NAME

iter_move(std::counted_iterator) - iter_move(std::counted_iterator)

Synopsis

friend constexpr decltype(auto) iter_move( const
std::counted_iterator& i )
(since C++20)
noexcept(noexcept(ranges::iter_move(i.base())))

requires std::input_iterator<I>;

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 changed to
std::iter_rvalue_reference_t<I> decltype(auto)

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