On Sun, May 19, 2019 at 09:10:57PM +0300, Janne Blomqvist wrote:
> On Sun, May 19, 2019 at 7:15 PM Steve Kargl
> <s...@troutmask.apl.washington.edu> wrote:
> >
> > On Sun, May 19, 2019 at 01:40:59PM +0300, Janne Blomqvist wrote:
> > >
> > > +#if defined(HAVE_SIGACTION) && defined(HAVE_WAITPID)
> > > + static bool sig_init_saved;
> > > + bool sig_init = __atomic_load_n (&sig_init_saved,
> > > __ATOMIC_RELAXED);
> > > + if (!sig_init)
> > > + {
> > > + struct sigaction sa;
> > > + sa.sa_handler = &sigchld_handler;
> > > + sigemptyset(&sa.sa_mask);
> > > + sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
> > > + sigaction(SIGCHLD, &sa, 0);
> > > + __atomic_store_n (&sig_init_saved, true, __ATOMIC_RELAXED);
> > > + }
> > > +#endif
> >
> > Where do the prototypes for __atomic_load_n and __atomic_store_n
> > come from? On FreeBSD, it seems these are in stdatomic.h. Do
> > we need a HAVE_ATOMIC to include the header?
>
> They are GCC atomic builtins, they are always available, no need to
> include a header:
> https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
Thanks for the clarification. OK for trunk.
> > On a slightly different note, the nonstandard SYSTEM intrinsic
> > uses system(3) to execute a command. I believe that it will
> > leave zombies/orphaned children if a process is interrupted.
> > Perhap, SYSTEM should be reworked to use your EXECUTE_COMMAND_LINE.
>
> I believe any competent implementation of system() would wait for the
> child process. Since system() is synchronous, it can do the waiting
> inline without having to use a signal handler.
I'll need to check. I recall that
program foo
call system("Something_that_takes_along_time_to_execute")
end program foo
gfortran -o foo foo.f90
% foo
^C
Results in termination of the parent foo, and
Something_that_takes_along_time_to_execute is orphaned and
continues to run. It would probably be better to deliver
SIGKILL to child. I suppose that that is for another day.
--
Steve
