In my quest for a fuse binding for Haskell, which I really need at the moment, I have the following definition working: module HSFuse { interface stat{}; typedef int getattrT([string] char *,stat); typedef struct fuseOps { [ref] getattrT * getattr; } fuseOps; void fuse_main(int argc,[in,string,size_is(argc)]char** argv,[ref] fuseOps * op); }; but when I substitute "ref" with "unique", because some operations can be null, I get the errors below. The problem is that in the generated hs file there is data FuseOps = FuseOps {getattr :: GetattrT} which completely ignores my type declaration! Did I do something wrong? Commands invoked and errors follow, thanks for attention: ihc -fhs-to-c -fuse-ints-everywhere -c HSFuse.idl ghc -package hdirect -fglasgow-exts HSFuse.hs -c HSFuse.hs:136: Couldn't match `GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int' against `GHC.Ptr.Ptr (GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int)' Expected type: GHC.Ptr.Ptr (GHC.Ptr.Ptr (GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int)) -> GHC.Ptr.Ptr (GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int) -> GHC.IOBase.IO () Inferred type: GHC.Ptr.Ptr (GHC.Ptr.Ptr (GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int)) -> (GHC.Base.String -> Stat -> GHC.IOBase.IO GHC.Base.Int) -> GHC.IOBase.IO () In the second argument of `HDirect.writeunique', namely `writeGetattrT' In the definition of `writeFuseOps': writeFuseOps ptr (FuseOps getattr) = let pf0 = ptr pf1 = HDirect.addNCastPtr pf0 0 in HDirect.writeunique (HDirect.allocBytes (GHC.Real.fromIntegral sizeofGetattrT)) writeGetattrT pf1 getattr