threads in thread pool may be blocked by this library about usbcamera

[secile]

Hello, thank you for advice me important information.
Before I fix it, I have to understand the mechanism of Thread and ThreadPool.
I will investigate, Thank you.

[secile]

hello @Spring-grow
Could you teach me.
Is it Okey if I replace QueueUserWorkItem to 'new thread'?

public SampleGrabberCallback(DirectShow.ISampleGrabber grabber, int width, int height, int stride, bool useCache)
{
    this.BmpBuilder = new BitmapBuilder(width, height, stride, useCache);

    // create Buffered.Invoke thread.
    BufferedEvent = new System.Threading.AutoResetEvent(false);
    var thread = new System.Threading.Thread(x =>
    {
        while (true)
        {
            BufferedEvent.WaitOne(); // wait event.
            Buffered?.Invoke(GetBitmap()); // fire!
        }
    });
    thread.IsBackground = true;
    thread.Start();

    /*System.Threading.ThreadPool.QueueUserWorkItem(x =>
    {
        while (true)
        {
            BufferedEvent.WaitOne(); // wait event.
            Buffered?.Invoke(GetBitmap()); // fire!
        }
    });*/

    grabber.SetCallback(this, 1); // WhichMethodToCallback = BufferCB
}

[ARM830]

Here's the current situation: In WPF, I've initiated a camera and started capturing video. When the code for closing the camera is executed, the locations where the BufferedEvent.WaitOne() method is used might get blocked directly. In other words, after notifying the camera to shut down, the BufferCB() method is not invoked. The line if (Buffered != null) BufferedEvent.Set(); is not being used, which results in the BufferedEvent.WaitOne() method being continuously blocked. Therefore, when using Thread or ThreadPool, it is crucial to ensure that the thread generating the bitmap is closed first. This is my preliminary understanding. I am currently writing the code and preparing to verify my hypothesis.

[secile]

I decided to use new Thread instead of ThreadPool.

I noteced that Task.Run() method has TaskCreationOptions.LongRunning flag, and
if this flag is setted, Task do not use ThreadPool, but use new Thread.
This means long running thread should not use ThreadPool, but use new Thread.

This time I applied this idea.