Re: [perl #24138] GLOB_ERROR shared across threads

According to Michael J.Pomraning :
> > No, GLOB_ERROR is actually stored in a thread specific place.
> 
> Hmm -- could you try the following example?  For me, Thread #1 changes
> the return value of GLOB_ERROR() out from under (the older) Thread #0:

I can see that. I don't know why it behaves that way ; I just
hope this doesn't indicate a bug in the code generated by
ExtUtils::Constant or in MY_CTX.

>   $ cat glob2.pl
>   use threads;
>   use File::Glob qw|:glob|;
>   use strict;
> 
>   sub globerr() {
>     print "Thread ", threads->tid, " GLOB_ERROR():",
>           GLOB_ERROR(), "\n";
>   }
>   
>   sub e($) {
>     my $g = shift;
>     print "calling glob()\n";
>     bsd_glob($g);
>     globerr();
>   }
> 
>   e("/tmp");
>   threads->create(\&e, '/root/eacces*')->join;
>   globerr()
> 
>   $ perl glob2.pl 
>   Thread 0 calling glob()
>   Thread 0 GLOB_ERROR():0
>   Thread 1 calling glob()
>   Thread 1 GLOB_ERROR():-2
>   Thread 0 GLOB_ERROR():-2
> 
> Same config as before.  It surely looks to me like the value being
> returned is shared across threads:  TID 0 glob()s, checks error, spawns
> TID 1 to do the same; after TID 1 completes, TID 0 checks error again,
> and (voila) it has changed.
> 
> I think I understand what the XS is trying to do, I just don't see that
> behavior.
> 
> > I don't know if it's possible to register code to be called at
> > interpreter clone time. It so, we could make it reset GLOB_ERROR.
> 
> ISTM that storing the C return value of glob() in an ordinary, unshared
> package lexical, and having GLOB_ERROR() fetch that, would have the
> desired effect.

• [perl #24138] GLOB_ERROR shared across threads by perlbug-followup
• Re: [perl #24138] GLOB_ERROR shared across threads by Rafael Garcia-Suarez
• Re: [perl #24138] GLOB_ERROR shared across threads by Rafael Garcia-Suarez