true.
43 * @condition: the condition which the compiler should know is false.
45 * If you have some code which relies on certain constants being equal, or
46 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
47 * detect if someone changes it.
49 #define BUILD_BUG_ON(condition) \
50 BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
53 * BUILD_BUG - break compile if used.
55 * If you have some code that you expect the compiler to eliminate at
56 * build time, you should use BUILD_BUG to detect if it is
59 #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
62 * static_assert - check integer constant expression at build time
64 * static_assert() is a wrapper for the C11 _Static_assert, with a
65 * little macro magic to make the message optional (defaulting to the
66 * stringification of the tested expression).
68 * Contrary to BUILD_BUG_ON(), static_assert() can be used at global
69 * scope, but requires the expression to be an integer constant
70 * expression (i.e., it is not enough that __builtin_constant_p() is
73 * Also note that BUILD_BUG_ON() fails the build if the condition is
74 * true, while static_assert() fails the build if the expression is
77 #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
78 #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
80 #endif /* _LINUX_BUILD_BUG_H */