Re: light userdata (Was: Fastest way to transfer data from C to Lua ?)

[Roberto Ierusalimschy <roberto@...>]

> > I think nobody should give lightuserdata to a script just like a variable.
> 
> I'm not sure what you mean exactly here, but giving userdata, light or
> not, to a Lua script is totally harmless because userdata has no instrinsic
> operations, except for equality test. The real issue is sending userdata
> to the host: C code must ensure the validity of the corresponding pointer.

I guess what he means is that it is not trivial to ensure the validity
of a light userdata. So, more often than not, when a lightuserdata
goes to a script, it ends up being used by its corresponding C library
without a proper validation.

-- Roberto