How can I determine the reason for errors in CW++ function calls (specifically Create)?

[WayneS]

In my multithreaded application, I use "new" to create a new CNiKnob control. When I call Create to create the window, the return value is 0. How can I determine the cause of the error? (Note that both calls are from the same thread.)

[Chris_W1]

Wayne:

The Create method is actually inherited from CWnd, so National Instruments didn't override this function. In order to troubleshoot this further, I'd need to know more about how you are using the control. Initially I would recommend starting out simple: try creating a simple MFC application that dynamically creates controls. Once this is working, try a DLL, etc.

Knowledge Base : "How Do I Create Controls Dynamically in Visual C++ When Using Microsoft Foundation Class (MFC) without the Demo Mode Message Window? (126GIBH0)" http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/d671d44f1e5384c386256529007c3672?OpenDocument

I'm referencing a Knowledge Base entry that contains some useful information about dynamically creating ComponentWorks and Too
ls for Visual C++ controls in an MFC C++ application. One very important thing that can cause problems (though probably not this problem), is that you must include a license string if you intend to dynamically create controls. You don't have to do this if you don't create the controls at run-time. This knowledge base article contains directions on how to do that.

Good Luck,

Chris Wood
Applications Engineer
National Instruments