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_ADD_RVALUE_REFERENCE_H
10 #define _LIBCPP___TYPE_TRAITS_ADD_RVALUE_REFERENCE_H
11 
12 #include <__config>
13 #include <__type_traits/is_referenceable.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 #if __has_builtin(__add_rvalue_reference)
22 
23 template <class _Tp>
24 using __add_rvalue_reference_t = __add_rvalue_reference(_Tp);
25 
26 #else
27 
28 template <class _Tp, bool = __libcpp_is_referenceable<_Tp>::value>
29 struct __add_rvalue_reference_impl {
30   typedef _LIBCPP_NODEBUG _Tp type;
31 };
32 template <class _Tp >
33 struct __add_rvalue_reference_impl<_Tp, true> {
34   typedef _LIBCPP_NODEBUG _Tp&& type;
35 };
36 
37 template <class _Tp>
38 using __add_rvalue_reference_t = typename __add_rvalue_reference_impl<_Tp>::type;
39 
40 #endif // __has_builtin(__add_rvalue_reference)
41 
42 template <class _Tp>
43 struct add_rvalue_reference {
44   using type = __add_rvalue_reference_t<_Tp>;
45 };
46 
47 #if _LIBCPP_STD_VER > 11
48 template <class _Tp>
49 using add_rvalue_reference_t = __add_rvalue_reference_t<_Tp>;
50 #endif
51 
52 _LIBCPP_END_NAMESPACE_STD
53 
54 #endif // _LIBCPP___TYPE_TRAITS_ADD_RVALUE_REFERENCE_H
55