Re: Threads in CHECK/INIT blocks leak scalars

On Fri, Mar 16, 2007 at 08:22:59AM -0700, Jerry D. Hedden wrote:
> Using threads inside CHECK or INIT blocks causes leaked scalars:
> 
> > perl -Mthreads -e 'CHECK { threads->create(sub {})->join; }'
> Scalars leaked: 1
> 
> What is the scalar that is leaking?

It's the cloned copy of the CHECK CV. It's cloned because the anon sub has
a weak reference to it, but has a refcnt of zero due to that weak
reference. It also exists on the savestack (having just been shifted off
PL_checkav in Perl_call_list), but that's not cloned.

> Can this be fixed?

Dunno. There was another problem with items only on the savestack leaking,
and Nicholas suggested a fix that I need to get me head round one day.

-- 
The optimist believes that he lives in the best of all possible worlds.
As does the pessimist.

• Threads in CHECK/INIT blocks leak scalars by Jerry D. Hedden
• Re: Threads in CHECK/INIT blocks leak scalars by Dave Mitchell