[range.ref.view]

ref_view is a view of the elements of some other range.

namespace std::ranges { template<range R> requires is_object_v<R> class ref_view : public view_interface<ref_view<R>> { private: R* r_; // exposition only public: template<different-from<ref_view> T> requires see below constexpr ref_view(T&& t); constexpr R& base() const { return *r_; } constexpr iterator_t<R> begin() const { return ranges::begin(*r_); } constexpr sentinel_t<R> end() const { return ranges::end(*r_); } constexpr bool empty() const requires requires { ranges::empty(*r_); } { return ranges::empty(*r_); } constexpr auto size() const requires sized_range<R> { return ranges::size(*r_); } constexpr auto data() const requires contiguous_range<R> { return ranges::data(*r_); } }; template<class R> ref_view(R&) -> ref_view<R>; }

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template<different-from<ref_view> T>
  requires see below
constexpr ref_view(T&& t);

Effects: Initializes r_ with addressof(static_cast<R&>(std::forward<T>(t))).

Remarks: Let FUN denote the exposition-only functions void FUN(R&); void FUN(R&&) = delete;

The expression in the requires-clause is equivalent to: convertible_to<T, R&> && requires { FUN(declval<T>()); }

25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.6 All view [range.all]

25.7.6.2 Class template ref_view [range.ref.view]