实验库头文件 <experimental/ranges/iterator>

 

C++

编译器支持

独立和托管

语言

标准库

标准库头文件

命名要求

功能测试宏 (C++20)

语言支持库

概念库 (C++20)

元编程库 (C++11)

诊断库

通用实用程序库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

并发支持库 (C++11)

执行支持库 (C++26)

技术规范

符号索引

外部库

 

标准库头文件

语言支持
<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <stdfloat> (C++23) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11) <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
概念
<concepts> (C++20)
诊断
<stdexcept> <stacktrace> (C++23)	<cassert>	<cerrno>	<system_error> (C++11)
内存管理
<memory>	<memory_resource> (C++17)	<scoped_allocator> (C++11)
元编程
<type_traits> (C++11)	<ratio> (C++11)
通用实用程序
<utility> <tuple> (C++11) <optional> (C++17) <variant> (C++17)	<any> (C++17) <debugging> (C++26) <expected> (C++23) <bitset>	<functional> <typeindex> (C++11) <execution> (C++17)	<charconv> (C++17) <format> (C++20) <bit> (C++20)
字符串
<string_view> (C++17) <string>	<cctype> <cwctype>	<cstring> <cwchar>	<cuchar> (C++11)
容器
<array> (C++11) <deque> <forward_list> (C++11) <list>	<vector> <map> <set> <unordered_map> (C++11)	<unordered_set> (C++11) <queue> <stack> <flat_map> (C++23)	<flat_set> (C++23) <span> (C++20) <mdspan> (C++23) <inplace_vector> (C++26)
迭代器
<iterator>
范围
<ranges> (C++20)	<generator> (C++23)
算法
<algorithm>	<numeric>
数值
<cfenv> (C++11) <complex>	<random> (C++11) <valarray>	<cmath> <linalg> (C++26)	<numbers> (C++20)
时间
<chrono> (C++11)	<ctime>
本地化
<locale>	<clocale>	<codecvt> (C++11/17/26*)	<text_encoding> (C++26)
输入/输出
<iosfwd> <iostream> <ios> <streambuf>	<istream> <ostream> <iomanip> <print> (C++23)	<sstream> <spanstream> (C++23) <fstream> <syncstream> (C++20)	<filesystem> (C++17) <cstdio> <cinttypes> (C++11) <strstream> (C++98/26*)
正则表达式
<regex> (C++11)
并发支持
<stop_token> (C++20) <thread> (C++11) <atomic> (C++11) <rcu> (C++26)	<stdatomic.h> (C++23) <mutex> (C++11) <shared_mutex> (C++14)	<condition_variable> (C++11)   <semaphore> (C++20) <latch> (C++20)	<barrier> (C++20) <future> (C++11) <hazard_pointer> (C++26)
C 兼容性
<cstdbool> (C++11/17/20*)   <ccomplex> (C++11/17/20*)	<ctgmath> (C++11/17/20*)	<cstdalign> (C++11/17/20*)	<ciso646> (直到 C++20)

 

实验库头文件

执行 P2300
<experimental/execution>
文件系统 TS
<experimental/filesystem>
并行 TS (v1, v2)
experimental/algorithm experimental/execution_policy experimental/exception_list	experimental/numeric <experimental/simd> experimental/task_block
库基础 TS (v1, v2, v3)
experimental/algorithm <experimental/any> experimental/array experimental/chrono experimental/deque experimental/forward_list <experimental/functional> experimental/future experimental/iterator experimental/list experimental/map experimental/memory <experimental/memory_resource> experimental/numeric <experimental/optional> experimental/propagate_const	experimental/random experimental/ratio experimental/regex experimental/scope experimental/set experimental/source_location experimental/string <experimental/string_view> experimental/system_error experimental/tuple experimental/type_traits experimental/unordered_map experimental/unordered_set experimental/utility experimental/vector
并发 TS
experimental/atomic experimental/barrier	experimental/future experimental/latch
范围 TS
<experimental/ranges/algorithm> <experimental/ranges/concepts> <experimental/ranges/functional>         <experimental/ranges/iterator>	<experimental/ranges/random> <experimental/ranges/tuple> <experimental/ranges/type_traits> <experimental/ranges/utility>
协程 TS
experimental/coroutine
网络 TS
experimental/buffer experimental/executor experimental/internet experimental/io_context	<experimental/net> experimental/netfwd experimental/socket experimental/timer
反射 TS
<experimental/reflect>

