Hello. I'm writing a little game which keeps four players connected. At first, my protocol does something like the following: -Server waits for 3 incoming connections. io_service::run is running in another thread (and the code I'll show you server side is executed after that). -Clients connect and send its data (name and team). When everything's done, the server continues and shows the received data from the clients. I have a loop like this on the Server side (with the great coroutine implementation from the examples): for (; num_players_connected_ !=3; ++num_players_connected_) { //Create context connection_contexts_.at(num_players_connected_) = std::make_shared<ConnectionContext>(service_); yield acceptor_.async_accept(*connection_contexts_.at(num_players_connected_)->socket(), std::ref(*this)); std::cout << "Servidor: Incoming connection" << std::endl; connection_contexts_.at(num_players_connected_)->start(); //This calls ClientContext::operator() //Start connection processing std::cout << "Servidor: Players connected: " << num_players_connected_ << std::endl; } //Here every connection is already done but must wait for data available in every context. std::cout << "Server: All " << num_players_connected_ << " players are connected" << std::endl; for (std::size_t i = 0; i < 3; i++) { //Wait for each player to have its data available server-side connection_contexts_.at(i)->playerDataReady().get(); std::cout << "Player info:\n"; std::cout << "\tPlayer name " << connection_contexts_.at(i)->playerName() << std::endl; std::cout << "\tPlayer team " << connection_contexts_.at(i)->playerTeam() << std::endl; } /////////////////////////////////// The Context for each client in the server side looks something like this: void ClientContext::operator()() { using namespace boost; const MsjDatosJugador * player_data = 0; MensajeRed msg; reenter (coro_opcall_state_) { yield asyncReadMessageFromSocketIntoQueue(std::ref(*this)); msg = getNextMessage(); std::cout << "Message has been read\n" << std::endl; if (msg.getTipo() == typeid(MsjDatosJugador)) { player_data = &(msg.getInfo<MsjDatosJugador>()); player_name_ = std::move(player_data->name_); player_team_ = player_data->team_; player_ready_ = true; } else { message_received_handler_(getNextMessage()); } } } void ClientContext::asyncReadMessageFromSocketIntoQueue( std::function<void ()> handler, const boost::system::error_code & ec, std::size_t bytes) { using namespace boost; if (!ec) { reenter (coro_read_state_) { message_size_ = std::make_shared<boost::int64_t>(); yield asio::async_read(*socket_, asio::buffer(message_size_.get(), sizeof(boost::int64_t)), std::bind(&GuinyoteClientContext::asyncReadMessageFromSocketIntoQueue, this, handler, std::placeholders::_1, std::placeholders::_2)); message_buffer_ = std::make_shared<std::vector<char> >(*message_size_); yield asio::async_read(*socket_, asio::buffer(message_buffer_->data(), *message_size_), std::bind(&GuinyoteClientContext::asyncReadMessageFromSocketIntoQueue, this, handler, std::placeholders::_1, std::placeholders::_2)); std::istringstream stream(std::string(message_buffer_->begin(), message_buffer_->end()), std::ios::binary); boost::archive::binary_iarchive archive(stream); MensajeRed msg; archive >> msg; std::cout << "GuinyoteClientContext: Pushing message into the message queue.\n"; messages_.push(msg); handler(); } } else { BOOST_THROW_EXCEPTION(std::runtime_error("GuinyoteContext: Error reading from client socket: " + ec.message())); } } My EXACT problem is that when the THIRD client connects, after invoking ClientContext::asyncReadMessageFromSocketIntoQueue once and reaching the first yield, it is never invoked again, even if I passed the handler function. Am I missing something? Must I flush the io_service handler execution in some way? Thanks in advance.