Re: How do I add a "local" using the c api

[Mark Hamburg <mark@...>]

On Apr 1, 2009, at 5:51 AM, Tom Miles wrote:

> I'm getting a little confused here again as well, if another state  
> were
> to call getglobal() on our first state, would it be able to see it  
> using
> this methood?

This is where the definition of globals in C v Lua gets a little bit  
complicated and others can almost certainly explain it better than I  
can. On the Lua side, the function/chunk has an environment table and  
global lookups go to that table. There needn't be any other links to  
that table so beyond code that calls getfenv, that environment isn't  
going to escape. (You can protect yourself from Lua code doing this  
through appropriate metatable construction.)

On the C side, you have the table at LUA_GLOBASINDEX and the table at  
LUA_ENVIRONINDEX. My recollection is that the former is bound to the  
Lua state and is accessible to Lua code via getfenv. The latter is  
bound to the C code that is executing. Since you don't need to adjust  
either of these to set the environment for the script chunk, there  
shouldn't be an issue of the environment escaping.

Mark