std:: uninitialized_move_n

1) Copies the elements from first + [ ​ 0 ​ , count ) (using move semantics if supported) to an uninitialized memory area beginning at d_first as if by

for ( ; count > 0 ; ++ d_first, ( void ) ++ first, -- count )
:: new ( voidify ( * d_first ) )
typename std:: iterator_traits < NoThrowForwardIt > :: value_type ( /* value */ ) ;
return { first, d_first } ;

where /* value */ is std :: move ( * first ) if * first is of an lvalue reference type, or * first otherwise.

If an exception is thrown during the initialization, some objects in first + [ ​ 0 ​ , count ) are left in a valid but unspecified state, and the objects already constructed are destroyed in an unspecified order.

2) Same as (1) , but executed according to policy .

This overload participates in overload resolution only if all following conditions are satisfied:

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)

template<class InputIt, class Size, class NoThrowForwardIt>
constexpr std::pair<InputIt, NoThrowForwardIt>
    uninitialized_move_n(InputIt first, Size count, NoThrowForwardIt d_first)
{
    using ValueType = typename std::iterator_traits<NoThrowForwardIt>::value_type;
    NoThrowForwardIt current = d_first;
    try
    {
        for (; count > 0; ++first, (void) ++current, --count) {
            auto addr = static_cast<void*>(std::addressof(*current));
            if constexpr (std::is_lvalue_reference_v<decltype(*first)>)
                ::new (addr) ValueType(std::move(*first));
            else
                ::new (addr) ValueType(*first);
        }
    }
    catch (...)
    {
        std::destroy(d_first, current);
        throw;
    }
    return {first, current};
}

#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[]{"One", "Definition", "Rule"};
    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_n(std::begin(in), sz, 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);
    }
}

initially, in: "One" "Definition" "Rule" 
after move, in: "" "" "" 
after move, out: "One" "Definition" "Rule"