[Haskell-cafe] foreign function interface "Invalid type signature"

[Ivan Lazar Miljenovic]

On 26 August 2010 10:41, Ken Takusagawa <ken.takusagawa.2 at gmail.com> wrote:
> What am I doing wrong?
>
> module Ffi2 where
> {
> import Foreign.C.Types;
>
> foo :: CInt -> CInt;
> foo x = x;
>
> foreign export ccall foo :: CInt -> CInt;
>
> }

Did you enable the

>
> $ ghc -c Ffi2.hs
>
> Ffi2.hs:8:0: Invalid type signature

You need to call it with -XForeignFunctionInterface to enable FFI methinks.


-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com