[RESOLVED] Multi-Threaded TCP Server - threads do not close...

Hello,

Below is the portion of my TCP server. The problem I am experiencing is that threads are not closed properly. My understanding was that after the given Sub completes, then the thread closes. In my program for some reason about 30% of the threads created, are never being closed. I am looking at the Task Manager and they just keep going up.

Can someone look over at my code and see if I am making any obvious mistakes? How can I find out and kill old/inactive threads?

Thanks!

Code:

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Private Sub StartTCPListenerMultiThreaded()
        Dim localAddr As IPAddress = IPAddress.Parse(ip)
        TCPserver = New Sockets.TcpListener(localAddr, listeningPort)
        TCPserver.Start()                       
        While True
                If TCPserver.Pending Then
                        Dim t As Thread
                        t = New Thread(AddressOf Me.acceptingThread)
                        t.Start()
                End If
                System.Threading.Thread.Sleep(20)
        End While
End Sub

Private Sub acceptingThread()
        Dim client As TcpClient = TCPserver.AcceptTcpClient
        Dim stream As NetworkStream = client.GetStream
        client.ReceiveTimeout = 90000
        client.SendTimeout = 90000
       
        While client.Connected
                Dim bytes(1) As Byte
                Dim i As Int32
                        i = stream.Read(bytes, 0, bytes.Length)
                        While (i <> 0)
                                'do something here with received payload
                                If stream.DataAvailable = False Then
                                        Exit While
                                End If
                                i = stream.Read(bytes, 0, bytes.Length)
                        End While       
        End While
       
End Sub

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My first thought would be that whilst you exit the outer while loop when the client is no longer connected, that probably happens while you are waiting to read a byte from the socket. Since the client has disconnected, it is never going to send that byte, and so the thread is stuck on the Read call for ever?

Quote:

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Originally Posted by Evil_Giraffe

My first thought would be that whilst you exit the outer while loop when the client is no longer connected, that probably happens while you are waiting to read a byte from the socket. Since the client has disconnected, it is never going to send that byte, and so the thread is stuck on the Read call for ever?

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Hmmm... that might be it.
When I debug the program stops on this line:

i = stream.Read(bytes, 0, bytes.Length)

If the socket is open, I am waiting for an incoming message. But let's say the client disconnects - then I have no way of knowing that.
How can I timeout this thread?

I've read in so many places that aborting threads is a bad idea. I just don't know how to kill all of those threads with those broken connections.

Most examples I've seen on-line are using the above stream.read... can anyone suggest some other way?...

Sorry I can't help, just wanted to stop by and say awesome name. My name is the same and it's not one you see too often, lol. Maybe you are me in another dimension :|

Use BeginRead instead. Its asynchronous and hence wouldn't block. However, you will have to make that sub a little more complicated. The fact that it requires a callback procedure for receiving data is one complication. I think its worth it.

I found the problem.

Code:

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While client.Connected

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Above line was causing this loop to continue even when the client disconnected!
I just added a safety check - simple timeout which breaks the while loop if no data is transmitted over 2 hours (which works perfect in my case).

Thanks everyone for help!