std::ranges::view::all, std::ranges::all_view

template <ViewableRange R>
using all_view = decltype(view::all(std::declval<R>()));

namespace view {
    inline constexpr /*unspecified*/ all = /*unspecified*/;
}

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

The expression view::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}

Example

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

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