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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H11#define _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H12 13#include <__config>14#include <__iterator/concepts.h>15 16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)17# pragma GCC system_header18#endif19 20_LIBCPP_BEGIN_NAMESPACE_STD21 22#if _LIBCPP_STD_VER >= 2023 24struct unreachable_sentinel_t {25 template <weakly_incrementable _Iter>26 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(unreachable_sentinel_t, const _Iter&) noexcept {27 return false;28 }29};30 31inline constexpr unreachable_sentinel_t unreachable_sentinel{};32 33#endif // _LIBCPP_STD_VER >= 2034 35_LIBCPP_END_NAMESPACE_STD36 37#endif // _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H38