[Haskell-cafe] Multiple instancing of functions with FFI

[Lewis-Sandy, Darrell]

I am having trouble exporting multiple instances of a polymorphic function
similar to the example in the "Haskell 98 Foreign Function Interface 1.0
addendum" (page 6).  My specific code is below:

-----------------------begin test.hs---------------------------------

>module Test() where

 

>import Foreign

>import Foreign.C

 

>foreign export stdcall "addByte" (+):: Int8->Int8->Int8

>foreign export stdcall "addInt"  (+):: Int16->Int16->Int16

>foreign export stdcall "addLong" (+):: Int32->Int32->Int32

-----------------------end test.hs---------------------------------

 

This somewhat contrived example should export three foreign implementations
of integer addition (one for each of 8, 16 and 32 byte integers).   I am
compiling to a Win 32 DLL with GHC 6.61 using the following set of commands:

 

--------------------------------------------------------

ghc -c adder.hs -fglasgow-exts -ffi

ghc -c dllMain.c

ghc -static --mk-dll -optdll--def=test.def -o test.dll test.o test_stub.o
dllMain.o

--------------------------------------------------------

 

where dllMain.c declares my entry point for the DLL, and is as follows

--------------------begin dllMain.c------------------------------------

#include <windows.h>

#include <Rts.h>

 

extern void __stginit_Adder(void);

 

static char* args[] = { "ghcDll", NULL };

 

BOOL STDCALL DllMain ( HANDLE hModule, DWORD reason, void* reserved )

{

  if (reason == DLL_PROCESS_ATTACH) {

      startupHaskell(1, args, __stginit_Adder);

      return TRUE;

  }

 

  if (reason == DLL_PROCESS_DETACH) {

        shutdownHaskell();

        return TRUE;

  }

 

 

  return TRUE;

}

----------------------------end dllMain.c----------------------------

 

and I have declared the exported function names explicitly in test.def: 

---------------------------begin test.def-----------------------------

EXPORTS

   addByte

   addInt

   addLong

----------------------------end test.def----------------------------

 

Upon compilation, I receive a long list of errors including things like
"error:redefinition of 'stginit_export_Test_zdfzp' was here", etc.  Any help
would be appreciated.

 

Darrell

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