Re: Using Haskell library packages - linker error

[Jakub Kądziołka]

On Mon, Sep 07, 2020 at 09:50:51AM -0400, Timothy Sample wrote:
> Hi Jakub,
> 
> Jakub Kądziołka <kuba@kadziolka.net> writes:
> 
> > I am trying to set up Agda, and I have reduced it to a simpler problem:
> >
> > $ cat test.hs
> > import Numeric.IEEE
> >
> > main = return ()
> > $ genv --pure --ad-hoc ghc@8.6 ghc-ieee754 gcc-toolchain
> > % ghc test.hs
> > Linking test ...
> > ld: cannot find -lHSieee754-0.8.0-IfCS1Dp7pQVIOQRslM6kD
> > collect2: error: ld returned 1 exit status
> > `gcc' failed in phase `Linker'. (Exit code: 1)
> >
> > How can I fix this error? Am I doing something wrong, or is this a
> > packaging bug?
> 
> GHC needs a special flag to link shared libraries.  We recently starting
> building shared libraries for our Haskell packages.  The static ones are
> still being built, but they go to a separate output.  I think you can
> fix your problem in one of two ways:
> 
>     1. Pass the “-dynamic” flag to GHC (and maybe “-fPIC”);
>     2. Use “ghc-ieee754:static”.

ghc-ieee754:static doesn't seem to exist, but passing -dynamic does
indeed work. The workaround also translates to Agda, with

$ agda --ghc-flag=-dynamic --compile hello-world.agda

I'd really rather this wasn't necessary, though. I can already imagine
having to figure out how to pass this flag to agda through build systems
and editor plugins.

On a related note, shouldn't it be possible to use agda without
specifying ghc (and transitively, gcc) in your profile?

Regards,
Jakub Kądziołka

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