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_UNWRAP_REF_H 10#define _LIBCPP___TYPE_TRAITS_UNWRAP_REF_H 11 12#include <__config> 13#include <__type_traits/decay.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 21template <class _Tp> 22struct __unwrap_reference { 23 typedef _LIBCPP_NODEBUG _Tp type; 24}; 25 26template <class _Tp> 27class reference_wrapper; 28 29template <class _Tp> 30struct __unwrap_reference<reference_wrapper<_Tp> > { 31 typedef _LIBCPP_NODEBUG _Tp& type; 32}; 33 34template <class _Tp> 35struct decay; 36 37#if _LIBCPP_STD_VER >= 20 38template <class _Tp> 39struct unwrap_reference : __unwrap_reference<_Tp> {}; 40 41template <class _Tp> 42using unwrap_reference_t = typename unwrap_reference<_Tp>::type; 43 44template <class _Tp> 45struct unwrap_ref_decay : unwrap_reference<__decay_t<_Tp> > {}; 46 47template <class _Tp> 48using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type; 49#endif // _LIBCPP_STD_VER >= 20 50 51template <class _Tp> 52struct __unwrap_ref_decay 53#if _LIBCPP_STD_VER >= 20 54 : unwrap_ref_decay<_Tp> 55#else 56 : __unwrap_reference<__decay_t<_Tp> > 57#endif 58{ 59}; 60 61_LIBCPP_END_NAMESPACE_STD 62 63#endif // _LIBCPP___TYPE_TRAITS_UNWRAP_REF_H 64