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Diffstat (limited to '')
-rw-r--r-- | ccan/ccan/array_size/array_size.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/ccan/ccan/array_size/array_size.h b/ccan/ccan/array_size/array_size.h new file mode 100644 index 0000000..0ca422a --- /dev/null +++ b/ccan/ccan/array_size/array_size.h @@ -0,0 +1,26 @@ +/* CC0 (Public domain) - see LICENSE file for details */ +#ifndef CCAN_ARRAY_SIZE_H +#define CCAN_ARRAY_SIZE_H +#include "config.h" +#include <ccan/build_assert/build_assert.h> + +/** + * ARRAY_SIZE - get the number of elements in a visible array + * @arr: the array whose size you want. + * + * This does not work on pointers, or arrays declared as [], or + * function parameters. With correct compiler support, such usage + * will cause a build error (see build_assert). + */ +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + _array_size_chk(arr)) + +#if HAVE_BUILTIN_TYPES_COMPATIBLE_P && HAVE_TYPEOF +/* Two gcc extensions. + * &a[0] degrades to a pointer: a different type from an array */ +#define _array_size_chk(arr) \ + BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(typeof(arr), \ + typeof(&(arr)[0]))) +#else +#define _array_size_chk(arr) 0 +#endif +#endif /* CCAN_ALIGNOF_H */ |