1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___UTILITY_FORWARD_H
11 #define _LIBCPP___UTILITY_FORWARD_H
12 
13 #include <__config>
14 #include <__type_traits/is_reference.h>
15 #include <__type_traits/remove_reference.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_BEGIN_NAMESPACE_STD
22 
23 template <class _Tp>
24 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
25 forward(_LIBCPP_LIFETIMEBOUND __libcpp_remove_reference_t<_Tp>& __t) _NOEXCEPT {
26   return static_cast<_Tp&&>(__t);
27 }
28 
29 template <class _Tp>
30 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
31 forward(_LIBCPP_LIFETIMEBOUND __libcpp_remove_reference_t<_Tp>&& __t) _NOEXCEPT {
32   static_assert(!is_lvalue_reference<_Tp>::value, "cannot forward an rvalue as an lvalue");
33   return static_cast<_Tp&&>(__t);
34 }
35 
36 _LIBCPP_END_NAMESPACE_STD
37 
38 #endif // _LIBCPP___UTILITY_FORWARD_H
39