Hanging visual foxpro app - can I use userdump/windbg?

I have a visual foxpro 6 applica开发者_如何学Pythontion which is hanging (100% CPU). Process explorer etc don't indicate any activity, so it is obviously in some kind of loop.

For a .net or C app I would take a dump of the process when it is hung, and identify which method is causing the problem. Can a similar technique be done using foxpro, or any advice on how to identify the method involved?

We have complete access to the sourcecode, and can rebuild it. But we are unable to recreate the problem at our facility - we only see this happen occasionally at a single customer.

I'm presuming here that you have access to the source code. Can you replicate the issue while tracing the code in the VFP debugger?

Unfortunately, userdump and windbg cannot be used for debugging Foxpro source. You can debug Visual Foxpro programs by interactively running the source within the IDE. The built in debugger will allow you to step through code, and see what is happening - if you can duplicate it in a test/dev environment. Once in compiled form, debugging becomes very difficult if not impossible.

Since this is only happening onsite, the best option is to modify the source to generate a debug log - basically writing to a file (STRTOFILE()) whenever key events happen. I've had the misfortune of this kind of problem before and this was the best viable option, at the time.