Hi,
"I grumble about VFP because it's still not easy to define custom data structures or callback functions ... but that's a topic for another day."
you may have a look @
www.vfp2c.comit's an interop library for VFP/C development.
It contains C struct/union converter. And there's also a function CREATECALLBACKFUNC in the FLL library which can JIT assemble C callback functions.
Regards
Christian