std::ranges::subrange<I,S,K>::subrange

 

C++

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Feature test macros (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)

 

subrange() requires std::default_initializable<I> = default;	(1)	(since C++20)
constexpr subrange( /*convertible-to-non-slicing*/<I> auto i, S s )   requires (!/*store-size*/);	(2)	(since C++20)
constexpr subrange( /*convertible-to-non-slicing*/<I> auto i, S s,                     /*make-unsigned-like-t*/<std::iter_difference_t<I>> n )   requires (K == ranges::subrange_kind::sized);	(3)	(since C++20)
template< /*different-from*/<subrange> R >   requires ranges::borrowed_range<R> &&            /*convertible-to-non-slicing*/<ranges::iterator_t<R>, I> &&            std::convertible_to<ranges::sentinel_t<R>, S> constexpr subrange( R&& r ) requires (!/*store-size*/ || ranges::sized_range<R>);	(4)	(since C++20)
template< ranges::borrowed_range R>   requires /*convertible-to-non-slicing*/<ranges::iterator_t<R>, I> &&            std::convertible_to<ranges::sentinel_t<R>, S>   constexpr subrange( R&& r, /*make-unsigned-like-t*/<std::iter_difference_t<I>> n )     requires (K == ranges::subrange_kind::sized)       : subrange{ranges::begin(r), ranges::end(r), n}   {}	(5)	(since C++20)

Constructs a subrange.

If K == ranges::subrange_kind::sized && !std::sized_sentinel_for<S, I>, the size of the range is stored into the subrange, as if stored by a member subobject of type /*make-unsigned-like-t*/<std::iter_difference_t<I>>, where make-unsigned-like-t is an exposition-only alias template that maps each integer-like type to its corresponding unsigned version. Otherwise, the size is not stored. The constant store-size is true if the size is stored, false otherwise.

1) Default constructor. Value-initializes the stored iterator and sentinel as if by default member initializers = I() and = S(), respectively. If the size is stored, it is initialized with ​0​ as if by the default member initializer = 0.

2) Constructs a subrange from an iterator-sentinel pair. Initializes the stored iterator and sentinel with std::move(i) and s respectively. The behavior is undefined if [i, s) is not a valid range.

3) Constructs a subrange from an iterator-sentinel pair and a size hint. Initializes the stored iterator and sentinel with std::move(i) and s respectively. If the size is stored, it is initialized with n. The behavior is undefined if [i, s) is not a valid range, or n is not equal to ranges::distance(i, s) explicitly converted to its type.

4) Constructs a subrange from a range. Equivalent to subrange(r, static_cast</*make-unsigned-like-t*/<std::iter_difference_t<I>>>(ranges::size(r))) if the size is stored. Otherwise, equivalent to subrange(ranges::begin(r), ranges::end(r)).

5) Constructs a subrange from a range and a size hint. The behavior is undefined if n is not equal to ranges::distance(ranges::begin(r), ranges::end(r)) explicitly converted to its type.

The exposition only concept different-from is modeled by types T and U if and only if std::decay_t<T> and std::decay_t<U> are different types.

The exposition only concept convertible-to-non-slicing is satisfied or modeled by From and To if and only if std::convertible_to<From, To> is satisfied or modeled respectively, and ​any of following conditions is satisfied:

• either std::decay_t<From> or std::decay_t<To> is not a pointer type,
• std::remove_pointer_t<From>(*)[] is implicitly convertible to std::remove_pointer_t<To>(*)[], i.e., the conversion from From to To is at most a qualification conversion.

Parameters

i	-	iterator that denotes the beginning of the range
s	-	sentinel that denotes the end of the range
r	-	range
n	-	size hint, must be equal to the size of the range

Notes

The exposition-only concept convertible-to-non-slicing forbids the conversion from the pointer to derived class to the pointer to base class.

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 3470	C++20	convertible-to-non-slicing rejected some valid qualification conversions	made accepted
P2393R1	C++20	implicit conversion to an integer-class type might be invalid	made explicit