[Haskell-cafe] [Haskell] Linker flags for foreign export.

Jason Dusek jason.dusek at gmail.com
Wed Mar 9 22:07:25 CET 2011

On Tue, Mar 8, 2011 at 08:23, Max Bolingbroke
<batterseapower at hotmail.com> wrote:
> On 8 March 2011 05:28, Jason Dusek <jason.dusek at gmail.com> wrote:
> >   gcc -g -Wall -O2 -fPIC -Wall -o import \
> >     -I/usr/lib/ghc-6.12.1/include/ \
> >     import.c exports.so
> In my experience, the easiest way to do this is to use gcc to build
> object files from C source files, and then specify those object files
> on the ghc command line in order to get GHC to do the linking step.
> This will deal with linking in the correct RTS and, if you specify
> appropriate -package flags, dependent packages as well.
> If you want a C main function then see user guide section at
> http://www.haskell.org/ghc/docs/latest/html/users_guide/ffi-ghc.html.

  Following your advice, I was able to get a working main,
  linking the .o's (no attempt at an SO this time) with GHC.
  However, what I was hoping to do was build an SO and that
  could be linked without GHC, for example via Postgres's
  "LANGUAGE C" functionality (load SOs and run them) or Ruby's
  DL/Import (same idea for Ruby). Requiring GHC for linking
  would really frustrate that goal :)

  Is there a tutorial I should be following? Well-Typed's blog
  post on this in the early days of shared object support seemed
  to be doing what I was doing.

Jason Dusek
Linux User #510144 | http://counter.li.org/

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