On 15 September 2004 00:33, Roberto Zunino wrote:

However, compiling with

ghc -prof Main.hs test.c -#include test.h

or s/-prof/-fvia-C/, works fine, provided test.h contains the correct function prototypes.

------ test.h long long myInt64(void); double myDouble(void); ------

AFAICS, it seems as the asm code generator knows about the Haskell types and therefore knows how to fetch the bits correctly, while the via-C code generator simply uses the C function calls (without prototypes), so functions return types are defaulted to int.

Also, you can try adding -Wall and see if the C compiler warns about this (mine does).

The GHC user's guide (section 8.2.2) is also insightful. It seems that using C headers is pretty much required, or, as the guide itself says, "You're crazy not to do it". ;-)

This is correct. You should get a warning from the C compiler even without -Wall, because we turn on -Wimplicit to catch exactly these problems. Cheers, Simon