Question about packages and GHCi

[Donald Bruce Stewart]

simonmar:
> On 02 February 2005 01:52, Martin Erwig wrote:
> 
> > 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
> >
> http://www.haskell.org/ghc/docs/latest/html/users_guide/packages.html.)
> > 
> > 
> > (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.
> > 
> > The missing file `HSfgl.o' is located on the
> > current directory as well as in the directory
> > where all other .o and .a files for GHC are
> > kept (/usr/local/lib/ghc-6.2/).
> 
> ghc-pkg is looking in the directories specified in the library_dirs
> field in fgl.pkg.  HSfgl.o should be in one of those directories.
> 
> > (2) Maybe related to the previous problem is the
> > following. When I start "ghci -package fgl", I receive
> > the following error message:
> > 
> >    Loading package base ... linking ... done.
> >    Loading package haskell98 ... linking ... done.
> >    Loading package haskell-src ... linking ... done.
> >    Loading package fgl ...
> > 
> >    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 vaguely remembered seeing this before...  googling for 'duplicate
> __module_registered' turned up this:
> 
> http://www.haskell.org/pipermail/glasgow-haskell-users/2003-December/006
> 042.html
> 
> which indicates that perhaps you should add -x to ld when building
> HSfgl.o?

Yep, ld -x is the thing. Had a similar problem when building my own libs
recently.

-- Don