# iter_move(std::counted_iterator)

From cppreference.com
< cpp‎ | iterator‎ | counted iterator

friend constexpr decltype(auto) iter_move( const std::counted_iterator & i ) noexcept(noexcept( ranges::iter_move (i.base()))) requires std::input_iterator <I>; |  | (since C++20)

Casts the result of dereferencing the underlying iterator to its associated rvalue reference type.

The function body is equivalent to return ranges::iter_move (i.base());.

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::counted_iterator <I> is an associated class of the arguments.

If i.count() is equal to ​0​, the behavior is undefined.

### Parameters

i | - | a source iterator adaptor

### Return value

An rvalue reference or a prvalue temporary.

### Complexity

Constant.

### Example

Run this code

    #include <iomanip>
    #include <iostream>
    #include <iterator>
    #include <string>
    #include <vector>

    void print(auto const& rem, auto const& v)
    {
        std::cout << rem << '[' << size(v) << "] {";
        for (char comma[]{0, ' ', 0}; auto const& s : v)
            std::cout << comma << std::quoted(s), *comma = ',';
        std::cout << "}\n";
    }

    int main()
    {
        std::vector<std::string> p{"Alpha", "Bravo", "Charlie"}, q;
        print("p", p);
        print("q", q);

        using RI = std::counted_iterator<std::vector<std::string>::iterator>;

        for (RI iter{p.begin(), 2}; iter != std::default_sentinel; ++iter)
            q.emplace_back(/* ADL */ iter_move(iter));

        print("p", p);
        print("q", q);
    }

Possible output:

    p[3] {"Alpha", "Bravo", "Charlie"}
    q[0] {}
    p[3] {"", "", "Charlie"}
    q[2] {"Alpha", "Bravo"}

### 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 3953 | C++20 | the return type was std::iter_rvalue_reference_t <I> | changed to decltype(auto)

### See also

iter_move (C++20) | casts the result of dereferencing an object to its associated rvalue reference type (customization point object)
iter_swap (C++20) | swaps the objects pointed to by two underlying iterators (function template)
move (C++11) | converts the argument to an xvalue (function template)
move_if_noexcept (C++11) | converts the argument to an xvalue if the move constructor does not throw (function template)
forward (C++11) | forwards a function argument and use the type template argument to preserve its value category (function template)
ranges::move (C++20) | moves a range of elements to a new location (algorithm function object)
ranges::move_backward (C++20) | moves a range of elements to a new location in backwards order (algorithm function object)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/iterator/counted_iterator/iter_move&oldid=169860"