Hi, you have to peek the pointed value. Something like: hklFactoryGetAll :: IO [HklFactory] hklFactoryGetAll = alloca $ \ptrn -> do factories <- c_hkl_factory_get_all ptrn n <- peek ptrn peekArray n factories 2015-11-08 10:55 GMT+01:00 PICCA Frederic-Emmanuel < frederic-emmanuel.picca@synchrotron-soleil.fr>:
Hello,
Here the signature of one of my C function
-- hkl.h --
typedef struct _HklFactory HklFactory;
HKLAPI HklFactory **hkl_factory_get_all(size_t *n) HKL_ARG_NONNULL(1);
HKLAPI HklFactory *hkl_factory_get_by_name(const char *name, GError **error) HKL_ARG_NONNULL(1) HKL_WARN_UNUSED_RESULT;
HKLAPI const char *hkl_factory_name_get(const HklFactory *self) HKL_ARG_NONNULL(1);
HKLAPI HklGeometry *hkl_factory_create_new_geometry(const HklFactory *self) HKL_ARG_NONNULL(1);
HKLAPI HklEngineList *hkl_factory_create_new_engine_list(const HklFactory *self) HKL_ARG_NONNULL(1);
I will focuss for now only the get_all method. As you can see even for the C client of my API HklFactory is an opac struct This get_all method return an array of (HklFactory *) and get the size of the array via the n parameter.
So I am trying to use this API from haskell with the foreign system and return a [HklFactory]
import Foreign (Ptr, peek) import Foreign.Marshal.Alloc (alloca) import Foreign.Marshal.Array (peekArray)
data HklFactory
foreign import ccall safe "hkl.h hkl_factory_get_all" c_hkl_factory_get_all :: Ptr Int -> IO (Ptr HklFactory)
hklFactoryGetAll :: IO [HklFactory] hklFactoryGetAll = alloca $ \n -> do factories <- c_hkl_factory_get_all n peekArray n factories
but indeed it doesn not work, peekArray complain that n is Ptr Int instead of Int.
what should I do in order to get my array of HklFactory
thanks for your help.
Frederic _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners