std::ranges::views::to_input, std::ranges::to_input_view - cppreference.com (original) (raw)

std::ranges::to_input_view

Defined in header
template< ranges::input_range V > requires ranges::view<V> class to_input_view : public ranges::view_interface<to_input_view<V>> (1) (since C++26)
namespace views { inline constexpr /* unspecified */ to_input = /* unspecified */; } (2) (since C++26)
Call signature
template< ranges::viewable_range R > requires /* see below */ constexpr ranges::view auto to_input( R&& r ); (since C++26)
  1. A range adaptor that represents a view of an underlying view as an input_range-only and not a common_range.

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

Additionally, to_input_view does not model common_range. However, it does model borrowed_range, constant_range, and sized_range when the underlying view V models respective concepts.

Contents

[edit] Data members

Member Description
V base_ (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 from std::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) [edit]
cbegin(C++23) returns a constant iterator to the beginning of the range (public member function of std::ranges::view_interface) [edit]
cend(C++23) returns a sentinel for the constant iterator of the range (public member function of std::ranges::view_interface) [edit]
operator bool returns whether the derived view is not empty, provided only if ranges::empty is applicable to it (public member function of std::ranges::view_interface) [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) [edit]
front returns the first element in the derived view, provided if it satisfies forward_range (public member function of std::ranges::view_interface) [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) [edit]
operator[] returns the nth element in the derived view, provided only if it satisfies random_access_range (public member function of std::ranges::view_interface) [edit]

std::ranges::to_input_view::to_input_view

| | (1) | (since C++26) | | | --------------------------------------------- | ------------- | ------------- | | constexpr explicit to_input_view( V base ); | (2) | (since C++26) |

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

  2. Initializes _base_ with std::move(base).

Parameters

std::ranges::to_input_view::base

| | (1) | (since C++26) | | | ---------------------- | ------------- | ------------- | | constexpr V base() &&; | (2) | (since C++26) |

  1. Copy-constructs the result from the underlying view. Equivalent to return base_;.

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

std::ranges::to_input_view::begin

constexpr auto begin() requires (!__simple_view<V>); (1) (since C++26)
constexpr auto begin() const requires ranges::range<const V>; (2) (since C++26)

  1. Equivalent to return /*iterator*/<false>(ranges::begin(base_));

  2. Equivalent to return /*iterator*/<true>(ranges::begin(base_));

std::ranges::to_input_view::end

constexpr auto end() requires (!__simple_view<V>); (1) (since C++26)
constexpr auto end() const requires ranges::range<const V>; (2) (since C++26)

1,2) Equivalent to return ranges::end(base_);

std::ranges::to_input_view::size

[edit] Deduction guides

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

[edit] Nested classes

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

[edit] Helper templates

This specialization of std::ranges::enable_borrowed_range makes to_input_view satisfy borrowed_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

[edit] See also