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);

If an exception is thrown during the initialization, the objects already constructed are destroyed in an unspecified order.

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

Parameters

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.

Notes

Possible implementation

template<class InputIt, class NoThrowForwardIt>
constexpr 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

#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);
    }
}

Defect reports

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

See also