EXPORT FUNCDNAME Warning


Author: Dave
Date: 03.20.16 - 4:00pm



I use my C Dlls from VB6 and C# mostly. so I need my exports to be stdcall and unmangled in the export table.

My goto export method has been the following:
#define EXPORT comment(linker, "/EXPORT:"__FUNCTION__"="__FUNCDNAME__)
int __stdcall LastError(char* buffer, int buflen){
#pragma EXPORT
This works really nicely and there is no def file to keep in sync. The exports come out clean with just the function name and no C++ mangling or stdcall mangling. (stdcall mangling is the @8 type decoration you see on the end of functions)

For vb6 or c# this is perfect. But what if you also want to use your dll from C++ now?

The .lib file this trick produces however is unusable from C/C++ now. (At least as far as I can tell, and I spent hours playing with it.)

From a Cpp client you might use code such as the following:
#pragma comment(lib,"./../sendrecv.lib")

__declspec(dllimport) int __stdcall LastError(char* buffer, int buflen);

or

extern "C"{
     int __stdcall LastError(char* buffer, int buflen);
}
Then you will get a link error unresolved external for LastError@8 The stdcall part of the name mangling is still being used and I cant force to stop.

The #pragma EXPORT carries this change into the lib file itself, which makes it unlinkable for a C client. Looking at the binary lib file we find a naked LastError symbol.

If you want to use a C client as well, then the only thing I could do is revert to using an old style def file to remove all name mangling from the export table, while still keeping the name right in the lib file.

Had my export been cdecl without the @8 crap it is ok, but then of no use for vb6/c#.

I even tried generating a test lib with my own manual def file with the @ appended to the function names using the below command line.

lib.exe /def:test.def /out:out.lib

It linked, but then expected the import to literally be LastError@8. You can probably generate that, or latter remote it from the export table but thats ugly.

Or you have to resort to using GetprocAddress and function pointers. Annoying you cant force the import completely undecorated..






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