std::make_move_iterator(3)

💅 NAME 💅

std::make_move_iterator(3) — bestie, welcome to the std::make_move_iterator page from the C++ Standard Libary manual, and it's literally here to hand you the move-iterator glow-up ✨

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🦋 Synopsis 🦋

okay so first things first: it's defined in header <iterator> 🫶

Defined in header <iterator>
template< class Iter >
(since C++11)
std::move_iterator<Iter> make_move_iterator( Iter i );
(until C++17)
template< class Iter >
(since C++17)
constexpr std::move_iterator<Iter> make_move_iterator( Iter i );

make_move_iterator is a convenience function template that constructs a std::move_iterator for the given iterator i with the type deduced from the type of the argument. no cap, that's the whole serve 💅

🎀 Parameters 🎀

• i — input iterator to be converted to move iterator

🌸 Return value 🌸

A std::move_iterator which can be used to move from the elements accessed through i. she's giving access-with-a-move-vibe, periodt.

✨ Possible implementation ✨

here's the possible-implementation mood board, and yes the code is exact:

template<class Iter>
constexpr std::move_iterator<Iter> make_move_iterator(Iter i)
{
    return std::move_iterator<Iter>(std::move(i));
}

💖 Example 💖

// Run this code 👈 that's what the page says right before the code, so we're keeping it.

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

auto print = [](auto const rem, auto const& seq)
{
    for (std::cout << rem; auto const& str : seq)
        std::cout << std::quoted(str) << ' ';
    std::cout << '\n';
};

int main()
{
    std::list<std::string> s{"one", "two", "three"};

    std::vector<std::string> v1(s.begin(), s.end()); // copy

    std::vector<std::string> v2(std::make_move_iterator(s.begin()),
                                std::make_move_iterator(s.end())); // move

    print("v1 now holds: ", v1);
    print("v2 now holds: ", v2);
    print("original list now holds: ", s);
}

🌈 Possible output 🌈

v1 now holds: "one" "two" "three"
v2 now holds: "one" "two" "three"
original list now holds: "" "" ""

🫶 Defect reports 🫶

okay so the following behavior-changing defect reports were applied retroactively to previously published C++ standards:

• LWG 2061 — applied to C++11. behavior as published: make_move_iterator did not convert array arguments to pointers. correct behavior: made to convert.

👑 See also 👑

• move_iterator — iterator adaptor which dereferences to an rvalue; since C++11, class template.
• move — obtains an rvalue reference; since C++11, function template.

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source: http://cppreference.com · version/date: 2024.06.10 — mwah, bestie 💋