Re: Trouble joining with threads from C

[Ludovic Courtès]

Hi Andy!

Thanks for your explanations.

Andy Wingo <address@hidden> writes:

> On Wed 13 Apr 2011 23:34, address@hidden (Ludovic Courtès) writes:
>
>> After reviewing f60a7648d5926555c7760364a6fbb7dc0cf60720 (which
>> addressed the same issue), I lean towards reverting it and instead
>> applying the patch I just sent.
>>
>> The problem I see with f60a7648d5926555c7760364a6fbb7dc0cf60720 is that
>> it re-introduces a pthread_key, even when using TLS, and make things a
>> bit complex IMO.
>
> The issue is that threads in Guile are not always spawned by Guile.
> It's true that of the two cases in which Guile spawned a thread, one of
> them wasn't getting the cleanup handlers called, and your patch fixes
> that; but that ignores the case of threads that are spawned by a user's
> program.

Right, I was just focusing on Mark’s case, blissfully ignoring #32436.

> For example in the following program:
>
>     void* thread (void*)
>     {
>       scm_with_guile (do_something, NULL);
>       scm_with_guile (do_something_else, NULL);
>       return NULL;
>     }
>
>     int main ()
>     {
>       pthread_t thr;
>       pthread_create (&thr, NULL, thread, NULL);
>       pthread_join (thr, NULL);
>       return 0;
>     }
>
> When do you propose that the cleanup handlers for the thread be called?

I’ll followup on this later, but currently it seems impossible to call
GC_INIT from a thread other than the initial thread [0].

Thanks,
Ludo’.

[0] 
http://article.gmane.org/gmane.comp.programming.garbage-collection.boehmgc/4490