Remix.run Logo
Remix clone Hacker News
new | show | ask | jobsGithub
▲ ben-schaaf 9 hours ago

No, it is not statically knowable if it is actually moved.

    void foo(Obj && arg) {}
Does not move `arg`. It's fairly easy to write code that assumes `std::move` moves the value, but that can lead to bugs. For example:

    void some_function(std::vector<int> &&);
    void some_function2(std::vector<int> &&);

    void main() {
        std::vector<int> a = { 1 };
        some_function(std::move(a));

        a.push_back(2);
        some_other_function(std::move(a));
    }
The expectation is that `some_other_function` is always called with `{ 2 }`, but this will only happen if `some_function` actually moves `a`.
▲adrianN 5 hours ago | parent [-]

Is pushing to a moved-from vector even legal? I thought in general the only guarantee you have after a move is that is save to destruct the object.