 

该头文件是 范围 库的一部分。

与迭代器相关的概念

在命名空间 std::experimental::ranges 中定义

迭代器概念

可读	指定类型可以通过应用运算符 * 来读取。 (概念)
可写	指定可以将值写入迭代器引用的对象。 (概念)
弱可增量	指定一个 Semiregular 类型可以使用前增量和后增量运算符进行增量。 (概念)
可增量	指定一个 WeaklyIncrementable 类型的增量操作是等式保持的，并且该类型是 EqualityComparable。 (概念)
迭代器	指定一个类型对象可以被增量和解引用。 (概念)
哨兵	指定一个类型的对象是 Iterator 类型的哨兵。 (概念)
大小哨兵	指定 - 运算符可以应用于迭代器和哨兵，以计算它们在恒定时间内的差异。 (概念)
输入迭代器	指定一个类型是输入迭代器，即它的引用值可以被读取，并且它可以被前增量和后增量。 (概念)
输出迭代器	指定一个类型是给定值类型的输出迭代器，即该类型的值可以被写入，并且它可以被前增量和后增量。 (概念)
前向迭代器	指定一个 InputIterator 是一个前向迭代器，支持相等比较和多遍。 (概念)
双向迭代器	指定一个 ForwardIterator 是一个双向迭代器，支持向后移动。 (概念)
随机访问迭代器	指定一个 BidirectionalIterator 是一个随机访问迭代器，支持在恒定时间内前进和下标。 (概念)

间接可调用概念

IndirectUnaryInvocableIndirectRegularUnaryInvocable	指定一个可调用类型可以使用 Readable 类型解引用的结果进行调用。 (概念)
间接一元谓词	指定一个可调用对象，当它使用 Readable 类型解引用的结果进行调用时，满足 Predicate。 (概念)
间接关系	指定一个可调用对象，当它使用一些 Readable 类型解引用的结果进行调用时，满足 Relation。 (概念)
间接严格弱序	指定一个可调用对象，当它使用一些 Readable 类型解引用的结果进行调用时，满足 StrictWeakOrder。 (概念)

通用算法需求

间接可移动	指定可以从 Readable 类型移动到 Writable 类型的值。 (概念)
间接可移动可存储	指定可以从 Readable 类型移动到 Writable 类型的值，并且可以通过中间对象执行移动。 (概念)
间接可复制	指定可以从 Readable 类型复制到 Writable 类型的值。 (概念)
间接可复制可存储	指定可以从 Readable 类型复制到 Writable 类型的值，并且可以通过中间对象执行复制。 (概念)
间接可交换	指定两个 Readable 类型引用的值可以被交换。 (概念)
间接可比较	指定两个 Readable 类型引用的值可以被比较。 (概念)
可置换	指定就地重新排列元素的算法的通用要求 (概念)
可合并	指定通过复制元素将排序后的序列合并到输出序列中的算法的要求 (概念)
可排序	指定将序列排列成排序序列的算法的通用要求 (概念)

概念实用程序

indirect_result_of	计算在对一些Readable类型进行解引用之后的结果上调用可调用对象的结果 (类模板)
projected	用于指定接受投影的算法的约束的辅助模板 (类模板)

迭代器原语

迭代器实用程序

在命名空间 std::experimental::ranges 中定义
iter_move	将对象的解引用结果转换为其关联的右值引用类型 (定制点对象)
iter_swap	交换两个可解引用的对象引用的值 (定制点对象)

迭代器特征

在命名空间 std::experimental::ranges 中定义
difference_type	获取WeaklyIncrementable类型的差值类型 (类模板)
value_type	获取Readable类型的值类型 (类模板)
iterator_category	获取输入迭代器类型的迭代器类别 (类模板)
iterator_traits	收集迭代器关联类型的兼容性特征类 (别名模板)
reference_trvalue_reference_titer_common_reference_t	获取可解引用对象的关联引用类型 (别名模板)

迭代器类别标签

在命名空间 std::experimental::ranges 中定义
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag	用于指示迭代器类别的空类类型 (类)

std::iterator_traits 特化

在命名空间 std 中定义
std::iterator_traits<InputIterator>std::iterator_traits<OutputIterator>	为范围 TS 迭代器特化 std::iterator_traits (类模板特化)

