Manage VB6 callback problem with external C DLL
Posted on 2010-11-22
Question: Hi experts!
I have a Vb6 application which call C DLL via _stdcall. I manage to rule this external hardware no matter of some limits of VB6, with exception of callback. Callback function do not works and I need to find a solution. Problem with callback function is that in Vb6 IDE it works fine, but in .exe file don’t work and make great crash (somethink even with blue screen :-) )
If I understand correct, problem is because the DLL calls these callback functions from other thread (for safety reason) and in this case VB6 can’t manage. More clearly, I get callback function OK even in exe file, but if I try to read a parameters of this callback it crash. I need these parameters!
So I consider to create a application in VC C++ which cover these function and to use it in VB6. Question is – what type of application I need to create in C ++ ? Can it be OCX, in which thread are executed OCX ? Or it should be DLL? But this callback is best to be return like events, I think this can be done only with ActiveX.