Re: caching userdata pointers, lua_pushuserdata?

[Kriss <Kriss@...>]

Mark Hamburg wrote:

> The safe way to do this is to maintain a weak table mapping the userdata
> pointers as light userdata to the full userdata objects. Pushing then
> becomes something like the following:
>
>    lua_pushlightuserdata( L, &myUDMapKey );
>    lua_gettable( L, LUA_REGISTRYINDEX );
>    lua_pushlightuserdata( L, theUserData );
>    lua_gettable( L, -2 );
>    lua_remove( L, -2 );
>
> (I used a light userdata rather than an integer to key the registry because
> it's easier to guarantee unique.)
>  
Thanx, that gave me a better idea for how to handle things in my case.

I can key my table with light userdata of the same address as the real 
user data. Easy to lookup from the c side, guaranteed unique keys. A 
simple function to return a light userdata with the same address of any 
given userdata will keep it accessible from the lua side when all I have 
is a userdata to hand.

Much simpler.

--

Kriss

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