Matthew Donadio wrote:
I am just starting to experiment with FFI, and am running into a problem. I was to create an FFI to the lgamma(3) found in many of the newer libm implementations. My code follows the sig.
The lgamma function works. The gamma function core dumps (I am using ghc 5.04.3) on me. gdb reports a SIGSEGV in signgam(), but I'm not sure why. I believe that I need to use the monad because signgam is only valid after lgamma returns.
Does anyone have an idea what I am doing wrong?
Thanks.
-- Matthew Donadio
module Gamma (gamma, lgamma) where
import System.IO.Unsafe
foreign import ccall "math.h lgamma" lgammaC :: Double -> IO Double foreign import ccall "math.h signgam" signgamC :: IO Int
signgam is an "int" variable, but this assumes that it is a function
of type "int signgam(void)".
Write a C wrapper "int get_signgam(void) { return signgam; }" and
import that.
--
Glynn Clements