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_IS_REFERENCEABLE_H
10 #define _LIBCPP___TYPE_TRAITS_IS_REFERENCEABLE_H
11 
12 #include <__config>
13 #include <__type_traits/integral_constant.h>
14 #include <__type_traits/is_same.h>
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 #if __has_builtin(__is_referenceable)
23 template <class _Tp>
24 struct __libcpp_is_referenceable : integral_constant<bool, __is_referenceable(_Tp)> {};
25 #else
26 struct __libcpp_is_referenceable_impl {
27   template <class _Tp>
28   static _Tp& __test(int);
29   template <class _Tp>
30   static false_type __test(...);
31 };
32 
33 template <class _Tp>
34 struct __libcpp_is_referenceable
35     : integral_constant<bool, _IsNotSame<decltype(__libcpp_is_referenceable_impl::__test<_Tp>(0)), false_type>::value> {
36 };
37 #endif // __has_builtin(__is_referenceable)
38 
39 _LIBCPP_END_NAMESPACE_STD
40 
41 #endif // _LIBCPP___TYPE_TRAITS_IS_REFERENCEABLE_H
42