C++11 thread doesn't work with virtual member function
c++, c++11, multithreading
Solution
You can't let an object run out of scope until you're finished using it! The `return 0;` at the end of `main` causes `fn` to go out of scope. So by the time you get around to calling `tick`, there's no guarantee the object even exists any more.
(The logic in `~Runnable` is totally broken. Inside the destructor is way too late -- the object is already at least partially destroyed.)
Problem
I'm trying to get a class run a thread, which will call a virtual member function named Tick() in a loop. Then I tried to derive a class and override the base::Tick(). but when execute, the program just call the base class's Tick instead of override one. any solutions? ``` #include <iostream> #include <atomic> #include <thread> #include <chrono> using namespace std; class Runnable { public: Runnable() : running_(ATOMIC_VAR_INIT(false)) { } ~Runnable() { if (running_) thread_.join(); } void Stop() { if (std::atomic_exchange(&running_, false)) thread_.join(); } void Start() { if (!std::atomic_exchange(&running_, true)) { thread_ = std::thread(&Runnable::Thread, this); } } virtual void Tick() { cout << "parent" << endl; }; std::atomic<bool> running_; private: std::thread thread_; static void Thread(Runnable *self) { while(self->running_) { self->Tick(); std::this_thread::sleep_for(std::chrono::milliseconds(100)); } } }; class Fn : public Runnable { public: void Tick() { cout << "children" << endl; } }; int main (int argc, char const* argv[]) { Fn fn; fn.Start(); return 0; } ``` outputs: ``` parent ```