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std::uninitialized_move(3)     C++ Standard Libary    std::uninitialized_move(3)

NAME
     std::uninitialized_move - std::uninitialized_move

Synopsis
	Defined in header <memory>
	template< class InputIt, class NoThrowForwardIt >

	NoThrowForwardIt  uninitialized_move(  InputIt first, InputIt last,  (1)
     (since C++17)

					     NoThrowForwardIt d_first );
	template< class ExecutionPolicy, class ForwardIt, class
	NoThrowForwardIt >

	NoThrowForwardIt uninitialized_move( ExecutionPolicy&&	policy,      (2)
     (since C++17)
					     ForwardIt first, ForwardIt
	last,

					     NoThrowForwardIt d_first );

	1)  Moves elements from the range [first, last) to an uninitialized mem-
     ory area
	beginning at d_first as if by
	for (; first != last; ++d_first, (void) ++first)
	    ::new (static_cast<void*>(std::addressof(*d_first)))
		typename
	std::iterator_traits<NoThrowForwardIt>::value_type(std::move(*first));
	If an exception is thrown during the  initialization,  some  objects  in
     [first, last)
	are  left in a valid but unspecified state, and the objects already con-
     structed are
	destroyed in an unspecified order.

	If   d_first   +   [0,	 std::distance(first,	last))	 overlaps   with
     (since C++20)
	[first, last), the behavior is undefined.

	2) Same as (1), but executed according to policy. This overload partici-
     pates in
	overload resolution only if

	std::is_execution_policy_v<std::decay_t<ExecutionPolicy>>    is    true.
     (until
										  C++20)
	std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>>      is
     true. (since
										  C++20)

Parameters
	first, last	      -        the range of the elements to move
	d_first 	      -        the beginning of the destination range
	policy		       -	 the execution policy to use. See execu-
     tion policy for
				       details.

Type requirements
	-
	InputIt must meet the requirements of LegacyInputIterator.
	-
	ForwardIt must meet the requirements of LegacyForwardIterator.
	-
	NoThrowForwardIt must meet the requirements of LegacyForwardIterator.
	-
	No increment, assignment, comparison, or indirection through  valid  in-
     stances of
	NoThrowForwardIt may throw exceptions.

Return value
	Iterator to the element past the last element moved.

Complexity
	Linear in the distance between first and last.

Exceptions
	The overload with a template parameter named ExecutionPolicy reports er-
     rors as
	follows:

	  *  If  execution of a function invoked as part of the algorithm throws
     an exception
	    and ExecutionPolicy is one of the standard policies,  std::terminate
     is called.
	    For  any  other  ExecutionPolicy, the behavior is implementation-de-
     fined.
	  * If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation
     template<class InputIt, class NoThrowForwardIt> NoThrowForwardIt uninitial-
     ized_move(InputIt first, InputIt last, NoThrowForwardIt d_first) {
	 using	   Value     =	   typename	std::iterator_traits<NoThrowFor-
     wardIt>::value_type;
	 NoThrowForwardIt current = d_first;
	 try
	 {
	     for (; first != last; ++first, (void) ++current)
		 ::new		  (static_cast<void*>(std::addressof(*current)))
     Value(std::move(*first));
	     return current;
	 }
	 catch (...)
	 {
	     std::destroy(d_first, current);
	     throw;
	 } }

Example
     // Run this code

      #include <cstdlib>
      #include <iomanip>
      #include <iostream>
      #include <memory>
      #include <string>

      void print(auto rem, auto first, auto last)
      {
	  for (std::cout << rem; first != last; ++first)
	      std::cout << std::quoted(*first) << ' ';
	  std::cout << '\n';
      }

      int main()
      {
	  std::string in[]{"Home", "Work!"};
	  print("initially, in: ", std::begin(in), std::end(in));

	  if (
	      constexpr auto sz = std::size(in);
	      void*	out	 =	std::aligned_alloc(alignof(std::string),
     sizeof(std::string) * sz))
	  {
	      try
	      {
		  auto first{static_cast<std::string*>(out)};
		  auto last{first + sz};
		  std::uninitialized_move(std::begin(in), std::end(in), first);

		  print("after move, in: ", std::begin(in), std::end(in));
		  print("after move, out: ", first, last);

		  std::destroy(first, last);
	      }
	      catch (...)
	      {
		  std::cout << "Exception!\n";
	      }
	      std::free(out);
	  }
      }

Possible output:
      initially, in: "Home" "Work!"
      after move, in: "" ""
      after move, out: "Home" "Work!"

	Defect reports

	The  following	behavior-changing  defect  reports were applied retroac-
     tively to
	previously published C++ standards.

	   DR	 Applied to		 Behavior as published		    Cor-
     rect behavior
	LWG 3870 C++20	    this algorithm might create objects on a const  kept
     disallowed
			    storage

See also
				   copies a range of objects to an uninitialized
     area of
	uninitialized_copy	   memory
				   (function template)
	uninitialized_move_n	   moves a number of objects to an uninitialized
     area of
	(C++17) 		   memory
				   (function template)
	ranges::uninitialized_move moves a range of objects to an  uninitialized
     area of
	(C++20) 		   memory
				   (niebloid)

http://cppreference.com 	   2024.06.10	      std::uninitialized_move(3)
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