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_LVALUE_REFERENCE_H 10#define _LIBCPP___TYPE_TRAITS_ADD_LVALUE_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_lvalue_reference) 22 23template <class _Tp> 24using __add_lvalue_reference_t = __add_lvalue_reference(_Tp); 25 26#else 27 28template <class _Tp, bool = __libcpp_is_referenceable<_Tp>::value> 29struct __add_lvalue_reference_impl { 30 typedef _LIBCPP_NODEBUG _Tp type; 31}; 32template <class _Tp > 33struct __add_lvalue_reference_impl<_Tp, true> { 34 typedef _LIBCPP_NODEBUG _Tp& type; 35}; 36 37template <class _Tp> 38using __add_lvalue_reference_t = typename __add_lvalue_reference_impl<_Tp>::type; 39 40#endif // __has_builtin(__add_lvalue_reference) 41 42template <class _Tp> 43struct add_lvalue_reference { 44 using type _LIBCPP_NODEBUG = __add_lvalue_reference_t<_Tp>; 45}; 46 47#if _LIBCPP_STD_VER > 11 48template <class _Tp> using add_lvalue_reference_t = __add_lvalue_reference_t<_Tp>; 49#endif 50 51_LIBCPP_END_NAMESPACE_STD 52 53#endif // _LIBCPP___TYPE_TRAITS_ADD_LVALUE_REFERENCE_H 54