How to abort threads created with ThreadPool.QueueUserWorkItem

Question

is there a way to abort threads created with QueueUserWorkItem?

Or maybe I don't need to? What happens if the main application exits? Are all thread created from it aborted automatically?

Answer 1

You don't need to abort them. When your application exits, .NET will kill any threads with IsBackground = true. The .NET threadpool has all its threads set to IsBackground = true, so you don't have to worry about it.

Now if you're creating threads by newing up the Thread class, then you'll either need to abort them or set their IsBackground property to true.

Answer 2

However, if you are using unmanaged resources in those threads, you may end up in a lot of trouble.

That would rather depend how you were using them - if these unmanaged resources were properly wrapped then they'd be dealt with by their wrapper finalization regardless of the mechanism used to kill threads which had referenced them. And unmanaged resources are freed up by the OS when an app exits anyway.

There is a general feeling that (Windows) applications spend much too much time trying to clean-up on app shutdown - often involving paging-in huge amounts of memory just so that it can be discarded again (or paging-in code which runs around freeing unmangaged objects which the OS would deal with anyway).