GHC：如何使用64位GHC构建32位DLL？ （从c ++调用函数）

Question

I'd like to build the 32-bit DLL with 64-bit GHC. And here is the minimal example.

Test.hs

{-# LANGUAGE ForeignFunctionInterface #-}
module Test where

import Foreign.C.Types

foreign export ccall c_hello :: IO()
foreign export ccall boo :: CInt

c_hello :: IO()
c_hello = do
    print "Hello!" 

init_exit.cpp

#include "Test_stub.h"
#include <C:\Program Files\Haskell Platform\8.0.1\lib\include\Rts.h>

#define DLLExport extern "C" __declspec(dllexport)

DLLExport void hello()
{
    c_hello();    
}

DLLExport int HsStart()
{
    int argc = 1;
    char* argv[] = {"ghcDLL", NULL};

    char** args = argv;
    hs_init(&argc, &args);

    printf("Haskell library has been initialized!\n");
    return 0;
}

DLLExport int HsEnd()
{
    hs_exit();

    printf("Haskell library has been finalized!\n");
    return 0;
}

And then I build the library, using the following commands:

ghc -c -O Test.hs 
ghc -c init_exit.cpp 
ghc -shared -o Test.dll Test.o init_exit.o

What flags should I pass to ghc or maybe to gcc to build the 32-bit DLL instead of 64-bit? Or maybe there is another way to do this.

Answer 1

A normal Windows 64-bit GHC build (such as the one you can download from the GHC website) is only capable of building 64-bit object files. For example, it doesn't include 32-bit versions of any of the libraries that come with GHC.

Your options are to build a Windows 64-bit to Windows 32-bit cross-compiler, or just run the normal Windows 32-bit build of GHC (probably much easier).