Re: Application crash on calling a COM method

From:

Scot T Brennecke <ScotB@Spamhater.MVPs.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Tue, 04 Aug 2009 02:37:37 -0500

Message-ID:

<uDmgxZNFKHA.1252@TK2MSFTNGP04.phx.gbl>

Gopal wrote:

At the outset, apologies for not providing the exact code. I cannot share the
code snippets here.

I have an MFC application which uses a normal win32 helper DLL. This DLL
inturn #imports a COM server (out of process EXE) which has a an interface
derived from IDispatch. Now all I do in the win32 dll is
- CoCreateInstance
- Addref
- Intf->function()
- Release

The above code worked perfectly fine when I was compiling it in VC6. The
moment I moved the MFC app and the win32 to VS2005, my application crashes
randomly after the function is called. This may happen at the first instance,
or sometime it takes 10-15 tries to get it to crash.

I suspect some kind of memory corruption because of marshalling, but haven't
quite been able to catch the culprit.

Any pointers would be of immense help.

regards,
~GOpal

So, tell us what is involved in the function call; are you passing any objects in either direction? Where does your app crash;
i.e., what code is executing when the crash occurs? Is it an access violation? Are you able to make it happen with a debugger (VS,
WinDbg, ADPlus, DebugDiag, etc.) attached?