迭代器操作

在命名空间 std::experimental::ranges 中定义
advance	将迭代器向前移动给定的距离 (函数模板)
distance	返回迭代器和哨兵之间的距离，或者返回范围的开始和结束之间的距离 (函数模板)
next	递增迭代器 (函数模板)
prev	递减迭代器 (函数模板)

迭代器适配器

在命名空间 std::experimental::ranges 中定义
reverse_iterator	用于反向遍历的迭代器适配器 (类模板)
back_insert_iterator	用于在容器末尾插入的迭代器适配器 (类模板)
front_insert_iterator	用于在容器开头插入的迭代器适配器 (类模板)
insert_iterator	用于将元素插入容器的迭代器适配器 (类模板)
move_iterator	解引用到右值引用的迭代器适配器 (类模板)
move_sentinel	与 move_iterator 一起使用的哨兵适配器 (类模板)
common_iterator	将迭代器-哨兵对适配到一个通用迭代器类型，以便与传统算法一起使用 (类模板)
counted_iterator	跟踪其距起始位置的距离的迭代器适配器 (类模板)
default_sentinel	空哨兵类型，用于与知道其范围边界的迭代器类型一起使用 (类)
dangling	可能悬空迭代器的包装器 (类模板)
safe_iterator_t	将右值范围的迭代器类型用 dangling 包装的别名模板 (别名模板)
unreachable	与任何迭代器一起使用的哨兵类型，用于表示无限范围 (类)

流迭代器

在命名空间 std::experimental::ranges 中定义
istream_iterator	从 std::basic_istream 读取的输入迭代器 (类模板)
ostream_iterator	写入 std::basic_ostream 的输出迭代器 (类模板)
istreambuf_iterator	从 std::basic_streambuf 读取的输入迭代器 (类模板)
ostreambuf_iterator	写入 std::basic_streambuf 的输出迭代器 (类模板)

概要

namespace std { namespace experimental { namespace ranges { inline namespace v1 {
 
template <class T> concept bool /* dereferenceable */ // exposition only
  = requires(T& t) { {*t} -> auto&&; };
 
namespace {
  constexpr /* unspecified */ iter_move = /* unspecified */;
  constexpr /* unspecified */ iter_swap = /* unspecified */;
}
 
template <class> struct difference_type;
template <class T> using difference_type_t
  = typename difference_type<T>::type;
 
template <class> struct value_type;
template <class T> using value_type_t
  = typename value_type<T>::type;
 
template <class> struct iterator_category;
template <class T> using iterator_category_t
  = typename iterator_category<T>::type;
 
template </* dereferenceable */ T> using reference_t
  = decltype(*declval<T&>());
 
template </* dereferenceable */ T>
    requires /* see definition */ using rvalue_reference_t
  = decltype(ranges::iter_move(declval<T&>()));
 
template <class In>
concept bool Readable = /* see definition */;
 
template <class Out, class T>
concept bool Writable = /* see definition */;
 
template <class I>
concept bool WeaklyIncrementable = /* see definition */;
 
template <class I>
concept bool Incrementable = /* see definition */;
 
template <class I>
concept bool Iterator = /* see definition */;
 
template <class S, class I>
concept bool Sentinel = /* see definition */;
 
template <class S, class I>
  constexpr bool disable_sized_sentinel = false;
 
template <class S, class I>
concept bool SizedSentinel = /* see definition */;
 
template <class I>
concept bool InputIterator = /* see definition */;
 
template <class I>
concept bool OutputIterator = /* see definition */;
 
template <class I>
concept bool ForwardIterator = /* see definition */;
 
template <class I>
concept bool BidirectionalIterator = /* see definition */;
 
template <class I>
concept bool RandomAccessIterator = /* see definition */;
 
template <class F, class I>
concept bool IndirectUnaryInvocable = /* see definition */;
 
template <class F, class I>
concept bool IndirectRegularUnaryInvocable = /* see definition */;
 
template <class F, class I>
concept bool IndirectUnaryPredicate = /* see definition */;
 
template <class F, class I1, class I2 = I1>
concept bool IndirectRelation = /* see definition */;
 
template <class F, class I1, class I2 = I1>
concept bool IndirectStrictWeakOrder = /* see definition */;
 
