[Haskell-cafe] Broadcast signals between threads

[Tomasz Zielonka]

On Fri, May 25, 2007 at 07:57:45PM +0200, Joachim Breitner wrote:
> I???m writing a TCP server app ATM. It has one thread per client. Some of
> the clients want to be notified if the internal state changes, while
> others are happily chatting with the server, possible modifying the
> internal state. What I need now is a way for the chatting thread to
> signal ???anyone interested??? that the state has changed.

Did you consider using STM for thread synchronisation and communication?
STM uses change notifications (or something similar) internally to
implement the "retry" operation. I might be just what you need, but more
high level.

Best regards
Tomek