Re: The purpose of LUA_ENVIRONINDEX pseudo index

[Nick Gammon <nick@...>]

On 09/09/2006, at 6:36 AM, Jose Luis Hidalgo wrote:

>   I'm not sure if what I'm going to say it's correct, but from the
> manual "The environment of the running C function is always at
> pseudo-index LUA_ENVIRONINDEX" I think that the lua_environindex is
> only accessible when your function gets called from lua, and not when
> you are creating a new state. For example:
>
> int test(lua_State *L) {
> 	lua_newtable(L);
> 	lua_replace(L, LUA_ENVIRONINDEX);
> 	return 0;
> }
> int main(int argc, char* argv[])
> {
> 	lua_State * L = luaL_newstate();
> 	luaL_openlibs(L);
> 	luaL_dostring(L, "print(_VERSION)"); // Lua 5.1
> 	lua_pushcfunction(L,test);
> 	lua_setglobal(L, "test");
> 	luaL_dostring(L, "test()");
>        lua_close(L);
>        return 0;
> }

I think you are partly right here. However the dostring is  
unnecessarily complicated. Try this:

lua_pushcfunction(L,test);  // the function that uses the environment  
- now on the stack
lua_call (L, 0, 0);         // run it as a Lua function


I also had crashes using LUA_ENVIRONINDEX until I called my  
initialization code this way.

- Nick