Re: userdata and the gc

[Adrian Sietsma <adrian_groups@...>]

Chris Marrin wrote:
 > Why not just point the userdata at a memory block that you allocate and
> then pass that to the other thread? Since you allocate it, you can be 
> sure its address will not be changed by Lua, even if the userdata 
> pointing at it moves around.

You mean use a lightuserdata.

That is my current approach, but I was contemplating using Lua-allocated 
memory if it is safe to assume constancy of userdata.

given this from Roberto :

"We have no intention of
allowing userdata addresses to change during GC. Unlike strings, which
are an internal data in Lua, the only purpose of userdata is to be used
by C code, which prefer that things stay where they are :)"

I will now happily pass full userdata to a background thread (IOCP on 
Windows, fyi).

Adrian