Re: void* in Lua_State for Application?

[Roberto Ierusalimschy <roberto@...>]

> On Wed, Sep 4, 2013 at 8:33 PM, Tom N Harris <telliamed@whoopdedo.org> wrote:
> > On Monday, September 02, 2013 03:14:08 PM Emil Renner Berthing wrote:
> >> +LUA_API void  (lua_setstatedata) (lua_State *L, void *sd);
> >> +LUA_API void *(lua_getstatedata) (lua_State *L);
> >
> > What's the problem with storing a lightuserdata in the registry?
> 
> Performance, mostly. That's a table lookup worth of overhead for every
> function that needs to fetch it. A C function accessing a field in the
> lua_State is substantially faster.

Did you benchmark it for any real case (that is, a case that will waste
some time doing something useful with the retrieved pointer)?

-- Roberto