Re: lua_close() locks but never unlocks... ?

On the other hand, there is nothing stopping you from creating a
binding to an arbitrary shared structure, which the various threads
could access through a userdata. That structure would need its own
lock, of course. You could make that look really a lot like the
userdata were a native table. So that way you could run multiple Lua
universes without the lua_lock() mechanism, as long as you ensured that
each Lua universe was only active in one thread (at a time).