Re: Any problems expected in Multiple inheritance with template class ?

From:
"Ganga Sridhar" <gangasridhar@abosoftware.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 10 Jul 2008 20:00:18 +0530
Message-ID:
<egVe9lp4IHA.5060@TK2MSFTNGP02.phx.gbl>
Thanks this is the problem we are facing:

Platform: Visual Studio 2005, Window 2003 server,Database - MS Access
2003,Technology - OleDB

We have developed database application which uses OleDB. I have derived a
class CABIOleDBSet from CCommand which works fine as code given below
template <class TAccessor, template <typename T> class TRowset =CRowset>
class CABIOleDbSet : public CCommand<TAccessor, TRowset>

{
....
}

When I use multiple inheritance i.e derived class CABIOleDBSet from CCommand
and CTest program crashes. Class CTest have virtual function TestFunc().

class CTest
{

public:

virtual void TestFunc() {}

};

template <class TAccessor, template <typename T> class TRowset =CRowset>

class CABIOleDbSet : public CCommand<TAccessor, TRowset>, public CTest

{

....

....

}

Above example works fine if CTest class do not have any virtual function

like

class CTest

{

public:

void TestFunc() {}

};

However the application crashes when we use multiple inheritance
i.e. derived class CABIOleDBSet from CCommand and CTest and CTest have a
virtual function.

Any idea what could be the problem?

Thanks and Regards,

Ganga

"Igor Tandetnik" <itandetnik@mvps.org> wrote in message
news:e%23g0$Uc4IHA.2348@TK2MSFTNGP06.phx.gbl...

"Ganga Sridhar" <gangasridhar@abosoftware.com> wrote in message
news:uJpkwOc4IHA.3796@TK2MSFTNGP03.phx.gbl

1) Is there any known problem w.r.t multiple inheritance in the above
fashion when needing use oledb interfaces of CCommand in the derived
class CMyOleDBSet especially related to the rowsets fetched?


None that I know of. Do you encounter some problems?

2) In general is there any known issue in multiple inheriting from a
template and a simple class as specified above?


Again, none that I know of. ATL does it left and right.
--
With best wishes,
   Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925

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