I'm trying to expand with what some people helped me here Call function inside a lambda passed to a thread so my worker class can support a move constructor and a move operator=, but I have the problem that my class is binding this by copy (or reference) to the thread so it can access the class values. Which are several atomic<bool>, a condition_variable and a mutex.
But when I try to move it since the thread is bound to the other condition variable, mutex and atomics, anything I do on it is not working. How can I fix this?
Do I need to use a more complex object and move it around instead of a lambda so the thread can have a referenece to it? or is there another alternative.
As always help will be really appreciated :).
Here is a snippet (MWE) of the implementation.
class worker {
public:
template <class Fn, class... Args>
explicit worker(Fn func, Args... args) {
t = std::thread(
[&func, this](Args... cargs) -> void {
std::unique_lock<std::mutex> lock(mtx);
while (true) {
cond.wait(lock, [&]() -> bool { return ready; });
if (terminate)
break;
func(cargs...);
ready = false;
}
},
std::move(args)...);
}
worker(worker &&w) : t(std::move(w.t)) { /* here there is trouble */ }
worker &operator=(worker &&w) {
t = std::move(w.t);
terminate.store(wt.terminate);
ready.store(wt.ready);
return *this;
/* here too */
}
~worker() {
terminate = true;
if (t.joinable()) {
run_once();
t.join();
}
}
worker() {}
void run_once() {
std::unique_lock<std::mutex> lock(mtx);
ready = true;
cond.notify_one();
}
bool done() { return !ready; }
private:
std::thread t;
std::atomic<bool> ready, terminate; // What can I do with all these?
std::mutex mtx; //
std::condition_variable cond; //
};
int main() {
worker t;
t = worker([]() -> void { cout << "Woof" << endl; });
t.run_once();
while(!t.done()) ;
return 0;
}
Sorry for the big dump of code.
