[Haskell] Converting to Foreign types

[ROBERT DOUGLAS HOELZ]

Hello,

I want to convert a Haskell Integer (Data.Int.Int32) to a C long (Foreign.C.Types.CLong), but it seems this code here doesn't work:

intToLong :: Int32 -> Clong
intToLong num =
    let maybelong = cast num
        in if isNothing maybelong
            then
                0
            else
                fromJust maybeLong

(It always returns 0)

Could anyone give me a hint as to what the problem is?

Thanks!