# std::deque<T,Allocator>::insert_range

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< cpp‎ | container‎ | deque

template< container-compatible-range<T> R > iterator insert_range( const_iterator pos, R&& rg ); |  | (since C++23)

Inserts, in non-reversing order, copies of elements in rg before pos.

All iterators (including the end() iterator) are invalidated. References are invalidated too, unless pos == begin() or pos == end(), in which case they are not invalidated.

Each iterator in the range rg is dereferenced exactly once.

The behavior is undefined if rg overlaps with the container.

### Parameters

pos | - | iterator before which the content will be inserted (pos may be the end() iterator).
rg | - | a container compatible range, that is, an `input_range` whose elements are convertible to `T`.
Type requirements
- `T` must be EmplaceConstructible into `deque` from *ranges::begin(rg). Also, `T` must be MoveInsertable into `deque` and `T` satisfies MoveConstructible, MoveAssignable, and Swappable. Otherwise, the behavior is undefined.

### Return value

An `iterator` that points at the copy of the first element inserted into `deque` or at pos if rg is empty.

### Notes

Feature-test macro | Value | Std | Comment
--- | --- | --- | ---
`__cpp_lib_containers_ranges` | 202202L | (C++23) | Ranges-aware construction and insertion

### Example

Run this code

    #include <algorithm>
    #include <cassert>
    #include <iterator>
    #include <deque>
    #include <list>

    int main()
    {
        auto container = std::deque{1, 2, 3, 4};
        auto pos = std::next(container.begin(), 2);
        assert(*pos == 3);
        const auto rg = std::list{-1, -2, -3};

    #ifdef __cpp_lib_containers_ranges
        container.insert_range(pos, rg);
    #else
        container.insert(pos, rg.cbegin(), rg.cend());
    #endif
        assert(std::ranges::equal(container, std::deque{1, 2, -1, -2, -3, 3, 4}));
    }

### See also

insert | inserts elements (public member function)
prepend_range (C++23) | adds a range of elements to the beginning (public member function)
append_range (C++23) | adds a range of elements to the end (public member function)

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