Re: using finalizers

[Tomas Hlavaty]

On Sat 01 Jan 2022 at 15:55, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>>> My original issue did not run the finalizer because of a bug in my use
>>> of letrec.  Unless there is a good way to actually trigger the
>>> finalizer, there is no good way to test such code paths.  Or shall the
>>> programmers just hope for the best?
>
> Calling `garbage-collect` should usually work well enough for tests

good, thanks

> (tho this may have to be tweaked if/when we get a fancier GC), tho
> there's always the risk that some bitpattern somewhere inside the stack
> happens to look like a pointer to your finalizer (or an object that
> transitively references it), so no I don't know of a way to *reliably*
> get a finalizer to run.
>
> You can minimize the risk of a bitpattern getting in the way by trying
> to trigger a GC at a point where the C stack is as small as possible,
> but it still can't rule out the problem completely.

What does "trigger a GC at a point where the C stack is as small as
possible" mean?  Does it mean trigger gc explicitly from top level?