Cannot shutdown cleanly

[ArosPrince]

Hello, I know this kind of questions get asked quite often, but I just don't see, what I am doing wrong...

I have the server running in a separate thread so that the run() method does not block the main thread.

I know that if I stop_listening() and close all the opened connections, the run() method should simply exit.

But it doesn't. I can't really tell where it gets stuck because for some reason, I don't see the stack frames for this thread in VS.

So, I create my server simply like this:

m_server.listen(port);
m_server.start_accept();
serverThread = std::thread([this]() {
	m_server.run();
});	

And in the server desctructor I have the following:

std::unique_lock<std::mutex> lock(m);
m_server.stop_perpetual();  // just in case
m_server.stop_listening();
for (auto it : m_connections) {
	m_server.close(it, websocketpp::close::status::going_away, "shutting down...");
}	
serverThread.join(); // it hangs here

Note that it has probably nothing to do with the connections. It happens even if there is no connection ever made during the server lifespan.

[lax1dude]

I have the same problem but with the client class, 1/10 times the remote server closes the connection and I call stop on the client after the connection is closed it still fails to join the thread containing the run method and it's really getting on my nerve

[lax1dude]

This is my code, currentWebsocketPPThread is a thread spawned from the client's run method

if (currentWebsocketClient && !currentWebsocketClient->stopped()) {
	try {
		if (currentWebsocketClient->get_con_from_hdl(currentWebsocketConnection)->get_state() != websocketpp::session::state::value::closed){
			currentWebsocketClient->get_con_from_hdl(currentWebsocketConnection)->close(websocketpp::close::status::going_away, string("disconnected"));
		}
		while (currentWebsocketClient->get_con_from_hdl(currentWebsocketConnection)->get_state() != websocketpp::session::state::value::closed) {
			this_thread::sleep_for(20ms);
		}
	}catch (exception& ee) {
		// go figure
	}

	if (currentWebsocketPPThread != nullptr) {
		currentWebsocketClient->stop();
		currentWebsocketClient = nullptr;
		if (currentWebsocketPPThread->joinable()) currentWebsocketPPThread->join();
		delete currentWebsocketPPThread;
		currentWebsocketPPThread = nullptr;
	}
}

[guoh27]

Is it solved?

[ArosPrince]

Sorry, I have no idea. It's been so long. I had even troubles figuring out which project I used it for.

Anyway, I located the project in the end and this is the current destructor I have. It even contains a comment (unlike the version in the OP):

	std::unique_lock<std::mutex> lock(m);
	m_server.stop_perpetual();
	m_server.stop_listening();
	for (auto it : m_connections) {
		m_server.close(it, websocketpp::close::status::going_away, "shutting down...");
	}

	m_server.stop();
	serverThread.join(); //TODO it hangs here if the above line is not called

Apparently I tried to add m_server.stop(); call before calling join().

So maybe it is solved, sorry, I don't have the HW to test it with anymore, but maybe it will help someone.