STM and unsafePerformIO

[Robert van Herk]

Never mind, I can probably use an MVar to work around this...

Robert

Robert van Herk wrote:
> Hello All,
>
> I think I've read somewhere that STM doesn't like unsafePerformIO. 
> However, I would like to use a global STM variable. Something like this:
>
> module Main where
> import GHC.Conc
> import System.IO.Unsafe
>
> tSid = unsafePerformIO (atomically (newTVar 0))
>
> tickSessionID :: STM Int
> tickSessionID =
>   do sid <- readTVar tSid
>     writeTVar tSid (sid + 1)
>     return sid
>
> main = atomically tickSessionID
>
>
>
> But, when I try this, the evaluation of main causes a segmentation 
> fault. Is there a workaround for this bug?
>
> Regards,
> Robert
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