Re: __gc visible to lua code...

[Luiz Henrique de Figueiredo <lhf@...>]

> so any __gc metamethod in C must typecheck the argument.

Yes. And in the case of boxed pointers, invalidate it somehow.
That's what the io lib does. (But I'm afraid not all my libraries do it.)
Bottom line: you have to write C binding code carefully.
--lhf