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 21template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl; 22 23template <class _Tp> 24struct __underlying_type_impl<_Tp, false> {}; 25 26template <class _Tp> 27struct __underlying_type_impl<_Tp, true> 28{ 29 typedef __underlying_type(_Tp) type; 30}; 31 32template <class _Tp> 33struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {}; 34 35#if _LIBCPP_STD_VER > 11 36template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type; 37#endif 38 39_LIBCPP_END_NAMESPACE_STD 40 41#endif // _LIBCPP___TYPE_TRAITS_UNDERLYING_TYPE_H 42