Thanks Mike, that simple test makes it clear. Nils On Tue, Nov 19, 2013 at 12:55 PM, Mike Pall <mike-1311@xxxxxxxxxx> wrote: [..] > A simple test is to ask: where has the 'C api' part in your call > stack gotten its lua_State pointer? The FFI deliberately doesn't > provide one -- don't pass a lua_State behind its back. [..]