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std::move_iterator<Iter>::base - cppreference.com

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(1)

iterator_type base() const;

 (constexpr since C++17)
(until C++20)

constexpr const iterator_type& base() const& noexcept;

 (since C++20)

constexpr iterator_type base() &&;

 (2) (since C++20)

Returns the underlying iterator.

1) Returns a copy of(until C++20)reference to(since C++20) the underlying iterator.

2) Returns an iterator move constructed from the underlying iterator.

Return value

Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

int main()
{
    std::vector<int> v{0, 1, 2, 3, 4};
    std::move_iterator<std::vector<int>::reverse_iterator>
        m1{v.rbegin()},
        m2{v.rend()};
    
    std::copy(m1.base(), m2.base(), std::ostream_iterator<int>(std::cout, " "));
    std::cout << '\n';
}

Output:

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 3391 C++20 overload (1) returned a copy of the underlying iterator returns a reference
LWG 3593 C++20 overload (1) was not noexcept made noexcept

See also