> The issues can't be separated -- what is passed to an external
> procedure facility must be sufficient for a procedure to do it's work,

Now I think I understand our problem here - the key phrase is "what is
passed".

It is correct, that you, Jim, expect the engine to pass the callbacks
(whatever they are - isc_XXX, jrd8_XXX or InternalConnection instance)
into the open(...) method of the external procedure?

If that is your expectation, then it is different to what we were
thinking about - we were thinking about getting the callbacks from the
environment when and if needed (think of TLV, for example). In this
case we can concentrate on the parameter passing first without
discussing the callbacks. If that is wrong from your POV, please
explain why.

Roman