AddressOf Problem In VB6

[jurrinus]

I am writing a program that passes an AddressOf to a dll. The dll interfaces between my program and some attached hardware. When the hardware issues an event the AddressOf function is called. When I try to access any other function or variable the program crashes. Microsoft has stated that the cause of the crash is due to an access violation. The calling dll creates a new thread and then calls the AddressOf function ergo the access violation. Article ID Q198607 explains it. Now I have contacted the manufacturer and they say its Microsoft's problem. It use to work in VB5 but no longer in VB6. I for one think it should work in VB6 but until that comes to pass I'm stuck.

Has anyone come across this problem and solved it? I don't want to write the system in C++.

I need a response in a hurry.

Many Thanks!

Jerry

[Sam Finch]

Where is your Function, Is it Definatly Public in a standard module, also check that all your parameters are declared correctly byVal or ByRef.

[jurrinus]

Where is your Function, Is it Definatly Public in a standard module, also check that all your parameters are declared correctly byVal or ByRef.

I did everything correct. VB6 supports only Apartment threads and Microsoft has probably tightened this area up and therefor the access violation. I was told it works in VB5.

I need a workaround. For example Microsoft says put all the external calls the Callback makes in a Type Library. However, the say this is a prossible fix. I'm not sure what they mean. They also suggest compiling th eproject to P-Code which I tried with no success.

So I need to know if anyone has come across this problem and did they develop a workaround.

Basically VB6 does AddressOf but you had better not call it from another thread. So if soemone developed a dll and it uses callbacks then they cannot use threads.