On 11/17/2015 02:06 PM, Johannes Waldmann wrote:

Ah, neat. I get the idea. But does it work here?

import Control.Concurrent.STM import Foreign.StablePtr main = atomically retry >>= newStablePtr

ghc -threaded -rtsopts -O2 sp.hs

./sp +RTS -N sp: thread blocked indefinitely in an STM transaction

StablePtr needs to contain the ThreadId of the current thread. myThreadId >>= newStablePtr atomically retry In your example, newStablePtr won't even be called until retry has been interrupted. Roman