clang/lib/Headers/stdckdint.h

/*===---- stdckdint.h - Standard header for checking integer----------------===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 *===-----------------------------------------------------------------------===
 */

#ifndef __STDCKDINT_H
#define __STDCKDINT_H

/* If we're hosted, fall back to the system's stdckdint.h. FreeBSD, for
 * example, already has a Clang-compatible stdckdint.h header.
 *
 * The `stdckdint.h` header requires C 23 or newer.
 */
#if __STDC_HOSTED__ && __has_include_next(<stdckdint.h>)
#include_next <stdckdint.h>
#else

/* C23 7.20.1 Defines several macros for performing checked integer arithmetic*/

#define __STDC_VERSION_STDCKDINT_H__ 202311L

// Both A and B shall be any integer type other than "plain" char, bool, a bit-
// precise integer type, or an enumerated type, and they need not be the same.

// R shall be a modifiable lvalue of any integer type other than "plain" char,
// bool, a bit-precise integer type, or an enumerated type. It shouldn't be
// short type, either. Otherwise, it may be unable to hold two the result of
// operating two 'int's.

// A diagnostic message will be produced if A or B are not suitable integer
// types, or if R is not a modifiable lvalue of a suitable integer type or R
// is short type.
#define ckd_add(R, A, B) __builtin_add_overflow((A), (B), (R))
#define ckd_sub(R, A, B) __builtin_sub_overflow((A), (B), (R))
#define ckd_mul(R, A, B) __builtin_mul_overflow((A), (B), (R))

#endif /* __STDC_HOSTED__ */
#endif /* __STDCKDINT_H */