作為Boost.Asio的初學者，我對感到困惑io_service::run()。如果有人可以向我解釋此方法的阻止/解除阻止，我將不勝感激。文檔指出：該run()函數將阻塞，直到所有工作完成并且不再有要分派的處理程序，或者直到io_service停止為止。多個線程可以調用該run()函數來建立線程池，線程池io_service可以從中執行處理程序。池中等待的所有線程都是等效的，并且io_service可以選擇其中任何一個來調用處理程序。從該run()函數正常退出意味著該io_service對象已停止（該stopped()函數返回true）。后續調用run()，run_one()，poll()或poll_one()將除非有預先調用立即返回reset()。以下陳述是什么意思？[...]不再派遣處理程序[...]在嘗試了解的行為時io_service::run()，我遇到了這個示例（示例3a）。在其中，我觀察到這些io_service->run()障礙并等待工作指令。// WorkerThread invines io_service->run()void WorkerThread(boost::shared_ptr<boost::asio::io_service> io_service);void CalculateFib(size_t);boost::shared_ptr<boost::asio::io_service> io_service(    new boost::asio::io_service);boost::shared_ptr<boost::asio::io_service::work> work(   new boost::asio::io_service::work(*io_service));// ...boost::thread_group worker_threads;for(int x = 0; x < 2; ++x){  worker_threads.create_thread(boost::bind(&WorkerThread, io_service));}io_service->post( boost::bind(CalculateFib, 3));io_service->post( boost::bind(CalculateFib, 4));io_service->post( boost::bind(CalculateFib, 5));work.reset();worker_threads.join_all();但是，在我正在處理的以下代碼中，客戶端使用TCP / IP連接，并且run方法將阻塞，直到異步接收數據為止。typedef boost::asio::ip::tcp tcp;boost::shared_ptr<boost::asio::io_service> io_service(    new boost::asio::io_service);boost::shared_ptr<tcp::socket> socket(new tcp::socket(*io_service));// Connect to 127.0.0.1:9100.tcp::resolver resolver(*io_service);tcp::resolver::query query("127.0.0.1",                            boost::lexical_cast< std::string >(9100));tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);socket->connect(endpoint_iterator->endpoint());// Just blocks here until a message is received.socket->async_receive(boost::asio::buffer(buf_client, 3000), 0,                      ClientReceiveEvent);io_service->run();// Write response.boost::system::error_code ignored_error;std::cout << "Sending message \n";boost::asio::write(*socket, boost::asio::buffer("some data"), ignored_error);run()在下面的兩個示例中對其描述其行為的任何解釋將不勝感激。