1 // -*- C++ -*-
2 //===----------------- __utility/to_underlying.h --------------------------===//
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_PUSH_MACROS
21 #include <__undef_macros>
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 #ifndef _LIBCPP_CXX03_LANG
26 template <class _Tp>
27 _LIBCPP_INLINE_VISIBILITY constexpr typename underlying_type<_Tp>::type
28 __to_underlying(_Tp __val) noexcept {
29   return static_cast<typename underlying_type<_Tp>::type>(__val);
30 }
31 #endif // !_LIBCPP_CXX03_LANG
32 
33 #if _LIBCPP_STD_VER > 20
34 template <class _Tp>
35 _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY constexpr underlying_type_t<_Tp>
36 to_underlying(_Tp __val) noexcept {
37   return _VSTD::__to_underlying(__val);
38 }
39 #endif
40 
41 _LIBCPP_END_NAMESPACE_STD
42 
43 _LIBCPP_POP_MACROS
44 
45 #endif // _LIBCPP___UTILITY_TO_UNDERLYING_H
46