Jack,

>I found your "Spy-In" VFP/C++ app useful as a learning tool for incorporating C++ DLL's in my own projects. Although I am not very proficient in C at this point, I would like to learn more about it to provide compiled modules in future apps.

Great! that's why I put it up there.

>How do you come to a decision to develop a DLL as opposed to a pure VFP solution? If I am looking at developing C++ classes to handle math intensive routines, could I actually be making things more complicated than I have to? The type of routines would handle premium and claims processing in the area of medical/dental insurance...

Well when VFP is too slow you use something faster *g* The project didn't turn out to be how can I build a C++ dll, I just wanted to browse the string contents of huge DLLs on my system to see if I could get rid of them. The VFP code to process strings of more than 100K or so was too painfully slow. I'd done a lot of C before Xbase and knew the C code would be much faster in there so used that as an excuse to see how to use a C dll.

It's not really all that hard to do once you've got the mechanics figured out. But I wouldn't bother unless you find some chunk of VFP interpretted code is a significant bottleneck. There is some overhead involved with calling a DLL though, but not near as much as was involved with the old FLLs.