Question about packages and GHCi

Isaac Jones ijones at
Tue Feb 1 22:16:39 EST 2005

Martin Erwig <erwig at> writes:

> I apologize if this is the wrong mailing list to turn to,
> but I would be grateful for any help with two problems
> I have when trying to add a package to GHCi. (I wasn't able
> to find sufficient information in the documentation for packages
> (1) When I try to add a package to ghc, I receive the
> error message that a GHCi lib fil cannot be found.
>    > ghc-pkg -u -i fgl.pkg
>    Reading package info from "fgl.pkg"done.
>    Expanding embedded variables... done.
>    warning: can't find GHCi lib `HSfgl.o'
>    Saving old package config file... done.
>    Writing new package config file... done.

Try ghc-pkg -u -i -g fgl.pkg

>    GHCi runtime linker: fatal error: I found a duplicate definition
> for symbol
>       __module_registered
>    whilst processing object file
>       /usr/local/lib/ghc-6.2/HSfgl.o
>    This could be caused by:
>       * Loading two different object files which export the same symbol
>       * Specifying the same object file twice on the GHCi command line
>       * An incorrect `package.conf' entry, causing some object to be
>         loaded twice.
>    GHCi cannot safely continue in this situation.  Exiting now.  Sorry.

I don't know about this one.



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