xref: /freebsd/contrib/llvm-project/libcxx/include/__utility/forward.h (revision 4f5890a0fb086324a657f3cd7ba1abc57274e0db)
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>
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 template <class _Tp>
23 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _Tp&&
24 forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT {
25   return static_cast<_Tp&&>(__t);
26 }
27 
28 template <class _Tp>
29 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _Tp&&
30 forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT {
31   static_assert(!is_lvalue_reference<_Tp>::value, "cannot forward an rvalue as an lvalue");
32   return static_cast<_Tp&&>(__t);
33 }
34 
35 _LIBCPP_END_NAMESPACE_STD
36 
37 #endif // _LIBCPP___UTILITY_FORWARD_H
38