To join a std::jthread and wait for it to finish, you can use the join() member function. Here’s an example that demonstrates how to join a std::jthread:

#include <iostream>
#include <chrono>
#include <thread>

void workerThread()
{
    std::this_thread::sleep_for(std::chrono::seconds(2));
    std::cout << "Worker thread completed\n";
}

int main()
{
    std::jthread myThread(workerThread); // create a jthread and start executing the workerThread function

    // Do some other work while the thread is running
    std::cout << "Main thread continues...\n";
    std::this_thread::sleep_for(std::chrono::seconds(1));

    // Join the thread and wait for it to finish
    myThread.join();

    std::cout << "Main thread completed\n";

    return 0;
}

In this example, we define a workerThread function that simply sleeps for 2 seconds and then prints a message. In the main function, we create a std::jthread called myThread and pass the workerThread function as the constructor argument. This starts the execution of the workerThread in a separate thread.

We then print a message from the main thread indicating that it continues its execution. After waiting for 1 second, we call myThread.join() to join the std::jthread and wait for it to finish. This means that the main thread will block until workerThread completes its execution.

Finally, we print a message from the main thread indicating that it has completed.

Joining a std::jthread allows us to synchronize the execution of multiple threads and ensures that the main thread waits for worker threads to finish before the program ends. This can be useful in scenarios where the main thread relies on the results or side effects of the worker thread’s computation.