std::ranges::views::to_input,std::ranges::to_input_view

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Ranges library

Range access

begin
cbegin
end
cend

rbegin
crbegin
rend
crend

size
ssize
data
cdata

reserve_hint (C++26)
empty

Range conversions
std::from_range_t std::from_range (C++23)(C++23)
to (C++23)

Dangling iterator handling
dangling
borrowed_iterator_t
borrowed_subrange_t

Range primitives

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)

Range concepts

range
borrowed_range
common_range

sized_range
viewable_range
view

input_range
output_range
forward_range

bidirectional_range
random_access_range
contiguous_range

approximately_sized_range (C++26)
constant_range (C++23)

empty_viewviews::empty

single_viewviews::single

basic_istream_viewviews::istream

iota_viewviews::iota

repeat_viewviews::repeat

(C++23)(C++23)

Range adaptors

views::all_tviews::all
as_rvalue_viewviews::as_rvalue (C++23)(C++23)
filter_viewviews::filter
transform_viewviews::transform
take_viewviews::take
take_while_viewviews::take_while
common_viewviews::common
views::counted
to_input_viewviews::to_input (C++26)(C++26)

ref_view
drop_viewviews::drop
drop_while_viewviews::drop_while
lazy_split_viewviews::lazy_split
split_viewviews::split
join_viewviews::join
join_with_viewviews::join_with (C++23)(C++23)
concat_viewviews::concat (C++26)(C++26)
cache_latest_viewviews::cache_latest (C++26)(C++26)

owning_view
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)

Range generators
std::generator (C++23)

Range adaptor closure objects
range_adaptor_closure (C++23)

Range adaptor objects

Helper items

copyable-box
movable-box

(until C++23) (C++23)

simple-view
non-propagating-cache

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std::ranges::to_input_view

Member functions
to_input_view::to_input_view
to_input_view::base
to_input_view::begin
to_input_view::end
to_input_view::size
Deduction guides
Iterator
Member functions
to_input_view::iterator::iterator
to_input_view::iterator::base
to_input_view::iterator::operator*
to_input_view::iterator::operator++ to_input_view::iterator::operator++(int)
Non-member functions
operator==(to_input_view::iterator)
operator-(to_input_view::iterator)
iter_move(to_input_view::iterator)
iter_swap(to_input_view::iterator)

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Defined in header`<ranges>`
template<ranges::input_range V> requiresranges::view<V> class to_input_view :publicranges::view_interface<to_input_view<V>>	(1)	(since C++26)
namespace views{ inlineconstexpr/* unspecified / to_input=/ unspecified */; }	(2)	(since C++26)
Call signature
template<ranges::viewable_range R> requires/* see below */ constexprranges::viewauto to_input( R&& r);		(since C++26)

1) A range adaptor that represents a view of an underlyingview as aninput_range-only and not acommon_range.

2)RangeAdaptorObject. Lete be a subexpression, and letT bedecltype(e). Then the expressionviews::to_input(e) isexpression-equivalent to:

views::all(e), if it is a well-formed expression and all of the conditions below aretrue:
- T modelsinput_range,
- T does not satisfycommon_range, and
- T does not satisfyforward_range.
to_input_view{e} otherwise.

Consequently,to_input_view never models range concepts that are stronger thaninput_range. In particular, it does not model all of these:

Additionally,to_input_view does not modelcommon_range. However, it does modelborrowed_range,constant_range, andsized_range when the underlying viewV models respective concepts.

