Hi All, Can anyone tell me what System.Exit.exitWith is actually supposed to do? As far as I can tell, it seems to be a synonym of (return ()). Okay, I'll stop being provocative and try and be helpful. So I have a web server, which like the one in The Literature(TM), essentially has a main loop: doit sok = do (reqSok,reqAddr) <- Network.Socket.accept sok forkIO (handleRequest reqSok reqAddr) doit sok This is all well and good, but how do you *stop* a server? Well, you have a request (blah blash auth blah blah) which tells it to shut down, /quit for example. I have a function to handle the quit request that looks something like: quitHandler sok addr .... = do tidyUpEverything .... sendOkResponse sok sClose sok System.Exit.exitWith ExitSuccess All nice and simple. All except one detail: it doesn't actually work. It prints exit: ExitSuccess but the "doit" loop keeps going. Of course, it goes totally spacko, because of the call to tidyUpEverything, but it doesn't exit. So, if I set an IORef/TVar inside quitHandler which I inspect either just before or just after the call to Network.Socket.accept, I could exit the loop, but that only helps once the next request comes in. I contemplated a solution involving Control.Exception.throwTo, but I actually read the doco (!) which states the following: <quote> If the target thread is currently making a foreign call, then the exception will not be raised (and hence throwTo will not return) until the call has completed. This is the case regardless of whether the call is inside a block or not. </quote> So no joy there. Ideas anyone? And is exitWith broken, or is it the doco that's broken? cheers, T. -- Dr Thomas Conway drtomc@gmail.com Silence is the perfectest herald of joy: I were but little happy, if I could say how much.