diff options
| -rw-r--r-- | misc/sys/param.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/misc/sys/param.h b/misc/sys/param.h index 8f4bacbb67..316eddbc43 100644 --- a/misc/sys/param.h +++ b/misc/sys/param.h @@ -102,5 +102,52 @@ #define MIN(a,b) (((a)<(b))?(a):(b)) #define MAX(a,b) (((a)>(b))?(a):(b)) +/* Macros related to the types of variables */ +#define __is_same_type(a, b) \ + __builtin_types_compatible_p(__typeof__(a), __typeof__(b)) +#define __is_array(arr) (!__is_same_type((arr), &(arr)[0])) + +/* Macros for embedding _Static_assert() in expressions */ +#if __STDC_VERSION__ >= 201112L +# define __must_be(expr, msg) ( \ + 0 * (int)sizeof( \ + struct { \ + _Static_assert((expr), msg); \ + char _ISO_C_forbids_a_struct_with_no_members; \ + } \ + ) \ +) +#else +# define __must_be(expr, msg) ( \ + 0 * (int)sizeof( \ + struct { \ + int : (-!(expr)); \ + char _ISO_C_forbids_a_struct_with_no_members; \ + } \ + ) \ +) +#endif +#define __must_be_array(arr) __must_be(__is_array(arr), "Must be an array!") + +/* Macros for array sizes */ +#if defined(__cplusplus) +# if __cplusplus >= 201103L +template<typename T, std::size_t len> + constexpr inline std::size_t + nitems(const T(&)[len]) __THROW + { + return len; + } +# else /* __cplusplus < 201103L */ +template<typename T, std::size_t len> + char + (&__nitems_chararr(const T(&)[len]))[len]; +# define nitems(arr) (sizeof(__nitems_chararr(arr))) +# endif /* __cplusplus < 201103L */ +#else /* !defined(__cplusplus) */ +# define __nitems(arr) (sizeof((arr)) / sizeof((arr)[0])) +# define nitems(arr) (__nitems(arr) + __must_be_array(arr)) +#endif /* !defined(__cplusplus) */ + #endif /* sys/param.h */ |