diff options
Diffstat (limited to 'src/libstrongswan/utils/utils.h')
| -rw-r--r-- | src/libstrongswan/utils/utils.h | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/libstrongswan/utils/utils.h b/src/libstrongswan/utils/utils.h index 1b822dd61..da253cc35 100644 --- a/src/libstrongswan/utils/utils.h +++ b/src/libstrongswan/utils/utils.h @@ -60,6 +60,20 @@ #define BUF_LEN 512 /** + * Build assertion macro for integer expressions, evaluates to 0 + */ +#define BUILD_ASSERT(x) (sizeof(char[(x) ? 0 : -1])) + +/** + * Build time check to assert a is an array, evaluates to 0 + * + * The address of an array element has a pointer type, which is not compatible + * to the array type. + */ +#define BUILD_ASSERT_ARRAY(a) \ + BUILD_ASSERT(!__builtin_types_compatible_p(typeof(a), typeof(&(a)[0]))) + +/** * General purpose boolean type. */ #ifdef HAVE_STDBOOL_H @@ -342,7 +356,8 @@ static inline void *memset_noop(void *s, int c, size_t n) /** * Get the number of elements in an array */ -#define countof(array) (sizeof(array)/sizeof(array[0])) +#define countof(array) (sizeof(array)/sizeof((array)[0]) \ + + BUILD_ASSERT_ARRAY(array)) /** * Ignore result of functions tagged with warn_unused_result attributes |