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std::ranges::owning_view(3)    C++ Standard Libary   std::ranges::owning_view(3)

NAME
     std::ranges::owning_view - std::ranges::owning_view

Synopsis
	Defined in header <ranges>
	template< ranges::range R >

	    requires  std::movable<R>  &&  (!/*is-initializer-list*/<R>)  (since
     C++20)
	class owning_view

	    : public ranges::view_interface<owning_view<R>>

	owning_view is a view that has unique ownership of a range. It is  move-
     only and
	stores that range within it.

	The  constant  /*is-initializer-list*/<R> in the requires-clause is true
     if and only
	if std::remove_cvref_t<R> is a specialization of std::initializer_list.

Member functions
	constructor   constructs an owning_view by value-initializing  or  move-
     constructing
	(C++20)       the stored range
		      (public member function)
	operator=     move-assigns the stored range
	(C++20)       (public member function)
	base	      returns a reference to the stored range
	(C++20)       (public member function)
	begin	      returns the beginning iterator of the stored range
	(C++20)       (public member function)
	end	      returns the sentinel of the stored range
	(C++20)       (public member function)
	empty	      checks whether the stored range is empty
	(C++20)       (public member function)
	size	      returns the size of the stored sized_range
	(C++20)       (public member function)
	data	       returns	the  pointer to the beginning of the stored con-
     tiguous_range
	(C++20)       (public member function)
	      Inherited from std::ranges::view_interface
	cbegin	      returns a constant iterator to the beginning of the range.
	(C++23)       (public member function of std::ranges::view_interface<D>)
	cend	      returns a sentinel for the constant iterator of the range.
	(C++23)       (public member function of std::ranges::view_interface<D>)
	operator bool returns whether the derived view is not empty. Provided if
	(C++20)       ranges::empty is applicable to it.
		      (public member function of std::ranges::view_interface<D>)
	front	      returns the first element in the derived view. Provided if
     it
	(C++20)       satisfies forward_range.
		      (public member function of std::ranges::view_interface<D>)
	back	      returns the last element in the derived view. Provided  if
     it satisfies
	(C++20)       bidirectional_range and common_range.
		      (public member function of std::ranges::view_interface<D>)
	operator[]     returns the n^th element in the derived view. Provided if
     it satisfies
	(C++20)       random_access_range.
		      (public member function of std::ranges::view_interface<D>)

     std::ranges::owning_view::owning_view

	owning_view()  requires  std::default_initializable<R>	=  default;  (1)
     (since C++20)
	owning_view(  owning_view&&  other  )  =  default;		     (2)
     (since C++20)
	constexpr  owning_view(  R&&  t  );				     (3)
     (since C++20)
	owning_view(  const  owning_view&  )  =  delete;		     (4)
     (since C++20)

	1) Default constructor. Value-initializes the stored range  by	its  de-
     fault member
	initializer (= R()).
	2)  Move  constructor.	Move  constructs  the  stored range from that of
     other.
	3) Move constructs the stored range from t.
	4) Copy constructor is deleted. owning_view is move-only.

Parameters
	other - another owning_view to move from
	t     - range to move from

     std::ranges::owning_view::operator=

	owning_view& operator=( owning_view&& other  )	=  default;  (1)  (since
     C++20)
	owning_view&  operator=(  const  owning_view&  )  = delete;   (2) (since
     C++20)

	1) Move assignment operator. Move assigns the stored range from that  of
     other.
	2) Copy assignment operator is deleted. owning_view is move-only.

Parameters
	other - another owning_view to move from

Return value
	*this

     std::ranges::owning_view::base

	constexpr R& base() & noexcept; 	      (1) (since C++20)
	constexpr const R& base() const & noexcept;   (2) (since C++20)
	constexpr R&& base() && noexcept;	      (3) (since C++20)
	constexpr const R&& base() const && noexcept; (4) (since C++20)

	Returns a reference to the stored range, keeping value category and
	const-qualification.

	1,2) Equivalent to return r_;.
	3,4) Equivalent to return std::move(r_);.

     std::ranges::owning_view::begin

	constexpr ranges::iterator_t<R> begin();		      (1) (since
     C++20)
	constexpr auto begin() const requires ranges::range<const R>; (2) (since
     C++20)

	Equivalent to return ranges::begin(r_);.

     std::ranges::owning_view::end

	constexpr  ranges::sentinel_t<R>  end();		      (1) (since
     C++20)
	constexpr auto end() const requires ranges::range<const R>;  (2)  (since
     C++20)

	Equivalent to return ranges::end(r_);.

     std::ranges::owning_view::empty

	constexpr  bool  empty() requires requires { ranges::empty(r_); };   (1)
     (since C++20)
	constexpr bool empty() const requires requires	{		     (2)
     (since C++20)
	ranges::empty(r_); };

	Equivalent to return ranges::empty(r_);.

     std::ranges::owning_view::size

	constexpr  auto  size() requires ranges::sized_range<R>;	     (1)
     (since C++20)
	constexpr auto size() const requires ranges::sized_range<const	R>;  (2)
     (since C++20)

	Equivalent to return ranges::size(r_);.

     std::ranges::owning_view::data

	constexpr  auto  data() requires ranges::contiguous_range<R>;	     (1)
     (since C++20)
	constexpr auto data() const  requires				     (2)
     (since C++20)
	ranges::contiguous_range<const R>;

	Equivalent to return ranges::data(r_);.

	Helper templates

	template< class T >

	inline				 constexpr			    bool
     (since C++20)
	enable_borrowed_range<std::ranges::owning_view<T>> =

	    std::ranges::enable_borrowed_range<T>;

	This specialization  of  std::ranges::enable_borrowed_range  makes  own-
     ing_view satisfy
	borrowed_range when the underlying range satisfies it.

Example
     // Run this code

      #include <cassert>
      #include <iostream>
      #include <ranges>
      #include <string>

      int main()
      {
	  using namespace std::literals;
	  std::ranges::owning_view  ov{"cosmos"s};  //	the deduced type of R is
     std::string;
						  // `ov` is the only  owner  of
     this string
	  assert(
	      ov.empty() == false &&
	      ov.size() == 6 &&
	      ov.size() == ov.base().size() &&
	      ov.front() == 'c' &&
	      ov.front() == *ov.begin() &&
	      ov.back() == 's' &&
	      ov.back() == *(ov.end() - 1) &&
	      ov.data() == ov.base()
	  );

	  std::cout << "sizeof(ov): " << sizeof ov << '\n' // typically equal to
     sizeof(R)
		    << "range-for: ";
	  for (const char ch : ov)
	      std::cout << ch;
	  std::cout << '\n';

	  std::ranges::owning_view<std::string> ov2;
	  assert(ov2.empty());
      //  ov2 = ov; // compile-time error: copy assignment operator is deleted
	  ov2 = std::move(ov); // OK
	  assert(ov2.size() == 6);
      }

Possible output:
      sizeof(ov): 32
      range-for: cosmos

See also
	ranges::ref_view a view of the elements of some other range
	(C++20) 	 (class template)
	views::all_t	 a view that includes all elements of a range
	views::all	 (alias template) (range adaptor object)
	(C++20)

http://cppreference.com 	   2024.06.10	     std::ranges::owning_view(3)
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