Method join

3rd/asio-1.24.0/include/asio/thread.hpp:79–82

Wait for the thread to exit. * This function will block until the thread has exited. * * If this function is not called before the thread object is destroyed, the * thread itself will continue to run until completion. You will, however, * no longer have the ability to wait for it to exit. */

   * no longer have the ability to wait for it to exit.
   */
  void join()
  {
    impl_.join();
  }

private:
  detail::thread impl_;