[Haskell-cafe] Re: Resolved: ffi linking problem

[jeff p]

Hello,

> If -fvia-C fixes your problem, then your code has a bug, strictly speaking.  If
> your foreign call requires some information from a header file, then the right
> way to call it is by making a small C wrapper function and calling that.
>
I tried to do this but couldn't. I could get GHC to compile and link
with warnings of the form:

    Warning: resolving _my_fun at 24 by linking to _my_fun

But when I ran the executable, the system crashed at the point that a
foreign function was called.

> Bear in mind that we'll be deprecating -fvia-C in the future, and also that you
> might want your code to work in GHCi too, which doesn't read any header files
> when compiling foreign imports.
>
I am currently developing on a windows xp machine. After a week of
fighting with FFI, I feel forced to conclude that FFI barely works
with GHC (and seems to require -fvia-C) and doesn't work at all with
GHCi (I think there is an unresolved bug about this). Am I wrong about
the state of affairs for windows?

thanks,
  Jeff