* process doesn't terminate when closing streams from another thread
@ 2015-09-06 14:44 Nuno Gonçalves
2015-09-06 17:00 ` Szabolcs Nagy
2015-09-09 4:47 ` Rich Felker
0 siblings, 2 replies; 4+ messages in thread
From: Nuno Gonçalves @ 2015-09-06 14:44 UTC (permalink / raw)
To: musl
I'm having problems when closing streams from another thread.
The following code:
static void *func(void *arg)
{
fclose(stdout);
fprintf(stderr,"Thread about to exit\n");
return 0;
}
int main(int argc, char **argv)
{
int thread_id;
pthread_create(&thread_id,NULL,&func,NULL);
pthread_join(thread_id,NULL);
fprintf(stderr,"Process about to terminate\n");
return 0;
}
Prints:
root@OpenWrt:/tmp# ./myapp_withmusl
Thread about to exit
Process about to terminate
But never returns! I have to send it a SIGINT.
This happens on target-mips_34kc_musl-1.1.11.
Thanks,
Nuno
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: process doesn't terminate when closing streams from another thread
2015-09-06 14:44 process doesn't terminate when closing streams from another thread Nuno Gonçalves
@ 2015-09-06 17:00 ` Szabolcs Nagy
2015-09-07 4:50 ` Rich Felker
2015-09-09 4:47 ` Rich Felker
1 sibling, 1 reply; 4+ messages in thread
From: Szabolcs Nagy @ 2015-09-06 17:00 UTC (permalink / raw)
To: musl
* Nuno Gon?alves <nunojpg@gmail.com> [2015-09-06 15:44:45 +0100]:
> I'm having problems when closing streams from another thread.
>
> The following code:
>
> static void *func(void *arg)
> {
> fclose(stdout);
> fprintf(stderr,"Thread about to exit\n");
> return 0;
> }
>
> int main(int argc, char **argv)
> {
> int thread_id;
s/int/pthread_t/
> pthread_create(&thread_id,NULL,&func,NULL);
> pthread_join(thread_id,NULL);
> fprintf(stderr,"Process about to terminate\n");
> return 0;
> }
>
> Prints:
>
> root@OpenWrt:/tmp# ./myapp_withmusl
> Thread about to exit
> Process about to terminate
>
> But never returns! I have to send it a SIGINT.
>
yes, musl fflushes stdout on fflush(0) even if
it is closed. (fflush(0) is called at exit,
fflushing a closed stream is undefined behaviour).
this might be a musl bug.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: process doesn't terminate when closing streams from another thread
2015-09-06 17:00 ` Szabolcs Nagy
@ 2015-09-07 4:50 ` Rich Felker
0 siblings, 0 replies; 4+ messages in thread
From: Rich Felker @ 2015-09-07 4:50 UTC (permalink / raw)
To: musl
On Sun, Sep 06, 2015 at 07:00:33PM +0200, Szabolcs Nagy wrote:
> * Nuno Gon?alves <nunojpg@gmail.com> [2015-09-06 15:44:45 +0100]:
> > I'm having problems when closing streams from another thread.
> >
> > The following code:
> >
> > static void *func(void *arg)
> > {
> > fclose(stdout);
> > fprintf(stderr,"Thread about to exit\n");
> > return 0;
> > }
> >
> > int main(int argc, char **argv)
> > {
> > int thread_id;
>
> s/int/pthread_t/
>
> > pthread_create(&thread_id,NULL,&func,NULL);
> > pthread_join(thread_id,NULL);
> > fprintf(stderr,"Process about to terminate\n");
> > return 0;
> > }
> >
> > Prints:
> >
> > root@OpenWrt:/tmp# ./myapp_withmusl
> > Thread about to exit
> > Process about to terminate
> >
> > But never returns! I have to send it a SIGINT.
> >
>
> yes, musl fflushes stdout on fflush(0) even if
> it is closed. (fflush(0) is called at exit,
> fflushing a closed stream is undefined behaviour).
>
> this might be a musl bug.
Yes, this is indeed a musl bug. Getting the right fix is non-trivial
but I think it will involve having fclose unlock the FILE but ensure
that its contents are setup such that the exit-time code behaves as a
no-op.
Rich
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: process doesn't terminate when closing streams from another thread
2015-09-06 14:44 process doesn't terminate when closing streams from another thread Nuno Gonçalves
2015-09-06 17:00 ` Szabolcs Nagy
@ 2015-09-09 4:47 ` Rich Felker
1 sibling, 0 replies; 4+ messages in thread
From: Rich Felker @ 2015-09-09 4:47 UTC (permalink / raw)
To: musl
On Sun, Sep 06, 2015 at 03:44:45PM +0100, Nuno Gonçalves wrote:
> I'm having problems when closing streams from another thread.
>
> The following code:
>
> static void *func(void *arg)
> {
> fclose(stdout);
> fprintf(stderr,"Thread about to exit\n");
> return 0;
> }
>
> int main(int argc, char **argv)
> {
> int thread_id;
> pthread_create(&thread_id,NULL,&func,NULL);
> pthread_join(thread_id,NULL);
> fprintf(stderr,"Process about to terminate\n");
> return 0;
> }
>
> Prints:
>
> root@OpenWrt:/tmp# ./myapp_withmusl
> Thread about to exit
> Process about to terminate
>
> But never returns! I have to send it a SIGINT.
>
> This happens on target-mips_34kc_musl-1.1.11.
>
> Thanks,
Thanks for the report. This should now be fixed (in git master). Let
me know if you still have problems.
Rich
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-09-09 4:47 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-09-06 14:44 process doesn't terminate when closing streams from another thread Nuno Gonçalves
2015-09-06 17:00 ` Szabolcs Nagy
2015-09-07 4:50 ` Rich Felker
2015-09-09 4:47 ` Rich Felker
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