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{- 
     Error description:

     In windows xp sp2 with ghc-6-4, GHCi ends with 
        "internal error: deadlock: main thread blocked in a 
strange way"
     In RedHat Linux, it just blocks.
     A probably cause, it's that the scheduler hasn't yet 
run oneThread
     before the second putTMVAr, because no memory 
allocation has been
     requested.
     Try on the calls forkIO and runInUnboundThread.

     contact info: leonelfl@yahoo.com
-}
import Control.Concurrent
import Control.Concurrent.STM
import Control.Concurrent.STM.TMVar
main = do
   stopFlag <- atomically (do t <- newEmptyTMVar; 
return t)
   threadDelay 100001
   --t <- forkIO $ oneThread stopFlag   -- this line would 
work fine...
   -- but the following one doesn't work.
   runInUnboundThread $ oneThread stopFlag
   threadDelay 100002
   atomically ( putTMVar stopFlag True )
   threadDelay 500003
   atomically ( putTMVar stopFlag False )
   return ()

oneThread stopFlag = do
   go <- atomically ( takeTMVar stopFlag )
   if  go  then  do putStrLn "-" 
                    oneThread stopFlag
	   else  return ()

   

Trac metadata

Trac field	Value
Version	6.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	libraries (other)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture