突然ながら、FFIを試してみたり…

#include "hsFFI.h"
#include <stdio.h>
void __stdcall print_hex(HsInt a)
{
 printf("%x", a);
}

foreign import stdcall "print_hex" printHex :: Int -> IO ()
main :: IO ()
main = do printHex 1234

>ghc ffi.hs ffi_c.hc -fglasgow-exts
Warning: retaining unknown function `_print_hex@4' in output from C compiler

動くんですけど、このWarningが消せない…