[Haskell-cafe] FFI for a beginner

[Jason Dagit]

I don't know how to make ghc load them without using either hsc2hs or c2hs.
I've had better experiences with hsc, but your mileage may vary.

On Apr 8, 2011 3:34 AM, "Andrew Pennebaker" <andrew.pennebaker at gmail.com>
wrote:

ncurses is proving too difficult to setup, so I'm working on a new library
called charm. The C code works by itself, but I can't compile a Haskell
wrapper for it. While the tutorials at
HaskellWiki<http://www.haskell.org/haskellwiki/FFI_complete_examples>are
helpful, they're outdated. Argh! The
docs<http://www.haskell.org/ghc/docs/latest/html/users_guide/ffi-ghc.html#glasgow-foreign-headers>say
that -#include pragmas no longer work, but fail to explain how to load
code without them. Suffice to say I have no recourse but trial and error.

GitHub: charm <https://github.com/mcandre/charm> and
hscharm<https://github.com/mcandre/hscharm>

<https://github.com/mcandre/charm>$ make
cp /usr/include/charm.c .
ghc --make -fforce-recomp -o hellocharm hellocharm.hs charm.hs charm.c
-I/usr/include -dylib-install-name /usr/lib/libcharm.dynlib
[1 of 2] Compiling Charm            ( charm.hs, charm.o )
[2 of 2] Compiling Main             ( hellocharm.hs, hellocharm.o )
Linking hellocharm ...
ld: duplicate symbol _Charm_getWidth_info in charm.o and charm.o
collect2: ld returned 1 exit status
make: *** [hellocharm] Error 1

Cheers,

Andrew Pennebaker
www.yellosoft.us

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