How do you debug an 'Unhandled Exception'?

I have seven class modules that are almost identical except the code that generates the SQL Statement and the code that takes the recordset and stores the information into the object.

My development environment is Windows NT 4.0 SP5 running VB 6 SP3 using ADO 2.1.

The problem I'm having is in one, and ONLY one class module. I get this error message :

'The instruction at "0x0fa91757" referenced memory at "0x00000004". The memory could not be "read".'

I click on CANCEL to debug the application and it transfers me to the VC++ disassembly screen. In the code pane, this line has the yellow arrow beside it:

77F7629C CC int 3

There is also another message box that reads:

'Unhandled exception in VB6.EXE (VBA6.DLL) : 0xC0000005 : Access Violation'

When I click on OK the code pane now reads:

0FA91757 8B 40 04 mov eax, dword ptr [eax+4]

The value of EAX = 00000000
The value of [EAX+4] = ????????

I added a watch to '0FA91757' and it has the value of :

CXX0013 : Error : Missing Operator.


I get this error about 85% of the time, if I run the application in the IDE or from a compile EXE. I don't get this error message if I step through the code in the class module line by line.

I am able to narrow down which line of code is causing it within 5 lines of code, but the problem is that the error alternates between two different places within the class module, both dealing with opening a recordset with ADO. I couldn't find anything in the Microsoft knowledge base and was hoping that someone would be able to give me some insight as to why this is happening and how to resolve the issue.

Matthew Brook

sounds like you have run into a bug (in VB6? in ADO 2.1?).
Try service pack 4 for Visual Studio. It has just been released a few days ago.
Try ADO 2.5.

Thanks for the tip. I downloaded and installed both ADO 2.5 and VS SP4.

I noticed a speed improvement overall for my application, but I still have the same problem. This time the error is coming up at instruction "0x0fa91c19". I think the problem may have something to do with asynchronous fetching of the recordset. I'll continue working on the problem and post any findings I get.

If the problem is finally resolved, does Microsoft need to be notified of this problem?

Thanks

Matthew Brook

>If the problem is finally resolved, does Microsoft need to be notified of this problem?

:-)
I think, they won't go out of business if you don't tell them.
But, telling them is certainly a good idea.