Hello, I have been working with a program that uses FFI to communicate with R for several years, but today there is a segmentation fault while importing functions or data from R. Before giving up on this project, I'm posting a few detail here, in case anybody has ideas...perhaps something changed with FFI? I tried going back to the version of R and ghc where it worked using stack, but no luck. The Haskell code is a modification of the code in the package hR (by Dylan Simon), and here is a function that fails that worked before. It fails with a seg fault on the call to r_install. (s = "parse" when it fails)... foreign import ccall safe "Rf_install" r_Install :: CString -> IO R_EXP rInstall :: String -> IO REXP rInstall s = withCString s r_Install >>= extREXP The types are defined as follows... extREXP :: R_EXP -> IO REXP extREXP = newForeignPtr_ data REXPREC type R_EXP = Ptr REXPREC type REXP = ForeignPtr REXPREC newtype SEXP a = SEXP { unSEXP :: REXP } deriving (Eq, Show) Please let me know if you see anything obviously wrong and in need of improvement, perhaps because of changes to the FFI. Thanks, Dominick