contrib/llvm-project/libcxx/include/__ranges/dangling.h

   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>
  17
  18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  19 #pragma GCC system_header
  20 #endif
  21
  22 _LIBCPP_PUSH_MACROS
  23 #include <__undef_macros>
  24
  25 _LIBCPP_BEGIN_NAMESPACE_STD
  26
  27 #if !defined(_LIBCPP_HAS_NO_RANGES)
  28
  29 namespace ranges {
  30 struct dangling {
  31   dangling() = default;
  32   _LIBCPP_HIDE_FROM_ABI constexpr dangling(auto&&...) noexcept {}
  33 };
  34
  35 template <range _Rp>
  36 using borrowed_iterator_t = _If<borrowed_range<_Rp>, iterator_t<_Rp>, dangling>;
  37
  38 // borrowed_subrange_t defined in <__ranges/subrange.h>
  39 } // namespace ranges
  40
  41 #endif // !_LIBCPP_HAS_NO_RANGES
  42
  43 _LIBCPP_END_NAMESPACE_STD
  44
  45 _LIBCPP_POP_MACROS
  46
  47 #endif // _LIBCPP___RANGES_DANGLING_H