1 //===----------------------------------------------------------------------===// 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 #ifndef _LIBCPP___TYPE_TRAITS_UNDERLYING_TYPE_H 10 #define _LIBCPP___TYPE_TRAITS_UNDERLYING_TYPE_H 11 12 #include <__config> 13 #include <__type_traits/is_enum.h> 14 15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 16 # pragma GCC system_header 17 #endif 18 19 _LIBCPP_BEGIN_NAMESPACE_STD 20 21 template <class _Tp, bool = is_enum<_Tp>::value> 22 struct __underlying_type_impl; 23 24 template <class _Tp> 25 struct __underlying_type_impl<_Tp, false> {}; 26 27 template <class _Tp> 28 struct __underlying_type_impl<_Tp, true> { 29 typedef __underlying_type(_Tp) type; 30 }; 31 32 template <class _Tp> 33 struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {}; 34 35 #if _LIBCPP_STD_VER >= 14 36 template <class _Tp> 37 using underlying_type_t = typename underlying_type<_Tp>::type; 38 #endif 39 40 _LIBCPP_END_NAMESPACE_STD 41 42 #endif // _LIBCPP___TYPE_TRAITS_UNDERLYING_TYPE_H 43