| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___TYPE_TRAITS_IS_EMPTY_H |
| #define _LIBCPP___TYPE_TRAITS_IS_EMPTY_H |
| |
| #include <__config> |
| #include <__type_traits/integral_constant.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC) |
| |
| template <class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS is_empty |
| : public integral_constant<bool, __is_empty(_Tp)> {}; |
| |
| #else // __has_feature(is_empty) |
| |
| template <class _Tp> |
| struct __is_empty1 |
| : public _Tp |
| { |
| double __lx; |
| }; |
| |
| struct __is_empty2 |
| { |
| double __lx; |
| }; |
| |
| template <class _Tp, bool = is_class<_Tp>::value> |
| struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {}; |
| |
| template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {}; |
| |
| template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {}; |
| |
| #endif // __has_feature(is_empty) |
| |
| #if _LIBCPP_STD_VER > 14 |
| template <class _Tp> |
| inline constexpr bool is_empty_v = is_empty<_Tp>::value; |
| #endif |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___TYPE_TRAITS_IS_EMPTY_H |