c++ - How do I make threads run sequentially instead of concurrently?

Question

For example I want each thread to not start running until the previous one has completed, is there a flag, something like thread.isRunning()?

#include <iostream>
#include <vector>
#include <thread>
using namespace std;

void hello() {
    cout << "thread id: " << this_thread::get_id() << endl;
}

int main() {

    vector<thread> threads;

    for (int i = 0; i < 5; ++i)
        threads.push_back(thread(hello));


    for (thread& thr : threads)
        thr.join();

    cin.get();
    return 0;
}

I know that the threads are meant to run concurrently, but what if I want to control the order?

Answer 1

There is no thread.isRunning(). You need some synchronization primitive to do it. Consider std::condition_variable for example.