>>A VFP variable has some 16 bytes descriptor block, where only the first two integers (32 bit, of course) are pointer and length. The rest describe type and few other things. Dom't ask me how much more I remember, it's very little.
>
>Yupp, IIRC struct with ev_type, ev_value and in ev_value a pointer to strings if not one of the smaller types/so described in ev_type. String pointers had to be given some Handle2Pointer treatment and sometimes memory had to be locked and unlocked - pretty certain because of reshuffling unlocked memory on garbage collection time.

The information is contained in the pro_ext.h file. It contains all of the structures and functions that are available to an FLL.