[fpc-pascal] stdcall vs. cdecl: another "using a FPC-generated .dll with Microsoft Visual C++" question

[Seth Grover]

I appreciated Henry's comment regarding my last question (generating a
.lib file from a FPC-generated for linking with VC++). I ended up
using implib (http://implib.sourceforge.net) to generate the .def file
with dll2def.exe and then fasm.exe to create the .lib file from that,
and VC++ seems to link fine against it.

My fight is with calling conventions and exported names. I've read the
programmers guide chapters 6, 7, and 12, and got a lot of useful
information out if it. I'm trying now to get a grasp of how different
calling conventions work, what different compilers generate what name
decorations with the different calling conventions, what compilers
require when linking against them, etc.

I've got a little test library with two functions:

function stdcallSquare(value : cint) : cint; stdcall;
function cdeclSquare(value : cint) : cint; cdecl;

And I'm trying to use them in a Visual C++ project. In my .cpp file, I have:

extern "C" {
	int __declspec(dllimport) __cdecl cdeclSquare(int value);
	int __declspec(dllimport) __stdcall stdcallSquare(int value);
}

In the "exports" section of my FPC library, I can simply export
cdeclSquare without modifying the name it's exported as, and VC++
finds and links against and calls it just great.

If I try to export sdtcallSquare without modifying the name it's
exported as, VC++ complains with "1>testdll.obj : error LNK2019:
unresolved external symbol __imp__stdcallSquare at 4 referenced in
function _wmain".

If I put "stdcallSquare name 'stdcallSquare at 4'" in my exports section,
then VC++ seems to be happy with it and it links and calls the routine
Ok.

So my question is, is there a way to have FPC automatically generate
the decoration VC++ is looking for? Or does anyone know of a way to
make VC++ find and link stdcall functions without the decorations?

I know I could just use cdecl and forget about stdcall altogether, but
I'd like to learn how to do it with stdcall but I'm just curious to
see if there's a way to get stdcall to work without having to manually
put the decorations on the exported names myself.

Thanks,

-SG

--
This email is fiction. Any resemblance to actual events
or persons living or dead is purely coincidental.

Seth Grover
sethdgrover[at]gmail[dot]com