From: Paul Eggert <eggert@cs.ucla.edu>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: Daniele Nicolodi <daniele@grinta.net>, emacs-devel@gnu.org
Subject: Re: `message' not outputting the newline "atomically"
Date: Mon, 24 Jun 2019 15:03:01 -0700 [thread overview]
Message-ID: <68b398b1-3790-b32f-535d-6ea2518f79b8@cs.ucla.edu> (raw)
In-Reply-To: <m3tvcek6st.fsf@gnus.org>
On 6/24/19 2:33 PM, Lars Ingebrigtsen wrote:
> the code also calls code_convert_string, so I thought one
> more xmalloc didn't make much difference.
If code_convert_string could cause an infloop when reporting
low-on-memory messages, then we should fix that infloop too. In the
meantime we shouldn't make things worse by doing yet another heap
allocation.
One possibility would be to use an auto (C stack) buffer of size (min
(MAX_ALLOCA, PIPE_BUF)) bytes if that buffer is large enough; otherwise,
stick with the current code. This would handle the vast majority of
cases atomically, and the remaining cases would be no worse off than
they are now.
Still, it would be better if the code didn't need to copy the string
into a buffer at all. writev would work for that, since stderr is
unbuffered. There are other possibilities.
> * The patch also needs a FIXME comment saying it fixes only "message"
> output, not the other uses of stderr in Emacs.
> Well... that's kinda unusual. The commit message may say so, but
> having that in the code would be odd.
I think it's worth having that comment here. Someone reading this code
will reasonably wonder why we're going to all this trouble to
hand-buffer stderr here, when we don't bother doing it elsewhere. The
commit log is not a good place to document curious code like that.
next prev parent reply other threads:[~2019-06-24 22:03 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 14:12 `message' not outputting the newline "atomically" Lars Ingebrigtsen
2019-06-19 14:28 ` Andreas Schwab
2019-06-19 15:41 ` Eli Zaretskii
2019-06-19 15:47 ` Lars Ingebrigtsen
2019-06-19 16:05 ` Andreas Schwab
2019-06-19 23:22 ` Paul Eggert
2019-06-20 2:35 ` Eli Zaretskii
2019-06-20 7:47 ` Paul Eggert
2019-06-20 9:35 ` Lars Ingebrigtsen
2019-06-20 12:52 ` Eli Zaretskii
2019-06-20 12:55 ` Lars Ingebrigtsen
2019-06-20 13:13 ` Eli Zaretskii
2019-06-20 14:05 ` Andreas Schwab
2019-06-20 16:26 ` Paul Eggert
2019-06-20 16:45 ` Eli Zaretskii
2019-06-20 17:41 ` Paul Eggert
2019-06-20 18:06 ` Eli Zaretskii
2019-06-20 19:33 ` Paul Eggert
2019-06-21 5:46 ` Eli Zaretskii
2019-06-21 6:06 ` Eli Zaretskii
2019-06-22 0:20 ` Paul Eggert
2019-06-22 7:32 ` Eli Zaretskii
2019-06-22 19:14 ` Paul Eggert
2019-06-23 2:25 ` Eli Zaretskii
2019-06-23 8:34 ` Paul Eggert
2019-06-23 11:37 ` Lars Ingebrigtsen
2019-06-23 14:47 ` Eli Zaretskii
