NAME¶

iter_move(std::common_iterator) - iter_move(std::common_iterator)

Synopsis¶

friend constexpr decltype(auto) iter_move( const std::common_iterator&
i )
(since
noexcept(noexcept(ranges::iter_move(std::declval<const I&>())) C++20)

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
std::ranges::iter_move(std::get<I>(i.var));.

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

If i.var does not hold an I object (i.e. an iterator), 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 (int o{}; auto const& s : v)
std::cout << (o++ ? ", " : "") << std::quoted(s);
std::cout << " }\n";
}

int main()
{
std::vector<std::string> p{"Andromeda", "Cassiopeia", "Phoenix"}, q;
print("p", p);
print("q", q);

using CTI = std::counted_iterator<std::vector<std::string>::iterator>;
using CI = std::common_iterator<CTI, std::default_sentinel_t>;
CI last{std::default_sentinel};

for (CI first{{p.begin(), 2}}; first != last; ++first)
q.emplace_back(/* ADL */ iter_move(first));

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

Possible output:¶

p[3] { "Andromeda", "Cassiopeia", "Phoenix" }
q[0] { }
p[3] { "", "", "Phoenix" }
q[2] { "Andromeda", "Cassiopeia" }

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)

See also¶

iter_move casts the result of dereferencing an object to its associated
(C++20) rvalue reference type
(customization point object)
iter_move casts the result of dereferencing the underlying iterator to
(C++20) its associated rvalue reference type
(function)
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)