SevenThunders wrote:
SevenThunders wrote:
I am having some difficulty with creating a dynamic link library using GHC on windows XP.
I need to report some additional strange DLL behavior with ghc.exe unfortunately.
Although I solved my linking problems and was able to create a .dll and a MS VC .lib file using a .def file. I get a nasty run time error when my program exits.
Here is a snippet of the Haskell code: module ExternLib where
... import Foreign.C.String import Foreign.Ptr import Foreign.C.Types (CInt, CDouble ) import Foreign.Marshal.Array import Foreign.Storable
foreign export stdcall initNetChan :: CString -> Ptr CInt -> IO ()
-- | initialize network parameters and return an integer array containing -- indices to the uplink channel, downlink channel initNetChan :: CString -> Ptr CInt -> IO() initNetChan simstring cptr = do
-- some processing ...
let hup = mkCInt $ hupchan netop let hdn = mkCInt $ hdnchan netop print $ "hup = " ++ (show hup) print $ "hdn = " ++ (show hdn) -- write results to the output array pokeElemOff cptr 0 hup pokeElemOff cptr 1 hdn peekElemOff cptr 0 >>= print
Here is the C code that calls it, (test.c)
#include
extern void initNetChan(char *str, int *iout) ;
int zout[64] ;
int main(int argc, char *argv[]) { printf("Starting initNetChan\n") ; initNetChan("SimPrams.in", zout) ; printf("Done initNetChan. out: %p\n", zout) ; printf("out[0] = %d out[1] = %d\n", zout[0], zout[1]) ; printf("Done") ; return(1) ; }
The dll itself uses this template taken from the GHC manual on DLLs #include
#include extern void __stginit_ExternLib(void);
static char* args[] = { "ghcDll", NULL }; /* N.B. argv arrays must end with NULL */ BOOL STDCALL DllMain ( HANDLE hModule , DWORD reason , void* reserved ) { if (reason == DLL_PROCESS_ATTACH) { /* By now, the RTS DLL should have been hoisted in, but we need to start it up. */ startupHaskell(1, args, __stginit_ExternLib); return TRUE; } return TRUE; }
I link test.c to my dll via a call cl.exe test.c netsim.lib
Running test.exe yields Starting initNetChan "hup = 26" "hdn = 30" 26 Done initNetChan. out: 00408960 out[0] = 26 out[1] = 30 Done D:\Projects\BRPhoenix\NetworkSim\FastSim>test.exe Starting initNetChan "hup = 26" "hdn = 30" 26 Done initNetChan. out: 00408960 out[0] = 26 out[1] = 30 Done
which is correct, but then the code crashes with a run time error. It is an unhandled exception: access violation. Is it possible that the Haskell code needs to do some kind of finalization process before terminating? I haven't seen the documentation for it yet. Hopefully it's just something stupid I've done, but again I am baffled.
Well I'm batting 1000 today. It was my dumb fault again. In case this helps someone else, I forgot to use the --stdcall prefix to the function declaration. Thus my stack was trashed. I needed to use a declaration something like __declspec(dllimport) void __stdcall initNetChan(HsPtr a1, HsPtr a2); -- View this message in context: http://www.nabble.com/Creating-DLLs-with-GHC-tf2342692.html#a6539496 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.