Question

I have a multithread application. I want only one thread to execute my function and other threads to pass it while my function executing. How can I do this?

My method is something like:

    public void setOutput(int value)
    {
        try
        {
            GPOs gpos = reader.Config.GPO;
            gpos[1].PortState = GPOs.GPO_PORT_STATE.TRUE;
            gpos[2].PortState = GPOs.GPO_PORT_STATE.TRUE;
            Thread.Sleep(WAIT);
            gpos[1].PortState = GPOs.GPO_PORT_STATE.FALSE;
            gpos[2].PortState = GPOs.GPO_PORT_STATE.FALSE;
        }
        catch (Exception ex)
        {
            logger.Error("An Exception occure while setting GPO to " + value + " " + ex.Message);
        }
    }

Answer 1

You can use a lock object in combination with Monitor.TryEnter.

private Object outputLock = new Object();

public void setOutput(int value)
{
    if Monitor.TryEnter(outputLock)
    {
        try
        {
            .... your code in here
        }
        finally
        {
            Monitor.Exit(outputLock);
        }
    }
}

Only one thread at at time will be allowed into the Monitor.TryEnter block. If a thread arrives here while another thread is inside, then Monitor.TryEnter returns false.