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___RANGES_DANGLING_H 11 #define _LIBCPP___RANGES_DANGLING_H 12 13 #include <__config> 14 #include <__ranges/access.h> 15 #include <__ranges/concepts.h> 16 #include <__type_traits/conditional.h> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 # pragma GCC system_header 20 #endif 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 #if _LIBCPP_STD_VER > 17 25 26 namespace ranges { 27 struct dangling { 28 dangling() = default; 29 _LIBCPP_HIDE_FROM_ABI constexpr dangling(auto&&...) noexcept {} 30 }; 31 32 template <range _Rp> 33 using borrowed_iterator_t = _If<borrowed_range<_Rp>, iterator_t<_Rp>, dangling>; 34 35 // borrowed_subrange_t defined in <__ranges/subrange.h> 36 } // namespace ranges 37 38 #endif // _LIBCPP_STD_VER > 17 39 40 _LIBCPP_END_NAMESPACE_STD 41 42 #endif // _LIBCPP___RANGES_DANGLING_H 43