Re: Exit one Lua state from a (C) API function

[Sean Conner <sean@...>]

It was thus said that the Great bel once stated:
> I need to create a Lua API function to close/exit a Lua state from a Lua
> script.
> While “os.exit” will exit the entire host application, I just want to
> “exit” one (of multiple) Lua states and return to the “lua_pcall” in C,
> while the application (and the other states) keep running.
> 
> Something like this:
> 
> my_C_function()
>     lua_newstate
>     lua_pcall -->
>         Some Lua code
>         Lua pcall -->
>             more Lua code
>             call "state exit" function -------------|
>             Lua code that should not be executed    |
>         More Lua code that should not be executed   |
>     [continue here]  <------------------------------|
>     lua_close

  It's hard to follow your code above.  So let's add some state to
it---namely some Lua states:

	my_C_function(L1)
		L2 = lua_newstate()
		lua_pcall(L? .. what lua state goes here?)

		-- skip rest of code above because of lack of
		-- information about which state we're in where
		
  There also may be some confusion.  There are a few functions that return a
new Lua state:

	lua_State *lua_newstate(lua_Alloc,void *);
	lua_State *luaL_newstate(void);
	lua_State *lua_tothread(lua_State *,int);
	lua_State *lua_newthread(lua_State *);

  The first two create a new Lua state, without reference to any other
state.  The next one, lua_tothread() is like lua_tointeger() or
lua_tostring(), returning the value from a Lua stack index.  The last one at
confused me when I was first starting out.  It returns a new Lua state L2
that is related to the given Lua state L---they both share the same global
space.  Is this perhaps what the issue is?

  Even if you are creating a separate Lua state (separate from the calling
state), then your question, or rather, example, becomes:

	lua_pcall[1]
		-- code code code
		lua_pcall[2]
			-- code code code
			state_exit() -- returns to [1], skips [2]
		end
	-- resumed here

  So aside from the Lua state weirdness, you are trying to, for lack of a
better term, skip back to the outermost pcall?

  -spc