From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
Cc: Stefan Monnier <monnier@iro.umontreal.ca>, emacs-devel@gnu.org
Subject: Re: why "in_sighandler"?
Date: Mon, 21 Aug 2006 17:58:02 +0900 [thread overview]
Message-ID: <wlzmdypisl.wl%mituharu@math.s.chiba-u.ac.jp> (raw)
In-Reply-To: <44E972EC.8000903@swipnet.se>
>>>>> On Mon, 21 Aug 2006 10:46:36 +0200, Jan Djärv <jan.h.d@swipnet.se> said:
>>> Read the single exception: "when a signal interrupts an unsafe
>>> function and the signal-catching function calls an unsafe
>>> function, the behavior is undefined."
>>
>> So, you interpret that ``what are interrupted by a signal'' are all
>> the functions in execution on the whole threads in the process, not
>> just a single function in execution on the thread that the signal
>> is delivered to? I don't think that is a natural interpretation.
> I don't see the line "what are interrupted by a signal" in the
> quote, so I'm not sure what you mean.
> My interpretation is that it is unsafe to call lock/unlock from a
> thread and from a signal handler at the same time, if they operate
> on the same mutex. That is what the original hang was all about.
The standard says "when a signal interrupts an unsafe function ...".
My interpretation is that a signal interrupts *only* the function in
execution on the thread that the signal is delivered to, but the
signal does not interrupt the functions in execution on the other
threads.
>> As I said earlier, the current Emacs implementation calls malloc
>> within a signal handler with the help of BLOCK_INPUT relying on the
>> assumption that it is safe unless the signal interrupted
>> malloc-related functions.
> But this only works for the Emacs main thread, not the Gnome
> threads.
And according to the above interpretation, functions that are executed
on non-main threads are irrelevant.
YAMAMOTO Mitsuharu
mituharu@math.s.chiba-u.ac.jp
next prev parent reply other threads:[~2006-08-21 8:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-20 6:51 why "in_sighandler"? Stefan Monnier
2006-08-20 16:37 ` Jan D.
2006-08-20 18:22 ` Stefan Monnier
2006-08-21 0:08 ` YAMAMOTO Mitsuharu
2006-08-21 6:18 ` Jan Djärv
2006-08-21 6:44 ` YAMAMOTO Mitsuharu
2006-08-21 7:19 ` Jan Djärv
2006-08-21 8:13 ` YAMAMOTO Mitsuharu
2006-08-21 8:46 ` Jan Djärv
2006-08-21 8:58 ` YAMAMOTO Mitsuharu [this message]
2006-08-21 11:32 ` Jan Djärv
2006-08-22 0:22 ` YAMAMOTO Mitsuharu
2006-08-22 6:38 ` Jan Djärv
2006-08-22 7:39 ` YAMAMOTO Mitsuharu
2006-08-22 8:23 ` Jan Djärv
2006-08-22 8:34 ` YAMAMOTO Mitsuharu
2006-08-22 18:00 ` Jan Djärv
2006-08-22 9:43 ` Andreas Schwab
2006-08-21 11:13 ` Richard Stallman
2006-08-21 12:55 ` Jan Djärv
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