[edit]Data members

Member	Description
`Vbase_`(private)	the underlying view (exposition-only member object*)

[edit]Member functions

(constructor)	constructs a`to_input_view` (public member function)
base	returns a copy of the underlying (adapted) view (public member function)
begin	returns an iterator to the beginning (public member function)
end	returns an iterator or a sentinel to the end (public member function)
size	returns the number of elements. Provided only if the underlying (adapted) range satisfies`sized_range`. (public member function)
Inherited fromstd::ranges::view_interface
empty	returns whether the derived view is empty, provided only if it satisfies`sized_range` or`forward_range` (public member function of`std::ranges::view_interface<D>`)[edit]
cbegin (C++23)	returns a constant iterator to the beginning of the range (public member function of`std::ranges::view_interface<D>`)[edit]
cend (C++23)	returns a sentinel for the constant iterator of the range (public member function of`std::ranges::view_interface<D>`)[edit]
operator bool	returns whether the derived view is not empty, provided only ifranges::empty is applicable to it (public member function of`std::ranges::view_interface<D>`)[edit]
data	gets the address of derived view's data, provided only if its iterator type satisfies`contiguous_iterator` (public member function of`std::ranges::view_interface<D>`)[edit]
front	returns the first element in the derived view, provided if it satisfies`forward_range` (public member function of`std::ranges::view_interface<D>`)[edit]
back	returns the last element in the derived view, provided only if it satisfies`bidirectional_range` and`common_range` (public member function of`std::ranges::view_interface<D>`)[edit]
operator[]	returns the`n`^th element in the derived view, provided only if it satisfies`random_access_range` (public member function of`std::ranges::view_interface<D>`)[edit]

std::ranges::to_input_view::to_input_view

to_input_view() requiresstd::default_initializable<V>=default;	(1)	(since C++26)
constexprexplicit to_input_view( V base);	(2)	(since C++26)

1) Value-initializesbase_ via its default member initializer (= V()).

2) Initializesbase_ withstd::move(base).

Parameters

base

a view

std::ranges::to_input_view::base

constexpr V base()const& requiresstd::copy_constructible<V>;	(1)	(since C++26)
constexpr V base()&&;	(2)	(since C++26)

1) Copy-constructs the result from the underlying view. Equivalent toreturn base_;.

2) Move-constructs the result from the underlying view. Equivalent toreturn std::move(base_);.

std::ranges::to_input_view::begin

constexprauto begin() requires(!__simple_view<V>);	(1)	(since C++26)
constexprauto begin()const requiresranges::range<const V>;	(2)	(since C++26)

1) Equivalent toreturn/*iterator*/<false>(ranges::begin(base_));

2) Equivalent toreturn/*iterator*/<true>(ranges::begin(base_));

std::ranges::to_input_view::end

constexprauto end() requires(!__simple_view<V>);	(1)	(since C++26)
constexprauto end()const requiresranges::range<const V>;	(2)	(since C++26)

1,2) Equivalent toreturnranges::end(base_);

std::ranges::to_input_view::size

constexprauto size() requiresranges::sized_range<V>;	(1)	(since C++26)
constexprauto size()const requiresranges::sized_range<const V>;	(2)	(since C++26)

1,2) Equivalent toreturnranges::size(base_);

[edit]Deduction guides

template<class R> to_input_view( R&&)-> to_input_view<views::all_t<R>>;		(since C++26)

[edit]Nested classes

iterator

the iterator type
(exposition-only member class template*)

[edit]Helper templates

template<class T> constexprbool enable_borrowed_range<std::ranges::to_input_view<T>>= ranges::enable_borrowed_range<T>;		(since C++26)

This specialization ofstd::ranges::enable_borrowed_range makesto_input_view satisfyborrowed_range when the underlying view satisfies it.

[edit]Notes

to_input_view can be useful to avoid the overhead necessary to provide support for the operations needed for greater iterator strength.

Feature-test macro	Value	Std	Feature
`__cpp_lib_ranges_to_input`	`202502L`	(C++26)	`std::ranges::to_input_view`

[edit]Example

This section is incomplete
Reason: no example

[edit]See also

ranges::input_range (C++20)	specifies a range whose iterator type satisfies`input_iterator` (concept)[edit]
ranges::common_viewviews::common (C++20)	converts a`view` into a`common_range` (class template)(range adaptor object)[edit]