std::ranges::viewable_range

 

C++

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Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

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Technical specifications

Symbols index

External libraries

 

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_viewistream_view
Adaptors
views::all_tviews::all common_viewviews::common filter_viewviews::filter reverse_viewviews::reverse	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform	join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split ref_view views::counted
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view

 

Defined in header <ranges>
template<class T>   concept viewable_range =     ranges::range<T> &&     ((ranges::view<std::remove_cvref_t<T>> &&       std::constructible_from<std::remove_cvref_t<T>, T>) ||      (!ranges::view<std::remove_cvref_t<T>> && ranges::borrowed_range<T>));		(since C++20)

The viewable_range concept is a refinement of range that describes a range that can be safely converted into a view.

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 3481	C++20	viewable_range accepted an lvalue of a move-only view	rejects