NAME

std::move_iterator::base - std::move_iterator::base

Synopsis

iterator_type base() const; (since C++11)
(until C++17)
constexpr iterator_type base() const; (1) (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 base iterator.

1) Copy constructs the return value from the underlying iterator. (until C++20)
1) Returns a reference to the underlying iterator. (since C++20)

2) Move constructs the return value from the underlying iterator.

Parameters

(none)

Return value

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

2) An iterator move constructed from the underlying iterator.

Exceptions

May throw implementation-defined exceptions.

Example

// Run this code

#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:

4 3 2 1 0

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 the const version of base returns a copy of returns a reference
the underlying iterator
LWG 3593 C++20 the const version of base returns a made noexcept
reference but might not be noexcept