Christiaan suggested that I try cabal installing "--disable-library-vanilla" which I combined with --enable-shared. It almost works. It causes ghc to only create the dynamic libraries. However, ghc-pkg register fails with the error: 

/usr/local/bin/ghc-pkg update - --global --user --package-db=dist/package.conf.inplace

cabal: TestLib-0.1.0.0: cannot find libHSTestLib-0.1.0.0.a on library path

(use --force to override)

Failed to install TestLib-0.1.0.0

It seems that ghc-pkg thinks that we must have the .a files to register the package. (I scanned the ghc-pkg source and it looks like checkHSLib is where this check happens.)

So, is the check in ghc-pkg really correct? I.e. the package would be unusable without the .a file? Or would this be OK, so we really should change ghc-pkg? 

-Andi

On Fri, Oct 4, 2013 at 6:35 PM, Andreas Voellmy <andreas.voellmy@gmail.com> wrote:

Hi all, 

Is it possible to have a Haskell package that only includes a dynamic library and .dyn_hi files? I.e. it would omit the .o and .a files? I tried building a library using cabal and --enable-shared. It still includes the .o and .a files. 

Will builds with "-dynamic" and loading modules in ghci work correctly if I just delete the .o and .a files?  I did a few experiments and it seems to work OK, although it seems that things break if I delete the .hi files, even though I'd expect only the .dyn_hi files would be used. 

-Andi