HardenedBSD/include/stdckdint.h
Dag-Erling Smørgrav e6615b1034 include: Implement N2867.
This adds macros for checked addition, subtraction, and multiplication with semantics similar to the builtins gcc and clang have had for years.

Reviewed by:	kib, emaste
Differential Revision:	https://reviews.freebsd.org/D41734
2023-09-07 06:40:14 +00:00

41 lines
1.0 KiB
C

/*-
* Copyright (c) 2023 Dag-Erling Smørgrav
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#ifndef __STDC_VERSION_STDCKDINT_H__
#define __STDC_VERSION_STDCKDINT_H__ 202311L
#include <sys/cdefs.h>
#if __BSD_VISIBLE || __ISO_C_VISIBLE >= 2023
#if __GNUC_PREREQ__(5, 1) || __has_builtin(__builtin_add_overflow)
#define ckd_add(result, a, b) \
(_Bool)__builtin_add_overflow((a), (b), (result))
#else
#define ckd_add(result, a, b) \
_Static_assert(0, "checked addition not supported")
#endif
#if __GNUC_PREREQ__(5, 1) || __has_builtin(__builtin_sub_overflow)
#define ckd_sub(result, a, b) \
(_Bool)__builtin_sub_overflow((a), (b), (result))
#else
#define ckd_sub(result, a, b) \
_Static_assert(0, "checked subtraction not supported")
#endif
#if __GNUC_PREREQ__(5, 1) || __has_builtin(__builtin_mul_overflow)
#define ckd_mul(result, a, b) \
(_Bool)__builtin_mul_overflow((a), (b), (result))
#else
#define ckd_mul(result, a, b) \
_Static_assert(0, "checked multiplication not supported")
#endif
#endif
#endif