[Haskell-cafe] Re: FFI documentation?

[Mauricio]

 > Where do I find the documentation  for the FFI for GHC?  I've read the
 > FFI report,  the GHC user guide  and scoured haskell.org  but they all
 > gloss over what commands you actually need to give GHC and how to give
 > them.  "foreign import blah blah" just gives me undefined references.


One well  documented and compiler independent  way to do that  is to use
Cabal packages:

http://www.haskell.org/ghc/docs/latest/html/Cabal/authors.html

as used on Hackage:

http://hackage.haskell.org

If you have  never done that, you will take some  time to understand the
role of the  setup file (which in your case  will problably be something
like: import  Distribution.Simple; main=defaultMain) and  the details of
.cabal files. (The problem you  are concerned with is detailed in 3.1.4:
Build Information. You'll  see you can also list C  files to be compiled
with your  code, and if you  are using some library  that implements the
pkg-config standard  then everything is  really, really easy.   I advise
you to  also understand well how  'build-depends' works and  how to list
language  features out  of  Haskell 98  —  in your  situation, at  least
'extensions: ForeignFunctionInterface'.)

Best,
Maurício