std::tuple_element<std::ranges::subrange>

 

C++

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Feature test macros (C++20)

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Ranges library (C++20)

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Symbols index

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Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_t range_value_t	range_reference_trange_const_reference_trange_rvalue_reference_t   (C++23)	iterator_tconst_iterator_tsentinel_t (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Factories
empty_viewviews::empty iota_viewviews::iota	single_viewviews::single basic_istream_viewviews::istream	repeat_viewviews::repeat (C++23)(C++23)
Adaptors
ref_view views::all_tviews::all common_viewviews::common owning_view views::counted reverse_viewviews::reverse zip_viewviews::zip (C++23)(C++23) as_const_viewviews::as_const (C++23)(C++23) as_rvalue_viewviews::as_rvalue (C++23)(C++23)	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while zip_transform_viewviews::zip_transform (C++23)(C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)   cartesian_product_viewviews::cartesian_product (C++23)(C++23)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform adjacent_viewviews::adjacent (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) stride_viewviews::stride (C++23)(C++23)	filter_viewviews::filter join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split join_with_viewviews::join_with (C++23)(C++23) chunk_viewviews::chunk (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23)
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view

 

std::ranges::subrange

Member functions

subrange::subrange (C++20)

subrange::operator PairLike (C++20)

Observers

subrange::begin (C++20)

subrange::end (C++20)

subrange::empty (C++20)

subrange::size (C++20)

Iterator operations

subrange::advance (C++20)

subrange::next (C++20)

subrange::prev (C++20)

Deduction guides

Non-member functions

get (C++20)

Helper types

subrange_kind (C++20)

tuple_size (C++20)

tuple_element (C++20)

 

Defined in header <ranges>
template< class I, class S, ranges::subrange_kind K > struct tuple_element<0, ranges::subrange<I, S, K>>;	(1)	(since C++20)
template< class I, class S, ranges::subrange_kind K > struct tuple_element<0, const ranges::subrange<I, S, K>>;	(2)	(since C++20)
template< class I, class S, ranges::subrange_kind K > struct tuple_element<1, ranges::subrange<I, S, K>>;	(3)	(since C++20)
template< class I, class S, ranges::subrange_kind K > struct tuple_element<1, const ranges::subrange<I, S, K>>;	(4)	(since C++20)

The partial specializations of std::tuple_element for std::ranges::subrange provide compile-time access to the iterator or sentinel type of a subrange, using tuple-like syntax. They are provided for structured binding support.

1-2) Obtains the iterator type, i.e. I.

3-4) Obtains the sentinel type, i.e. S.

Member types

Member type	Definition
type	(1-2) I (3-4) S

Notes

As get functions for subrange return iterators and sentinels by value, const qualifier is not added to the result types when the subrange is const-qualified (but not voaltile-qualified).

If the subrange is volatile-qualified, the result types are also volatile-qualified because the partial specialization for volatile or const volatile types are used. Such usage is deprecated.

Example

Run this code

#include <iterator>
#include <list>
#include <ranges>
#include <type_traits>
 
int main()
{
    std::list<int> list{3, 1, 4, 1, 5, 9, 2, 6};
 
    std::ranges::subrange subrange{
        std::counted_iterator{std::begin(list), 4},
        std::default_sentinel
    };
 
    static_assert(
        std::is_same_v<
            std::tuple_element_t<0, decltype(subrange)>,
            // implementation-defined type:
            std::counted_iterator<std::_List_iterator<int>>
            >);
 
    static_assert(
        std::is_same_v<
            std::tuple_element_t<1, decltype(subrange)>,
            std::default_sentinel_t
            >);
}

See also

Structured binding (C++17)	binds the specified names to sub-objects or tuple elements of the initializer
tuple_element (C++11)	obtains the element types of a tuple-like type (class template)
std::tuple_size<std::ranges::subrange> (C++20)	obtains the number of components of a std::ranges::subrange (class template specialization)