How to detect disconnected user from CFSocket?

[BlueGooGames]

I'm setting up a multiplayer game with CFSockets and CFStreams. Everything is working smoothly and I'm sending data back and forth between server and clients. The problem is I get no notification when a client disconnects.

I got the code from the book Beginning iPhone Games Development and here is a part when a new client connects:

static void serverAcceptCallback(CFSocketRef socket, CFSocketCallBackType type,
    CFDataRef address, const void *data, void *info) {
  SocketServer *server = (SocketServer*)info;
  
  // We can only process "connection accepted" calls here
  if ( type != kCFSocketAcceptCallBack ) {
    return;
  }
  
  // for AcceptCallBack, the data parameter is a pointer to a CFSocketNativeHandle
  CFSocketNativeHandle handle = *(CFSocketNativeHandle*)data;
  Connection *connection = [[[Connection alloc]
      initWithNativeSocketHandle:handle] autorelease];

  if ( [connection connect] ) {
    [server.delegate newClientConnected:connection];
  }
}

My question is, do I need to ping the user once in a while, and if he does not respond in like 10 seconds, assume he's disconnected?

There are several reasons why he might be disconnected:
- Quit hosted game (from a button in the game)
- Quit app
- Got phonecall
- Network error maybe

So how is a good way to catch a disconnect? It would be neat if there was a function like the one above.

Thanks!

[smithdale87]

Have you tried looking in the CFSocket class reference? -- CFSocket class reference

I don't see any sort of callback for when a client gets disconnected, but I do see a method called CFSocketIsValid, which "Returns a Boolean value that indicates whether a CFSocket object is valid and able to send or receive messages."

Seems to me that this could be useful, but you might have to implement the client polling approach you were mentiongin, just not necessarily have to wait X seconds for a response.

[BlueGooGames]

Yes, I've been studiying that page to no avail. I also see the function CFSocketIsValid, but I'm not sure how to use it.

I think the server is the socket, and that is valid all the time. But the connections with the clients are the ones I need to check. Do you think I'm understanding this enough? Networking is a pretty hefty subject, but it's fun to learn

[BlueGooGames]

I found that I got the connection closed trigger, just that when I sent the program in the background on the client device, the connection is still open. But as soon as I really quit the app, I get read errors, which causes the connection to get detected as closed.

Just in case anyone is doing the same thing