Using emscripten_sleep for waiting to be finished

[tbuchs]

I am trying to port a c++ framework to the web. Each Client starts the application in a separate browser window and has to wait for all clients to be connected. The connection/communication between the browser windows is established via WebRTC. The WebRTC channels all work perfectly fine, however the waiting (=emscripten_sleep) somehow takes way longer to than expected.

// wait for all other players to connect  
int sleep_interval = 1000;
int time_slept = 0;
while (connected_users < nplayers and time_slept < 60*1000)
{
  cout << "connected users(" << connected_users << "/" << nplayers << ")" << endl;
  emscripten_sleep(sleep_interval);
  time_slept += sleep_interval;
}
if(connected_users < nplayers) {
  cerr << "Timeout - only " << connected_users << " clients!" << endl;
  exit(-1);
}
cout << "All clients connected!" << endl;
emscripten_websocket_close(websocket_conn, 0, "Finshed WebRTC-Connection establishment.");
emscripten_websocket_delete(websocket_conn);

The output is always different - on one browser tab it works perfectly fine, on the other it just outputs once "connected_users(1/3)" then it outputs nothing for like 2 minutes and then it outputs ("All clients connected"). Even though the debug messages for webrtc have been finished after 2 seconds.

I use -sASYNCIFY.

[tbuchs]

It is the same issue for me, when I try waiting for a message from another player.

while(message_queue == 0) {
    emscripten_sleep(100);
  }
  cerr << "received message from " << client << endl;
  o = *read_message(player);
  assert(o.get_length() > 0);
}

I get the print from the WebRTC Channel that the message is received and the loop is stuck for 2min, even though the message was already received.

[sbc100]

Where is connected_users being updated? Does marking connected_users as volatile help?

[tbuchs]

connected_users gets updated, as soon as the datachannel between the clients is established. Volatile does not change anything, however you gave me a good hint: may it be a problem, that I use the mutable keyword on the variables?

[tbuchs]

it is interesting that Firefox warns after a few seconds when the program is "stuck" with: "Title of the page" is slowing down Firefox. To speed up your browser, stop that page. And after choosing Stop the program ends the "endless" loop and runs perfectly

[tbuchs]

It is the same issue for me, when I try waiting for a message from another player.

while(message_queue == 0) {
    emscripten_sleep(100);
  }
  cerr << "received message from " << client << endl;
  o = *read_message(player);
  assert(o.get_length() > 0);
}

I get the print from the WebRTC Channel that the message is received and the loop is stuck for 2min, even though the message was already received.

I removed the mutable keyword and nothing changed. The first code works now, but this code above still has the same issue. I can't think of any difference except, that the message_queue gets updated in a callback function of webrtc (when a message is received).