xref: /freebsd/contrib/llvm-project/libcxx/include/__utility/to_underlying.h (revision 5956d97f4b3204318ceb6aa9c77bd0bc6ea87a41)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___UTILITY_TO_UNDERLYING_H
11 #define _LIBCPP___UTILITY_TO_UNDERLYING_H
12 
13 #include <__config>
14 #include <type_traits>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #pragma GCC system_header
18 #endif
19 
20 _LIBCPP_BEGIN_NAMESPACE_STD
21 
22 #ifndef _LIBCPP_CXX03_LANG
23 template <class _Tp>
24 _LIBCPP_INLINE_VISIBILITY constexpr typename underlying_type<_Tp>::type
25 __to_underlying(_Tp __val) noexcept {
26   return static_cast<typename underlying_type<_Tp>::type>(__val);
27 }
28 #endif // !_LIBCPP_CXX03_LANG
29 
30 #if _LIBCPP_STD_VER > 20
31 template <class _Tp>
32 _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY constexpr underlying_type_t<_Tp>
33 to_underlying(_Tp __val) noexcept {
34   return _VSTD::__to_underlying(__val);
35 }
36 #endif
37 
38 _LIBCPP_END_NAMESPACE_STD
39 
40 #endif // _LIBCPP___UTILITY_TO_UNDERLYING_H
41