std::ranges::views::all, std::ranges::all_view

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Ranges library

Range access
begincbegin endcend	rbegincrbegin rendcrend	size empty datacdata
Range primitives
iterator_tsentinel_t	range_difference_trange_value_t	range_reference_trange_rvalue_reference_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
Semiregular wrapper
Factories
empty_viewviews::empty	single_viewviews::single	iota_viewviews::iota	views::counted
Adaptors
all_viewviews::all join_viewviews::join take_viewviews::take basic_istream_viewistream_view	ref_view                                split_viewviews::split take_while_viewviews::take_while elements_viewviews::elements	common_viewviews::common transform_viewviews::transform drop_viewviews::drop keys_viewviews::keys	reverse_viewviews::reverse filter_viewviews::filter drop_while_viewviews::drop_while values_viewviews::values

 

template <ranges::viewable_range R> using all_view = decltype(views::all(std::declval<R>()));	(1)	(since C++20)
namespace views {     inline constexpr /*unspecified*/ all = /*unspecified*/; }	(2)	(since C++20)

A range adaptor that returns a view that includes all elements of its range argument.

The expression views::all(E) is expression-equivalent (has the same effect) to:

• decay-copy(E) if the decayed type of E models view.
• Otherwise, std::ranges::ref_view{E} if that expression is well-formed
• Otherwise, std::ranges::subrange{E}

Expression-equivalent

Expression e is expression-equivalent to expression f, if e and f have the same effects, either are both potentially-throwing or are both not potentially-throwing (i.e. noexcept(e) == noexcept(f)), and either are both constant subexpressions or are both not constant subexpressions.

Example

Run this code

#include <ranges>
#include <vector>
#include <iostream>
 
int main()
{
    std::vector<int> v{0,1,2,3,4,5};
    for(int n : std::views::all(v) | std::views::take(2) ) {
        std::cout << n << ' ';
    }
}

Output:

0 1