xref: /freebsd/contrib/llvm-project/clang/lib/Headers/stdckdint.h (revision 5f757f3ff9144b609b3c433dfd370cc6bdc191ad)
1 /*===---- stdckdint.h - Standard header for checking integer----------------===
2  *
3  * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4  * See https://llvm.org/LICENSE.txt for license information.
5  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6  *
7  *===-----------------------------------------------------------------------===
8  */
9 
10 #ifndef __STDCKDINT_H
11 #define __STDCKDINT_H
12 
13 /* If we're hosted, fall back to the system's stdckdint.h. FreeBSD, for
14  * example, already has a Clang-compatible stdckdint.h header.
15  *
16  * The `stdckdint.h` header requires C 23 or newer.
17  */
18 #if __STDC_HOSTED__ && __has_include_next(<stdckdint.h>)
19 #include_next <stdckdint.h>
20 #else
21 
22 /* C23 7.20.1 Defines several macros for performing checked integer arithmetic*/
23 
24 #define __STDC_VERSION_STDCKDINT_H__ 202311L
25 
26 // Both A and B shall be any integer type other than "plain" char, bool, a bit-
27 // precise integer type, or an enumerated type, and they need not be the same.
28 
29 // R shall be a modifiable lvalue of any integer type other than "plain" char,
30 // bool, a bit-precise integer type, or an enumerated type. It shouldn't be
31 // short type, either. Otherwise, it may be unable to hold two the result of
32 // operating two 'int's.
33 
34 // A diagnostic message will be produced if A or B are not suitable integer
35 // types, or if R is not a modifiable lvalue of a suitable integer type or R
36 // is short type.
37 #define ckd_add(R, A, B) __builtin_add_overflow((A), (B), (R))
38 #define ckd_sub(R, A, B) __builtin_sub_overflow((A), (B), (R))
39 #define ckd_mul(R, A, B) __builtin_mul_overflow((A), (B), (R))
40 
41 #endif /* __STDC_HOSTED__ */
42 #endif /* __STDCKDINT_H */
43