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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Dave Jones <davej@redhat.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: 3.5.rc2 tty buffering bug ?
Date: Fri, 15 Jun 2012 18:32:54 +0800	[thread overview]
Message-ID: <CAM_iQpV4WOSafe8X9pjV++CUJyb30VDOVVKOiusA9OxGyj6CTw@mail.gmail.com> (raw)
In-Reply-To: <20120614161331.GA29687@redhat.com>

On Fri, Jun 15, 2012 at 12:13 AM, Dave Jones <davej@redhat.com> wrote:
> but when redirected to a file, sometimes it prints what we expect, but other times
> (if the child exits first) it seems to print..
>
> begin
> child
> end
> begin
> parent
> end
>
>
> How does 'begin' get printed a second time ?
>

setbuf(3) said:

"
Normally  all files are block buffered. [...]
If a stream refers to a terminal (as stdout normally does) it is line buffered.
The standard error stream stderr is always unbuffered by default.
"
So when you redirect stdout to a file, "begin\n" is buffered too, both
in child and in parent.

      parent reply	other threads:[~2012-06-15 10:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-14 16:13 Dave Jones
2012-06-14 16:22 ` Dave Jones
2012-06-14 16:30 ` Andreas Schwab
2012-06-14 16:41 ` Alan Cox
2012-06-15 10:32 ` Cong Wang [this message]

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