I built quite a big library and turned it into a package. It works fine if use ghc -package gtk2 Blah.hs to compile things. But when I convert all the libraries to object files as described in the documentation, GHCi refuses to load the whole machinery:
~/source/mogul/fpDemo:$ ghci -package gtk2 Arabic.hs ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 5.02.2, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help.
Loading package std ... linking ... done. Loading package lang ... linking ... done. Loading package gtk2 ...
GHCi runtime linker: fatal error: I found a duplicate definition for symbol gcc2_compiled. whilst processing object file /home/as49/local/lib/gtk2hs/gtk2hs.o
I think this is due to a bug in GHCi's linker, which has been fixed post 5.02.2. I tripped over it recently while trying to use Gtk+HS in GHCi on my RedHat 7.2 box. There are two bugs tickled by gcc 2.96: our linker wasn't dealing with sections with names other than the standard ones (.text, .data, .rodata) properly, and there was also some infelicities in the local-symbol handling (Julian S. can tell you more). The workaround I used is to compile up any .c files in your package *without* -O, and without -g if you were also using that. Cheers, Simon