template <class> struct indirect_result_of;
 
template <class F, class... Is>
  requires Invocable<F, reference_t<Is>...>
struct indirect_result_of<F(Is...)>;
 
template <class F>
using indirect_result_of_t
  = typename indirect_result_of<F>::type;
 
template <Readable I, IndirectRegularUnaryInvocable<I> Proj>
struct projected;
 
template <WeaklyIncrementable I, class Proj>
struct difference_type<projected<I, Proj>>;
 
template <class In, class Out>
concept bool IndirectlyMovable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyMovableStorable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyCopyable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyCopyableStorable = /* see definition */;
 
template <class I1, class I2 = I1>
concept bool IndirectlySwappable = /* see definition */;
 
template <class I1, class I2, class R = equal_to<>, class P1 = identity,
    class P2 = identity>
concept bool IndirectlyComparable = /* see definition */;
 
template <class I>
concept bool Permutable = /* see definition */;
 
template <class I1, class I2, class Out,
    class R = less<>, class P1 = identity, class P2 = identity>
concept bool Mergeable = /* see definition */;
 
template <class I, class R = less<>, class P = identity>
concept bool Sortable = /* see definition */;
 
template <class Iterator> using iterator_traits = /* see definition */;
 
template <Readable T> using iter_common_reference_t
  = common_reference_t<reference_t<T>, value_type_t<T>&>;
 
struct output_iterator_tag { };
struct input_iterator_tag { };
struct forward_iterator_tag : input_iterator_tag { };
struct bidirectional_iterator_tag : forward_iterator_tag { };
struct random_access_iterator_tag : bidirectional_iterator_tag { };
 
namespace {
  constexpr /* unspecified */ advance = /* unspecified */;
  constexpr /* unspecified */ distance = /* unspecified */;
  constexpr /* unspecified */ next = /* unspecified */;
  constexpr /* unspecified */ prev = /* unspecified */;
}
 
template <BidirectionalIterator I> class reverse_iterator;
 
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator==(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator!=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
 
template <class I1, class I2>
    requires SizedSentinel<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <RandomAccessIterator I>
  constexpr reverse_iterator<I> operator+(
    difference_type_t<I> n,
    const reverse_iterator<I>& x);
 
template <BidirectionalIterator I>
constexpr reverse_iterator<I> make_reverse_iterator(I i);
 
template <class Container> class back_insert_iterator;
template <class Container>
  back_insert_iterator<Container> back_inserter(Container& x);
 
template <class Container> class front_insert_iterator;
template <class Container>
  front_insert_iterator<Container> front_inserter(Container& x);
 
template <class Container> class insert_iterator;
template <class Container>
  insert_iterator<Container> inserter(Container& x, iterator_t<Container> i);
 
template <InputIterator I> class move_iterator;
 
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator==(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator!=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
 
template <class I1, class I2>
    requires SizedSentinel<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const move_iterator<I1>& x,
    const move_iterator<I2>& y);
template <RandomAccessIterator I>
  constexpr move_iterator<I> operator+(
    difference_type_t<I> n,
    const move_iterator<I>& x);
 
template <InputIterator I>
  constexpr move_iterator<I> make_move_iterator(I i);
 
template <Semiregular S> class move_sentinel;
 
template <class I, Sentinel<I> S>
  constexpr bool operator==(
    const move_iterator<I>& i, const move_sentinel<S>& s);
template <class I, Sentinel<I> S>
  constexpr bool operator==(
    const move_sentinel<S>& s, const move_iterator<I>& i);
template <class I, Sentinel<I> S>
  constexpr bool operator!=(
    const move_iterator<I>& i, const move_sentinel<S>& s);
template <class I, Sentinel<I> S>
  constexpr bool operator!=(
    const move_sentinel<S>& s, const move_iterator<I>& i);
 
template <class I, SizedSentinel<I> S>
  constexpr difference_type_t<I> operator-(
    const move_sentinel<S>& s, const move_iterator<I>& i);
template <class I, SizedSentinel<I> S>
  constexpr difference_type_t<I> operator-(
    const move_iterator<I>& i, const move_sentinel<S>& s);
 
template <Semiregular S>
  constexpr move_sentinel<S> make_move_sentinel(S s);
 
template <Iterator I, Sentinel<I> S>
  requires !Same<I, S>
class common_iterator;
 
template <Readable I, class S>
struct value_type<common_iterator<I, S>>;
 
template <InputIterator I, class S>
struct iterator_category<common_iterator<I, S>>;
 
template <ForwardIterator I, class S>
struct iterator_category<common_iterator<I, S>>;
 
