Re: Strane linker errors when exporting DLL that uses ADO

From:

"Giovanni Dicanio" <giovanni.dicanio@invalid.com>

Newsgroups:

microsoft.public.vc.language

Date:

Thu, 24 Apr 2008 12:07:45 +0200

Message-ID:

<er5PfMfpIHA.4112@TK2MSFTNGP03.phx.gbl>

"Ulrich Eckhardt" <eckhardt@satorlaser.com> ha scritto nel messaggio
news:e2t5e5-lcp.ln1@satorlaser.homedns.org...

class __declspec(dllexport) A
{
//All kinds of stuff
virtual method( _RecordsetPtr rs );
};

Well, that will fail if you include above code there, because that code
would tell the compiler that you want to export both A and B from that
other DLL. You need to switch to __declspec(dllimport) for code that
actually should import stuff from a DLL.

I thought that the OP's code was just a sample code, not the real code.

In fact, he wrote:

<quote>
The weird thing is that if I change the method
to not be virtual, or if I change the parameter to not be a
RecordsetPtr, the code links successfully.
</quote>

so my understanding was that the OP had correctly implemented the
__declspec(dllexport/import) mechanism, e.g. using the classical
preprocessor conditional stuff:

// In MyDll.h

#ifndef MYDLL
#define MYDLL __declspec(dllimport)
#endif

class MYDLL A
{
....
};

and:

// In MyDll.cpp
#define MYDLL __declspec(dllexport)
#include "MyDll.h"

....

Giovanni