From: Henrik Grimler <henrik@grimler.se>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 47596@debbugs.gnu.org
Subject: bug#47596: File descriptor error when exiting emacs on android 11
Date: Mon, 05 Apr 2021 19:29:52 +0200 [thread overview]
Message-ID: <2215b2299da65d790a705d9b83051028a1a2b693.camel@grimler.se> (raw)
In-Reply-To: <838s5wdhef.fsf@gnu.org>
Hi,
I received feedback on the android issue tracker
https://issuetracker.google.com/issues/184380442
that the snippet:
> > #include <stdio.h>
> > int main()
> > {
> > fdopen (2, "w");
> > fclose (stderr);
> > }
is problematic, because:
> yes. you have two FILE*s that both think they own file descriptor 2.
> depending on what you're actually trying to do, you probably meant to
> use freopen(3) instead?
https://man7.org/linux/man-pages/man3/fopen.3.html
Does freopen make sense for buferr?
> > In emacs fdopen is run in init_standard_fds, where we have
> >
> > force_open (STDERR_FILENO, O_RDONLY);
> >
> > /* Set buferr if possible on platforms defining _PC_PIPE_BUF, as
> > they support the notion of atomic writes to pipes. */
> > #ifdef _PC_PIPE_BUF
> > buferr = fdopen (STDERR_FILENO, "w");
> > if (buferr)
> > setvbuf (buferr, NULL, _IOLBF, 0);
> > #endif
> > }
>
> This just creates a copy of stderr that has special buffering.
> Again,
> entirely valid for a C program to do that.
I probably should have included a bit more context in the android bug
report to better show what the code does.
Best regards,
Henrik Grimler
next prev parent reply other threads:[~2021-04-05 17:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-04 19:20 bug#47596: File descriptor error when exiting emacs on android 11 Henrik Grimler
2021-04-04 19:31 ` Eli Zaretskii
2021-04-04 20:11 ` Henrik Grimler
2021-04-05 8:14 ` Henrik Grimler
2021-04-05 8:59 ` Henrik Grimler
2021-04-05 9:48 ` Henrik Grimler
2021-04-05 12:57 ` Eli Zaretskii
2021-04-05 13:38 ` Henrik Grimler
2021-04-05 12:52 ` Eli Zaretskii
2021-04-05 12:50 ` Eli Zaretskii
2021-04-05 17:29 ` Henrik Grimler [this message]
2021-05-06 10:45 ` Lars Ingebrigtsen
2021-05-10 7:23 ` Henrik Grimler
2021-05-11 17:06 ` Henrik Grimler
2021-05-12 13:52 ` Lars Ingebrigtsen
2021-05-12 14:01 ` Eli Zaretskii
2022-06-29 10:47 ` Lars Ingebrigtsen
2022-06-29 13:25 ` Henrik Grimler via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-06-30 9:07 ` Lars Ingebrigtsen
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