problems with FFI including h files

[Alastair Reid]

> I thought we established that generating valid C prototypes from the
> Haskell FFI type signature wasn't possible due to the incompleteness
> of the Haskell type (lack of 'const' modifiers for one thing - is
> there anything else?).

Compilers use the same calling sequence whether you tell them about
const or not.  

I believe that we can call all C functions correctly knowing only the
calling convention (ccall, stdcall, etc) and the Haskell type.  I
certainly hope this is true since Hugs' implementation of wrappers
depends on it.

(Hmmm, some calling conventions do funny things when passing and
returning small structs.  I don't know much about this though...)

>> This is roughly how the Hugs FFI header file will look once my
>> current hacking on it is finished.

> Looks good.

As of course it should since I stole vast swathes from GHC's HsFFI.h :-)


--
Alastair