Re: GC of external resources

[Diego Nehab <diego@...>]

Hi,

> > I forget what is the standard solution to make Lua's GC
> > aware of the external cost of a "userdata" value. Sometimes
> > you have a userdata representing, say, an image. But the
> > image itself takes more room than the userdata because it
> > was allocated outside of Lua (sometimes you can't change
> > that). So Lua might not feel like collecting the userdata
> > eventhough it represents a lot of memory and is not
> > referenced anymore.
> >
> > Can anyone refresh my memory?
>
> __gc

__gc will only be executed when the garbage collector feels
like it. This decision is based on how much memory 
the userdata itself takes (a few bytes). However, this userdata 
might be just a boxed pointer, pointing to a big hunk of external
memory (say, a few megabytes).

[]s,
Diego.