foreign import "fooble" fooble fooble :: PackedString -> Int -> IO Int

type PackedString = ByteArray Int

With the code above I'm getting the following error: -- Unacceptable argument type in foreign declaration: PackedString -- When checking declaration: -- foreign import _ccall "fooble" fooble :: PackedString -> Int -> IO Int Is there any option that I must include when I launch ghc (I'm very new to this compiler, as to Haskell)? -- I'm trying with "ghc -c -fglasgow-exts test.hs" Best regards, Corneliu