deduction guides for std::ranges::subrange

 

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Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range primitives
iterator_tsentinel_t	range_size_trange_difference_t	range_reference_trange_rvalue_reference_t	range_value_t
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range	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	single_viewviews::single	iota_viewviews::iota	basic_istream_viewviews::istream
Adaptors
views::all_tviews::all ref_view owning_view common_viewviews::common reverse_viewviews::reverse views::counted zip_viewviews::zip (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)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform adjacent_viewviews::adjacent (C++23)(C++23)	filter_viewviews::filter join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split adjacent_transform_viewviews::adjacent_transform (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< std::input_or_output_iterator I, std::sentinel_for<I> S > subrange(I, S) -> subrange<I, S>;	(1)	(since C++20)
template< std::input_or_output_iterator I, std::sentinel_for<I> S > subrange(I, S, /*make-unsigned-like-t*/<std::iter_difference_t<I>>) ->     subrange<I, S, ranges::subrange_kind::sized>;	(2)	(since C++20)
template< ranges::borrowed_range<R> > subrange(R&&) ->     subrange<ranges::iterator_t<R>, ranges::sentinel_t<R>,              (ranges::sized_range<R> ||               std::sized_sentinel_for<ranges::sentinel_t<R>,               ranges::iterator_t<R>>) ?              ranges::subrange_kind::sized : ranges::subrange_kind::unsized>;	(3)	(since C++20)
template< ranges::borrowed_range<R> > subrange(R&&, /*make-unsigned-like-t*/<ranges::range_difference_t<R>>) ->     subrange<ranges::iterator_t<R>, ranges::sentinel_t<R>,              ranges::subrange_kind::sized>;	(4)	(since C++20)

These deduction guides are provided for std::ranges::subrange.

1) Deduces the template arguments from the type of iterator and sentinel. The subrange is sized if std::sized_sentinel_for<S, I> is satisfied, as determined by the default template argument.

2) Deduces the template arguments from the type of iterator and sentinel, while the size of range is specified. The subrange is always sized.

3) Deduces the template arguments from the type of range. The subrange is sized if the size can be obtained from the range or its iterator and sentinel.

4) Deduces the template arguments from the type of range, while the size of range is specified. The subrange is always sized.

The exposition-only alias template make-unsigned-like-t maps each integer-like type to its corresponding unsigned version.

Notes

While constructing the subrange object,

• for (1,2), the behavior is undefined if the iterator-sentinel pair does not denote a valid range,
• for (2,4), the behavior is undefined if the given size is not equal to the size of the range.

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 3404	C++20	meaningless deduction guides from pair-like types were provided	removed