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Executing functions and events on different threads
f#

Hi,

I am writing some simple code using the SAPI library. I am trying to get the recognizer object to process the text on a separate thread from the main UI thread. Can I specify on which thread the event should be processed, and if so, how do I do it in F#?

type 'a trigger = 'a -> unit;;

type 'a eventPair = trigger<'a> * IEvent<'a>;;

type recognizedPair = eventPair<string>;;

type recognizer = class

val pair : recognizedPair

new() = { pair = IEvent.create() }

member x.onRecognizer(s:string) = (fst x.pair) s

member x.recognized : IEvent<string> with get() = snd(x.pair)

end;;

// this should reside on Thread 2 (separate from the main thread)

let listener = new recognizer();;

// This function should execute on a separate thread, i.e. Thread 3

let _ = listener.recognized.Add(fun s -> System.Console.WriteLine(s));;

Any help is much appreciated. Thanks.

Chris

.

Hi Chris,

Objects or values are not associated with a particular thread, therefore I don't know what is meant by "this should reside on Thread 2".

However, I think what you are looking for is a way to have event handlers run asynchronously from the thread that triggers them. The easiest way to do this is with this code:

member x.onRecognizer(s:string) = System.Threading.ThreadPool.QueueUserWorkItem(fun _ -> (fst x.pair) s)

If you need more control over the process, a more complicated approach is to create your own thread(s) dedicated to running event handlers and manage a queue to pass event messages to them.

- Greg

By on 4/7/2007 8:40 PM ()

Greg,

Thanks for the reply.

Regards

Chris

By on 4/10/2007 1:27 AM ()

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