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Showing content from https://en.cppreference.com/w/cpp/language/../memory/ranges/uninitialized_copy.html below:

std::ranges::uninitialized_copy, std::ranges::uninitialized_copy_result - cppreference.com

Call signature

(1) (since C++20)
(constexpr since C++26) (2) (since C++20)
(constexpr since C++26)

Helper types

(3) (since C++20)

Let \(\scriptsize N\)N be ranges::min(ranges::distance(ifirst, ilast), ranges::distance(ofirst, olast)).

1)

Constructs

\(\scriptsize N\)N

elements elements from the range

[ifirst, ilast)

to an uninitialized memory area

[ofirst, olast)

as if by

for (; ifirst != ilast && ofirst != olast; ++ofirst, (void)++ifirst)
    ::new (voidify(*ofirst)) std::remove_reference_t<std::iter_reference_t<O>>(*ifirst);
return {std::move(ifirst), ofirst};

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

If [ofirst, olast) overlaps with [ifirst, ilast), the behavior is undefined.

The function-like entities described on this page are algorithm function objects (informally known as niebloids), that is:

[edit] Parameters ifirst, ilast - the iterator-sentinel pair defining the source range of elements to copy from in_range - the range of elements to copy from ofirst, olast - the iterator-sentinel pair defining the destination range of elements out_range - the destination range [edit] Return value

As described above.

[edit] Complexity

\(\scriptsize\mathcal{O}(N)\)𝓞(N).

[edit] Exceptions

Any exception thrown on construction of the elements in the destination range.

[edit] Notes

An implementation may improve the efficiency of ranges::uninitialized_copy if the value type of the output range is TrivialType.

[edit] Possible implementation 
struct uninitialized_copy_fn
{
    template<std::input_iterator I, std::sentinel_for<I> S1,
             no-throw-forward-iterator O, no-throw-sentinel-for<O> S2>
        requires std::constructible_from<std::iter_value_t<O>, std::iter_reference_t<I>>
    constexpr ranges::uninitialized_copy_result<I, O>
        operator()(I ifirst, S1 ilast, O ofirst, S2 olast) const
    {
        O current{ofirst};
        try
        {
            for (; !(ifirst == ilast or current == olast); ++ifirst, ++current)
                ranges::construct_at(std::addressof(*current), *ifirst);
            return {std::move(ifirst), std::move(current)};
        }
        catch (...) // rollback: destroy constructed elements
        {
            for (; ofirst != current; ++ofirst)
                ranges::destroy_at(std::addressof(*ofirst));
            throw;
        }
    }
 
    template<ranges::input_range IR, no-throw-forward-range OR>
        requires std::constructible_from<ranges::range_value_t<OR>,
    constexpr ranges::range_reference_t<IR>>
        ranges::uninitialized_copy_result<ranges::borrowed_iterator_t<IR>,
                                          ranges::borrowed_iterator_t<OR>>
    operator()(IR&& in_range, OR&& out_range) const
    {
        return (*this)(ranges::begin(in_range), ranges::end(in_range),
                       ranges::begin(out_range), ranges::end(out_range));
    }
};
 
inline constexpr uninitialized_copy_fn uninitialized_copy{};
[edit] Example

Output:

{"This", "is", "an", "example"};
[edit] Defect reports

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

DR Applied to Behavior as published Correct behavior LWG 3870 C++20 this algorithm might create objects on a const storage kept disallowed [edit] See also

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