Re: GHC -O2 and unsafePerformIO

Neil Mitchell wrote:

Hi

Thanks to dcoutts, I have now come up with an answer. I don't understand why it works now, but not before. I do remember than browsing either Core or STG is not a fun thing to do...

p_System_IO_hGetChar h = trace "i am here" $ unsafePerformIO $ getCharIO h

{-# NOINLINE getCharIO #-} getCharIO h = do c <- getchar print c return $ if c == (-1) then 0 else chr_ c

This is clearly a misuse of unsafePerformIO (as I'm sure you're aware). Just out of interest - what's the context? Cheers, Simon