Re: interacting with gc

[tomas <tomas@...>]

Hi Pierre

> For example, while binding a GUI library, a button can have an image
> attached. The image and the button are userdata type, both created in
> lua (via the C API), but the image is linked to the button also via the
> C API. so, lua has no way to know that the image cannot be freed 
> because
> linked to another object outside of its control.
I think you should create a reference to the image userdata and store it 
in the button userdata.  When the button is freed Lua will call the 
button _gc and then you'll have to release the reference to the image.

> How can I tell lua the resource is being used and then no more used
> (block from gc or ready for gc)?
Check luaL_ref and luaL_unref.

Regards,
Tomás