std::uninitialized_copy(3)

NAME
std::uninitialized_copy - std::uninitialized_copy

Synopsis
   Defined in header <memory>
   template< class InputIt, class NoThrowForwardIt >
   NoThrowForwardIt uninitialized_copy( InputIt first, InputIt last, (1)
                        NoThrowForwardIt d_first );
   template< class ExecutionPolicy, class ForwardIt, class
   NoThrowForwardIt >
   NoThrowForwardIt uninitialized_copy( ExecutionPolicy&& policy, (2) (since C++17)
                        ForwardIt first, ForwardIt
   last,
                        NoThrowForwardIt d_first );
   1) Copies elements from the range [first, last) to an uninitialized memory area
   beginning at d_first as if by for (; first != last; ++d_first, (void) ++first)
       ::new (/* VOIDIFY */(*d_first))
           typename std::iterator_traits<NoThrowForwardIt>::value_type(*first);
   where /* VOIDIFY */(e) is:
   static_cast<void*>(&e) (until C++11)
   static_cast<void*>(std::addressof(e)) (since C++11)
   If an exception is thrown during the initialization, the objects already constructed
   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 participates 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 copy
   d_first - the beginning of the destination range
   policy - the execution policy to use. See execution 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 instances of
   NoThrowForwardIt may throw exceptions.
   Applying &* to a NoThrowForwardIt value must yield a pointer to its value type.
   (until C++11)

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

Complexity
   Linear in the distance between first and last.

Exceptions
   The overload with a template parameter named ExecutionPolicy reports errors 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-defined.
     * If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation
template<class InputIt, class NoThrowForwardIt> NoThrowForwardIt uninitialized_copy(InputIt first, InputIt last, NoThrowForwardIt d_first) {
    using T = typename std::iterator_traits<NoThrowForwardIt>::value_type;
    NoThrowForwardIt current = d_first;
    try
    {
        for (; first != last; ++first, (void) ++current)
            ::new (static_cast<void*>(std::addressof(*current))) T(*first);
        return current;
    }
    catch (...)
    {
        for (; d_first != current; ++d_first)
            d_first->~T();
        throw;
    } }

Example
// Run this code
 #include <cstdlib>
 #include <iostream>
 #include <memory>
 #include <string>
 int main()
 {
     const char *v[] = {"This", "is", "an", "example"};
     auto sz = std::size(v);
     if (void *pbuf = std::aligned_alloc(alignof(std::string), sizeof(std::string) * sz))
     {
         try
         {
             auto first = static_cast<std::string*>(pbuf);
             auto last = std::uninitialized_copy(std::begin(v), std::end(v), first);
             for (auto it = first; it != last; ++it)
                 std::cout << *it << '_';
             std::cout << '\n';
             std::destroy(first, last);
         }
         catch (...) {}
         std::free(pbuf);
     }
 }

Output:
 This_is_an_example_
   Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
      DR Applied to Behavior as published Correct behavior
                       given T as the value type of
   LWG 866 C++98 NoThrowForwardIt, if uses global replacement-
                       T::operator new exists, the program new instead
                       might be ill-formed
                       the effect description used a for loop
                       with the iteration discards the value
   LWG 2133 C++98 expression ++d_first, ++first, which of one operand
                       results to disable that ADL
                       in an argument-dependent lookup of
                       operator,
   LWG 2433 C++11 this algorithm might be hijacked by uses std::addressof
                       overloaded operator&
   LWG 3870 C++20 this algorithm might create objects on kept disallowed
                       a const storage

See also
   uninitialized_copy_n copies a number of objects to an uninitialized area of
   (C++11) memory
                        (function template)
   ranges::uninitialized_copy copies a range of objects to an uninitialized area of
   (C++20) memory
                        (niebloid)