std::ranges::borrowed_iterator_t, std::ranges::borrowed_subrange_t

 

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符号索引

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范围库

范围访问 begin cbegin   end cend rbegin crbegin   rend crend size ssize   data cdata empty

范围转换 std::from_range_t std::from_range (C++23)(C++23)     to (C++23)

悬垂迭代器处理 dangling borrowed_iterator_t borrowed_subrange_t

范围原语
range_size_trange_difference_trange_value_t elements_of (C++23)	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_reference_trange_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)

范围概念
range borrowed_range    sized_range	common_range view viewable_range	input_range output_range forward_range	bidirectional_range    random_access_range contiguous_range	constant_range (C++23)

视图
view_interface	subrange

范围工厂
empty_viewviews::empty	single_viewviews::single	basic_istream_viewviews::istream	iota_viewviews::iota	repeat_viewviews::repeat (C++23)(C++23)

范围适配器
views::all_tviews::all ref_view owning_view as_rvalue_viewviews::as_rvalue (C++23)(C++23)   filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while concat_viewviews::concat (C++26)(C++26)	drop_viewviews::drop drop_while_viewviews::drop_while join_viewviews::join join_with_viewviews::join_with (C++23)(C++23)   lazy_split_viewviews::lazy_split split_viewviews::split views::counted common_viewviews::common	reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)

范围生成器 std::generator (C++23)

范围适配器闭包对象 range_adaptor_closure (C++23)

范围适配器对象

辅助项
copyable-box movable-box (直到 C++23)  (C++23)	simple-view non-propagating-cache

 

定义在头文件 <ranges> 中
template< ranges::range R > using borrowed_iterator_t = /* 见下文 */;	(1)	(自 C++20 起)
template< ranges::range R > using borrowed_subrange_t = /* 见下文 */;	(2)	(自 C++20 起)

1) std::ranges::iterator_t<R> 如果 R 符合 borrowed_range，否则为 std::ranges::dangling。

2) std::ranges::subrange<std::ranges::iterator_t<R>> 如果 R 符合 borrowed_range，否则为 std::ranges::dangling。

这两个别名模板被一些 约束算法 用于避免返回可能悬垂的迭代器或视图。

可能的实现

borrowed_iterator_t
template< std::ranges::range R > using borrowed_iterator_t = std::conditional_t<std::ranges::borrowed_range<R>, std::ranges::iterator_t<R>, std::ranges::dangling>;
borrowed_subrange_t
template< std::ranges::range R > using borrowed_subrange_t = std::conditional_t<std::ranges::borrowed_range<R>, std::ranges::subrange<std::ranges::iterator_t<R>>, std::ranges::dangling>;

参见

ranges::dangling (C++20)

一个占位符类型，表示不应该返回迭代器或 subrange，因为它们将是悬垂的 (类)