[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Strange behaviour on 'read' from a pipe
From: |
Andreas Schwab |
Subject: |
Re: Strange behaviour on 'read' from a pipe |
Date: |
Sun, 01 Apr 2012 11:53:12 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.94 (gnu/linux) |
Chet Ramey <chet.ramey@case.edu> writes:
> On 3/31/12 9:19 AM, Lluís Batlle i Rossell wrote:
>> Hello,
>>
>> I have this script, that I've found to never write "DONE" in my systems, with
>> bash 4.0, 4.1, 4.2.. until 4.2-p20, my last test.
>>
>> However, in irc some people told me it prints DONE for them. If I run the
>> script with
>> bash under 'strace -f', it also prints DONE.
>
> It looks like a simple race condition. I suspect that the scheduler
> arranges things so that the child process ends up exiting between the
> open and the read, but I don't have any real evidence to back it up.
Note that the opening of the pipe as part of the redirection in the
parent blocks until there is a writer, ie. until the child opens the
pipe. Can this open call return EINTR?
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/01
- Re: Strange behaviour on 'read' from a pipe,
Andreas Schwab <=
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/01
- Re: Strange behaviour on 'read' from a pipe, Chet Ramey, 2012/04/01
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/01
- Re: Strange behaviour on 'read' from a pipe, Chet Ramey, 2012/04/01
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/02
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/02
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/02
- Re: Strange behaviour on 'read' from a pipe, Greg Wooledge, 2012/04/02
- Re: Strange behaviour on 'read' from a pipe, Lluís Batlle i Rossell, 2012/04/02