From: "H. Peter Anvin" <hpa@zytor.com>
To: mtk.manpages@gmail.com
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Ulrich Drepper <drepper@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: dup2() vs dup3() inconsistency when
Date: Thu, 09 Oct 2008 10:21:08 -0700 [thread overview]
Message-ID: <48EE3D84.6000003@zytor.com> (raw)
In-Reply-To: <cfd18e0f0810090510i87f088fi9eeea829ae2b58c1@mail.gmail.com>
Michael Kerrisk wrote:
> Al,
>
> your 2008-07-26 commit 6c5d0512a091480c9f981162227fdb1c9d70e555 for
> fs/fcntl.c:sys_dup3 contains
>
> + if (unlikely(oldfd == newfd))
> + return -EINVAL;
>
> This makes dup2() and dup3() differ with respect to the oldfd==newfd
> case (dup2() becomes a no-op, just returning oldfd, dup3() gives the
> EINVAL error.
>
> Your commit log doesn't explain the rationale for this change. What
> is it? (I could guess that it is to error on a case that may be a
> user programming error, but I want to check this with you, so that I
> add the right text to the man page.)
>
The dup2() behavior comes from the logical consequence of dup2()'s
"close on reuse"; one would think it would be logical for dup3() to
behave the same way.
-hpa
next prev parent reply other threads:[~2008-10-09 17:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-09 12:10 dup2() vs dup3() inconsistency when Michael Kerrisk
2008-10-09 17:21 ` H. Peter Anvin [this message]
2008-10-09 20:31 ` Ulrich Drepper
2008-10-09 20:43 ` H. Peter Anvin
2008-10-09 20:52 ` Ulrich Drepper
2008-10-09 20:57 ` H. Peter Anvin
2008-10-09 21:04 ` Ulrich Drepper
2008-10-10 5:04 ` Michael Kerrisk
2008-10-10 12:09 ` Bernd Petrovitsch
2008-10-10 12:15 ` Michael Kerrisk
2008-10-10 13:02 ` Bernd Petrovitsch
2008-10-10 13:15 ` Michael Kerrisk
2008-10-10 13:31 ` Bernd Petrovitsch
2008-10-10 5:01 ` Michael Kerrisk
2008-10-10 13:43 ` Heikki Orsila
[not found] <bl2EV-7G2-9@gated-at.bofh.it>
[not found] ` <bl7v3-5sk-17@gated-at.bofh.it>
[not found] ` <blasN-OS-9@gated-at.bofh.it>
[not found] ` <blaCu-Z0-11@gated-at.bofh.it>
[not found] ` <blaMj-18o-23@gated-at.bofh.it>
[not found] ` <blaMj-18o-21@gated-at.bofh.it>
[not found] ` <bliqg-2DH-1@gated-at.bofh.it>
2008-10-10 11:42 ` Bodo Eggert
2008-10-10 11:59 ` Michael Kerrisk
2008-10-10 13:19 ` Bodo Eggert
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