Linking to Haskell code from an external program

Simon Marlow marlowsd at
Mon Nov 17 07:28:08 EST 2008

Colin Paul Adams wrote:
> Embarassing - I simply forgot to include Fib.o in the link.
> So it links now (program crashes, but I can try to sort that out).
> I'm still intereted in knowing how to automatically get the list of
> required libraries.
>>>>>> "Colin" == Colin Paul Adams <colin at> writes:
>     Colin> I am trying to call a Haskell function from an Eiffel
>     Colin> program, using C as an intermediary.
>     Colin> For starters, I compiled and ran a variation of the program
>     Colin> shown in
>     Colin>, to
>     Colin> make sure I had the C-code right.
>     Colin> I then attempted to move it into Eiffel. I can compile the
>     Colin> C code OK, but I'm running into problems with linking.
>     Colin> I solved most of the problems by adding the -v flag to the
>     Colin> call to ghc which I used to link the original (haskell + c
>     Colin> only) program, and cut-and-paste the linker options from
>     Colin> their into the Eiffel configuration file. This isn't really
>     Colin> satisfactory - I would like some automatic way to determine
>     Colin> what the flags should be.

The only other way I can think of is to construct the arguments yourself by 
querying the package database, e.g. "ghc-pkg field ld-options rts", but 
you'll have to combine the information from several different fields of the 
packages you use, and basically reproduce what GHC does to construct the ld 
command line.


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