std::ranges::lazy_split_view<V,Pattern>::begin

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Ranges library

Range access begin cbegin      end cend rbegin crbegin      rend crend size ssize      data cdata reserve_hint (C++26)         empty

Range conversions std::from_range_t std::from_range (C++23)(C++23)         to (C++23)

Dangling iterator handling dangling borrowed_iterator_t borrowed_subrange_t

Range primitives
range_size_trange_difference_trange_value_t      elements_of (C++23)	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_reference_trange_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)

Range concepts
range borrowed_range      common_range	sized_range viewable_range      view	input_range output_range forward_range	bidirectional_range      random_access_range contiguous_range	approximately_sized_range (C++26) constant_range (C++23) sized-random-access-range (C++26)

Views
view_interface	subrange

Range factories
empty_viewviews::empty	single_viewviews::single	basic_istream_viewviews::istream	iota_viewviews::iota views::indices (C++26)	repeat_viewviews::repeat (C++23)(C++23)

Range adaptors
views::all_tviews::all as_rvalue_viewviews::as_rvalue (C++23)(C++23)     filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while common_viewviews::common views::counted as_input_viewviews::as_input (C++26)(C++26)	ref_view drop_viewviews::drop drop_while_viewviews::drop_while lazy_split_viewviews::lazy_split split_viewviews::split join_viewviews::join join_with_viewviews::join_with (C++23)(C++23) concat_viewviews::concat (C++26)(C++26) cache_latest_viewviews::cache_latest (C++26)(C++26)	owning_view reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)

Range generators std::generator (C++23)

Range adaptor closure objects range_adaptor_closure (C++23)

Range adaptor objects

Helper items
copyable-box movable-box (until C++23)    (C++23)	simple-view non-propagating-cache

 

std::ranges::lazy_split_view

Member functions

lazy_split_view::lazy_split_view

lazy_split_view::base

lazy_split_view::begin

lazy_split_view::end

Nested classes

lazy_split_view::outer_iterator

lazy_split_view::outer_iterator::value_type

lazy_split_view::inner_iterator

Deduction guides

 

constexpr auto begin();	(1)	(since C++20)
constexpr auto begin() const requires ranges::forward_range<V> && ranges::forward_range<const V> && ranges::forward_range<const Pattern>;	(2)	(since C++20)

Returns an outer_iterator to the first element of the lazy_split_view.

Let base_ be the underlying view and current_ be the underlying caching object (present only if ranges::forward_range<V> is false).

1) Equivalent to

constexpr auto begin()
{
    if constexpr (ranges::forward_range<V>)
    {
        constexpr bool simple = /*simple_view*/<V> && /*simple_view*/<Pattern>;
        return /*outer_iterator*/<simple>{*this, ranges::begin(base_)};
    }
    else
    {
        current_ = ranges::begin(base_);
        return /*outer_iterator*/<false>{*this};
    }
}

2) Equivalent to return /*outer_iterator*/<true>{*this, ranges::begin(base_)};.

Return value

outer_iterator to the first element.

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 3592	C++20	lazy_split_view does not check if Pattern is a simple view	/*simple_view*/<Pattern> is examined
LWG 3599	C++20	the const overload (2) is not constrained by ranges::forward_range<const Pattern>	constrained

See also

end	returns an iterator or a sentinel to the end (public member function)
ranges::begin (C++20)	returns an iterator to the beginning of a range (customization point object)