Cc: linux-kernel@vger.kernel.org
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Date: Thu, 06 Sep 2007 15:38:58 +0200
From: "Michael Kerrisk" <mtk-manpages@gmx.net>
In-Reply-To: <a36005b50709060434u35d8db01n7cc448e98fdbdd37@mail.gmail.com>
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Subject: Re: O_CLOEXEC / MSG_CMSG_CLOEXEC documentation
To: "Ulrich Drepper" <drepper@gmail.com>
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Ulrich,

> On 9/5/07, Michael Kerrisk <mtk-manpages@gmx.net> wrote:
> >     O_CLOEXEC (Since Linux 2.6.23)
> >           Enable   the  close-on-exec  flag  for  the  new  file
> >           descriptor.  This is useful in multithreaded  programs
> >           since  using  a separate fcntl(2) F_SETFD operation to
> >           set the FD_CLOEXEC flag does not suffice to avoid race
> >           conditions  in multithreaded programs where one thread
> >           opens a file descriptor at the same  time  as  another
> >           thread does a fork(2) plus execve(2).
> 
> Correct,

Good.  Thanks.

> although you might want to reconsider the repetition of "in
> multithreaded programs".

Yes.

> Plus, it's also useful in other programs since it avoids the
> additional system call to fcntl.

Okay, I may add some words about this.

Cheers,

Michael
-- 
Michael Kerrisk
maintainer of Linux man pages Sections 2, 3, 4, 5, and 7 

Want to help with man page maintenance?  
Grab the latest tarball at
http://www.kernel.org/pub/linux/docs/manpages , 
read the HOWTOHELP file and grep the source 
files for 'FIXME'.

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