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
bool operator==(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
  requires EqualityComparableWith<I1, I2>
bool operator==(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
bool operator!=(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
 
template <class I2, SizedSentinel<I2> I1, SizedSentinel<I2> S1, SizedSentinel<I1> S2>
difference_type_t<I2> operator-(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
 
class default_sentinel;
 
template <Iterator I> class counted_iterator;
 
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator==(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
constexpr bool operator==(
  const counted_iterator<auto>& x, default_sentinel);
constexpr bool operator==(
  default_sentinel, const counted_iterator<auto>& x);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator!=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
constexpr bool operator!=(
  const counted_iterator<auto>& x, default_sentinel y);
constexpr bool operator!=(
  default_sentinel x, const counted_iterator<auto>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator<(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator<=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator>(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator>=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
 
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I>
  constexpr difference_type_t<I> operator-(
    const counted_iterator<I>& x, default_sentinel y);
template <class I>
  constexpr difference_type_t<I> operator-(
    default_sentinel x, const counted_iterator<I>& y);
template <RandomAccessIterator I>
  constexpr counted_iterator<I>
    operator+(difference_type_t<I> n, const counted_iterator<I>& x);
 
template <Iterator I>
  constexpr counted_iterator<I> make_counted_iterator(I i, difference_type_t<I> n);
 
class unreachable;
template <Iterator I>
  constexpr bool operator==(const I&, unreachable) noexcept;
template <Iterator I>
  constexpr bool operator==(unreachable, const I&) noexcept;
template <Iterator I>
  constexpr bool operator!=(const I&, unreachable) noexcept;
template <Iterator I>
  constexpr bool operator!=(unreachable, const I&) noexcept;
 
template <class T> class dangling;
 
template <class T, class CharT = char, class Traits = char_traits<CharT>,
    class Distance = ptrdiff_t>
  class istream_iterator;
 
template <class T, class CharT, class Traits, class Distance>
  bool operator==(const istream_iterator<T, CharT, Traits, Distance>& x,
    const istream_iterator<T, CharT, Traits, Distance>& y);
template <class T, class CharT, class Traits, class Distance>
  bool operator==(default_sentinel x,
    const istream_iterator<T, CharT, Traits, Distance>& y);
template <class T, class CharT, class Traits, class Distance>
  bool operator==(const istream_iterator<T, CharT, Traits, Distance>& x,
    default_sentinel y);
template <class T, class CharT, class Traits, class Distance>
  bool operator!=(const istream_iterator<T, CharT, Traits, Distance>& x,
    const istream_iterator<T, CharT, Traits, Distance>& y);
template <class T, class CharT, class Traits, class Distance>
  bool operator!=(default_sentinel x,
    const istream_iterator<T, CharT, Traits, Distance>& y);
template <class T, class CharT, class Traits, class Distance>
  bool operator!=(const istream_iterator<T, CharT, Traits, Distance>& x,
    default_sentinel y);
 
template <class T, class CharT = char, class Traits = char_traits<CharT>>
  class ostream_iterator;
 
template <class CharT, class Traits = char_traits<CharT> >
  class istreambuf_iterator;
 
template <class CharT, class Traits>
  bool operator==(const istreambuf_iterator<CharT, Traits>& a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator==(default_sentinel a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator==(const istreambuf_iterator<CharT, Traits>& a,
    default_sentinel b);
template <class CharT, class Traits>
  bool operator!=(const istreambuf_iterator<CharT, Traits>& a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator!=(default_sentinel a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator!=(const istreambuf_iterator<CharT, Traits>& a,
    default_sentinel b);
 
template <class CharT, class Traits = char_traits<CharT> >
  class ostreambuf_iterator;
 
}}}}
 
namespace std {
  template <experimental::ranges::Iterator Out>
    struct iterator_traits<Out>;
  template <experimental::ranges::InputIterator In>
    struct iterator_traits<In>;
  template <experimental::ranges::InputIterator In>
      requires experimental::ranges::Sentinel<In, In>
    struct iterator_traits;
}