[Haskell-cafe] Re: how to implement daemon start and stop directives?

Ertugrul Soeylemez wrote:

And to prove that IORefs do lead to a pointer race condition and hence are insecure, try the following code:

main :: IO () main = do ref <- newIORef False forkIO $ forever $ modifyIORef ref not forever $ readIORef ref >>= print

It crashes for me. I'm using GHC 6.10.1 on an Athlon 64 X2 (32 bits system). The error message reads:

test: internal error: schedule: invalid what_next field (GHC version 6.10.1 for i386_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug

Interesting. Looks like a bug in the single-threaded runtime to me: I can reproduce this crash only when compiling without the `-threaded' flag.