2019-06-23 17:32 ` Paul Eggert
2019-06-23 18:28 ` Eli Zaretskii
2019-06-23 12:53 ` Stefan Monnier
2019-06-23 14:51 ` Eli Zaretskii
2019-06-24 4:09 ` Stefan Monnier
2019-06-22 8:26 ` Andreas Schwab
2019-06-22 18:53 ` Paul Eggert
2019-06-22 19:00 ` Eli Zaretskii
2019-06-22 19:15 ` Paul Eggert
2019-06-22 19:48 ` Andreas Schwab
2019-06-20 13:32 ` Stefan Monnier
2019-06-20 16:28 ` Paul Eggert
2019-06-23 18:59 ` Daniele Nicolodi
2019-06-23 20:34 ` Paul Eggert
2019-06-23 20:42 ` Lars Ingebrigtsen
2019-06-23 21:00 ` Paul Eggert
2019-06-23 22:18 ` Lars Ingebrigtsen
2019-06-23 20:48 ` Daniele Nicolodi
2019-06-24 2:32 ` Eli Zaretskii
2019-06-24 2:51 ` HaiJun Zhang
2019-06-24 19:48 ` Lars Ingebrigtsen
2019-06-24 20:03 ` Daniele Nicolodi
2019-06-24 20:17 ` Lars Ingebrigtsen
2019-06-24 21:11 ` Paul Eggert
2019-06-24 21:33 ` Lars Ingebrigtsen
2019-06-24 22:03 ` Paul Eggert [this message]
2019-06-24 22:06 ` Paul Eggert
2019-06-24 22:28 ` Lars Ingebrigtsen
2019-06-24 22:47 ` Lars Ingebrigtsen
2019-06-25 16:03 ` Eli Zaretskii
2019-06-26 9:15 ` Lars Ingebrigtsen
2019-06-26 15:22 ` Eli Zaretskii
2019-06-27 10:52 ` Lars Ingebrigtsen
2019-06-26 18:27 ` Paul Eggert
2019-06-26 18:41 ` Eli Zaretskii
2019-06-26 18:58 ` Paul Eggert
2019-06-26 19:11 ` Eli Zaretskii
2019-06-26 19:36 ` Daniele Nicolodi
2019-06-27 2:34 ` Eli Zaretskii
2019-06-27 5:43 ` Paul Eggert
2019-06-30 20:11 ` Daniele Nicolodi
2019-07-01 7:41 ` Daniele Nicolodi
2019-07-01 14:39 ` Eli Zaretskii
2019-07-01 17:01 ` Daniele Nicolodi
2019-07-02 2:28 ` Eli Zaretskii
2019-07-02 7:58 ` Daniele Nicolodi
2019-07-02 14:47 ` Eli Zaretskii
2019-07-02 20:56 ` Daniele Nicolodi
2019-07-03 5:23 ` Eli Zaretskii
2019-07-01 17:03 ` Daniele Nicolodi
2019-07-02 2:26 ` Eli Zaretskii
2019-06-26 19:38 ` Paul Eggert
2019-06-25 16:06 ` Eli Zaretskii
2019-06-26 9:21 ` Lars Ingebrigtsen
2019-06-26 15:23 ` Eli Zaretskii
2019-06-27 11:03 ` Lars Ingebrigtsen
2019-06-27 13:31 ` Eli Zaretskii
2019-06-28 8:30 ` Lars Ingebrigtsen
2019-07-03 7:31 ` Paul Eggert
2019-07-03 7:41 ` Eli Zaretskii
2019-07-03 7:47 ` Eli Zaretskii
2019-07-03 7:57 ` Eli Zaretskii
2019-07-03 8:45 ` Paul Eggert
2019-07-03 9:30 ` Eli Zaretskii
2019-07-03 23:08 ` Paul Eggert
2019-07-04 13:24 ` Eli Zaretskii
2019-07-07 1:16 ` Paul Eggert
2019-07-07 14:51 ` Eli Zaretskii
2019-07-08 22:35 ` Richard Copley
2019-07-09 2:33 ` Eli Zaretskii
2019-07-09 13:45 ` Richard Copley
2019-07-09 15:16 ` Eli Zaretskii
2019-07-09 2:47 ` Paul Eggert
2019-07-09 16:39 ` Eli Zaretskii
2019-07-09 18:12 ` Paul Eggert
2019-07-09 18:32 ` Eli Zaretskii
2019-07-09 18:44 ` Lars Ingebrigtsen
2019-07-09 19:17 ` Eli Zaretskii
2019-07-14 0:42 ` Paul Eggert
2019-07-14 6:01 ` Eli Zaretskii
2019-06-25 16:08 ` Eli Zaretskii
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