# std::uninitialized_move

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< cpp‎ | memory

Defined in header `<memory>` |  |
template< class InputIt, class ForwardIt > ForwardIt uninitialized_move( InputIt first, InputIt last, ForwardIt d_first ); | (1) | (since C++17)
template< class ExecutionPolicy, class InputIt, class ForwardIt > ForwardIt uninitialized_move( ExecutionPolicy&& policy, InputIt first, InputIt last, ForwardIt d_first ); | (2) | (since C++17)

1) Moves 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 (static_cast<void*>(std::addressof(*d_first)))
          typename std::iterator_traits<ForwardIt>::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 constructed are destroyed in an unspecified order.
2) Same as (1), but executed according to `policy`. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true

### 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 execution policy for details.
Type requirements
- `InputIt` must meet the requirements of LegacyInputIterator.
- `ForwardIt` must meet the requirements of LegacyForwardIterator.
- No increment, assignment, comparison, or indirection through valid instances of `ForwardIt` 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 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 ForwardIt>
    ForwardIt uninitialized_move(InputIt first, InputIt last, ForwardIt d_first)
    {
        typedef typename std::iterator_traits<ForwardIt>::value_type Value;
        ForwardIt current = d_first;
        try {
            for (; first != last; ++first, (void) ++current) {
                ::new (static_cast<void*>(std::addressof(*current))) Value(std::move(*first));
            }
            return current;
        } catch (...) {
            for (; d_first != current; ++d_first) {
                d_first->~Value();
            }
            throw;
        }
    }

### Example

| This section is incomplete Reason: no example

### See also

uninitialized_copy | copies a range of objects to an uninitialized area of memory (function template)
uninitialized_move_n (C++17) | moves a number of objects to an uninitialized area of memory (function template)

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