I think I have raised the issue some time ago, but don't remember why it hasn't been solved as I would like to. Currently a thread which is killed displays Fail: thread killed, e.g. in the following program: import Concurrent main:: IO () main = do t <- forkIO (threadDelay 1000000) threadDelay 500000 killThread t threadDelay 500000 Since the very purpose of killThread is to kill the damn thread, I find it inconvenient to have to wrap any thread which is supposed to be killable with Exception.catch to avoid the message. Worse: it should use block and unblock, otherwise there is a small window where killing the thread will still display the message. I can probably agree that other kinds of exceptions are displayed; maybe the programmer didn't know that exceptions are being thrown and wants the diagnostic. It implies that any well-written code should catch exceptions in all threads it creates (unless he is sure that the code will not throw exceptions), since there shouldn't be compiler's error output from a correct program. Not nice but I can live with that. Should asynchronous exceptions be really displayed in threads other than the main thread? IMHO not. -- __("< Marcin Kowalczyk * qrczak@knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK