Re: LightUserData and metatables

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2009/10/12 Duncan Cross <duncan.cross@gmail.com>

On Mon, Oct 12, 2009 at 3:48 PM, Duncan Cross <duncan.cross@gmail.com> wrote:
> This is a simplified example of how you generally want
> to handle using light and full userdata together:

Sorry, I messed this code up a bit, let me try again:

void PushMyObject(lua_State* L, MyObject* myObject) {
 lua_pushlightuserdata(L, (void*)myObject);
 lua_gettable(L, LUA_REGISTRYINDEX);
 if (lua_isnil(L,-1)) {

  lua_pop(L,1);

   MyObject** new_wrapped_ptr = (MyObject**)lua_newuserdata(L,
          sizeof(myObject*));
   *new_wrapped_ptr = myObject;
   lua_pushlightuserdata(L, (void*)myObject);
   lua_pushvalue(L, -2);

   lua_settable(L, LUA_REGISTRYINDEX);
 }
}

-Duncan

I thank you both for your responses I now see the error in my ways and how to fix it. :)

"... do you realize that by setting the metatable of a light userdata
you are actually setting the metatable of all light userdata at once ?"
I did not realise this. oops.