Hi, You can't attach a finalizer to an unpointed type (here Addr#). It explains the segfault. You would have to attach the finalizer to `fptr` but it's quite fragile because GHC may remove the boxing in some cases. Sylvain On 17/09/2019 09:16, Roman Cheplyaka wrote:
Hi all,
I'd like to attach a finalizer to FunPtrs (which point to JIT-compiled functions that need to be deallocated).
However, the act of running the finalizer (no matter what it does) results in a segfault.
Here's a minimal example:
{-# LANGUAGE UnboxedTuples, MagicHash #-} import GHC.Exts (FunPtr(..)) import GHC.Base import Foreign.Ptr import System.Mem
attachFinalizer :: FunPtr a -> IO () -> IO () attachFinalizer fptr@(FunPtr addr) (IO fin) = IO $ \s0 -> case mkWeak# addr fptr fin s0 of (# s1, _ #) -> (# s1, () #)
foreign import ccall "wrapper" mkIO :: IO () -> IO (FunPtr (IO ()))
main = do fptr <- mkIO $ return () attachFinalizer fptr $ do -- The exact contents of the finalizer doesn't seem to matter putStrLn "+++ finalizer ran" freeHaskellFunPtr fptr putStrLn "+++ attached successfully" performGC
Is there a proper way to do this? (GHC 8.6.5)
Roman
_______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.