Re: MFC Regular DLL and static/global objects
On 9 Jun 2006 08:00:38 -0700, "PriyKo" <K.Lakshmipriya@gmail.com> wrote:
From the article below-
http://www.msdn.net/msdnmag/issues/05/02/CATWork/default.aspx
For an MFC dll, it appears that _CRT_INIT calls the constructors for
the static objects and DllMain gets called later by _DllMainCRTStartup.
Since I am using MFC, all the above gets handled by the framework.
Regardless of what the DLL entry point is called, all that is done in
DllMain context.
My problem is that my dll has around 4 support classes which the
exported functions access. These support classes share a single global
object -
The global object is an instance of a C++ class that uses MFC and WMI.
When the object gets instantiated, the constructor initializes COM and
connects to WMI. In the destructor COM uninitialization and other
cleanup is handled. The other functions in the class use WMI to get/set
info.
Right, those are things you shouldn't be doing inside a DLL global ctor or
dtor, or more generally, inside DllMain.
The problem I am facing is, when it is a normal unmanaged dll and I
call it from an unmanaged app, the ConnectServer() call to connect to
WMI hangs (sorry, its not an exception as I mentioned initially).
I am using Visual Studio 2005. If I create a /NOENTRY dll, the global
objects dont get initialized and CRT libraries dont get linked in.
Could you explain a little more about the initialization functions you
are talking about (I am not clear where to create the global object)
You need to avoid relying on the construction/destruction of a DLL global
for these things. You need to initialize your DLL after all DLL
initialization has completed. You can do this from an EXE global or inside
main.
--
Doug Harrison
Visual C++ MVP