abort a thread or just let it to be cleaned by the computer?

Question

I have the following code, I want to abort a thread if it is unfinished in 2 secs. You can see from the first code that i create a new myThread evertyime in the while loop and do not abort it. Well, I dont want to it to be like this, but if i take the myThread outside the loop and use the abort() function as the second code does. there will be error in aborting.

while (true)
        {

            try
            {
                m_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//reset up socket
                myThread = new System.Threading.Thread(new System.Threading.ThreadStart(socket_connect));
                myThread.Start();
                if (!myThread.Join(2000))
                {
                    throw new SocketException(SocketError.AccessDenied);
                }

            }
            catch (Exception ex)
            {
                m_socket.Close();
            }
        }
    }
     private static void socket_connect()
    {
        m_socket.Connect(remoteEndPoint);//Connect to remote device  
    }

I was trying the following code at first, however it give threadabortexceptions.

 myThread = new System.Threading.Thread(new System.Threading.ThreadStart(socket_connect));   
  while (true)
        { try
            {
                m_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream,     ProtocolType.Tcp);//reset up socket

                myThread.Start();
                if (!myThread.Join(2000))
                {

                    myThread.Abort();
                    throw new SocketException(SocketError.AccessDenied);
                }
            }
            catch (Exception ex)
            {
                m_socket.Close();
            }
        }
    }
    private static void socket_connect()
    {
        m_socket.Connect(remoteEndPoint);//Connect to remote device  
    }

I know abort() is not a good idea so I turn to let the threads stay and let C#(.Net? I dont know who actually does that) dealing with the garbage collection. And can anyone tell if it is a good idea since this program will be run on a board which does not have lots of memory for holding bunches of threads. And can someone tell me how exactly the garbage collection is done in C#? for example the threads.
Another thing need to be mention is that i dont have the Task class, or the socket.beginconnect() method, I guess its because i'm building a program that is going to run on a small board, not a pc. The board is a netduido plus and I'm building my project on a netduino plus platform.

Answer 1

I have the following code, I want to abort a thread if it is unfinished in 2 secs.

Reading into the code, it looks like you actually want to attempt to connect a socket to a resource within two seconds. If more than two seconds elapses, you want to move on.

I'm mostly reproducing the code in this answer, I believe this is approximately what you should be doing to achieve your goal, rather than spinning up a thread and aborting it:

Socket socket = new Socket(AddressFamily.InterNetwork,
                           SocketType.Stream,
                           ProtocolType.Tcp);

// Connect using a timeout (2 seconds)

IAsyncResult result = socket.BeginConnect( sIP, iPort, null, null );

bool success = result.AsyncWaitHandle.WaitOne( 2000, true );

if ( !success )
{
            // NOTE, MUST CLOSE THE SOCKET

            socket.Close();
            throw new ApplicationException("Failed to connect server.");
}

// Success
//... 

Answer 2

[edit: massive copypasta fail when untabbing/spacing]

Oh, please use the Task library, it's way easier to deal with these situations:

(LINQPad-friendly blob)

void Main()
{
    var canceller = new CancellationTokenSource();
    var task = Task.Factory.StartNew(() => DoStuff(canceller.Token), canceller.Token);        
    if(!task.Wait(2000, canceller.Token))
    {
        canceller.Cancel();
        task.Wait(2);
    }
    sw.Elapsed.Dump();
}
private Stopwatch sw;
private void DoStuff(CancellationToken token)
{
    try
    {
        sw = Stopwatch.StartNew();
        while(!token.IsCancellationRequested)
        {       
        }
    }
    // no catch - rethrown exceptions must be checked on Task
    finally
    {
        sw.Stop();
    }
}

Alternatively, you can use some "exit flag" condition - a bool that both your thread-starter and your thread-runner can see/alter, and use that in your while condition.