Hi all,

I need to call an Haskell module from Excel and as an exercise I started to play with the example given in GHC documentation: http://www.haskell.org/ghc/dist/current/docs/users_guide/win32-dlls.html

I could build the DLL without problem but encountered a problem when using it. I created an Excel document using the dll. If I open the Excel document, do something that will trigger a function call in the DLL, then Excel will crash on Exit. On the opposite if I open the same document and changes cells not related to the function the program closes properly. I does not crash directly on the function call but later, just when I close Excel.

As it crashes when closing Excel I suspect something is wrong when unloading the dll. I modified the dllMain.c code to handle the DLL_PROCESS_DETACH event but it doesn't solve the problem.

} else if (reason == DLL_PROCESS_DETACH) {
shutdownHaskell();
return TRUE;
}

I attached the code to this e-mail. I built the dll this way:

ghc -fglasgow-exts -c adder.hs
ghc -c dllMain.c
ghc -shared -o adder.dll adder.o adder_stub.o dllMain.o

Any idea on what could go wrong? Another event to handle?

Thanks,

Olivier.