The HEAD now does FFI by default (Haskell 2010) so you would not have tripped over this. But even if you use the -XHaskell98 flag to recover Haskell-98 mode, you get this error: Foo.hs:9:1: Invalid type signature: foreign export ccall foo :: CInt -> CInt Perhaps you meant to use -XForeignFunctionInterface? Which would have been more helpful for you. Simon | -----Original Message----- | From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe- | bounces@haskell.org] On Behalf Of Ivan Lazar Miljenovic | Sent: 26 August 2010 01:48 | To: Ken Takusagawa | Cc: Haskell Cafe | Subject: Re: [Haskell-cafe] foreign function interface "Invalid type | signature" | | On 26 August 2010 10:41, Ken Takusagawa 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@gmail.com | IvanMiljenovic.wordpress.com | _______________________________________________ | Haskell-Cafe mailing list | Haskell-Cafe@haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe