Re: No NONBLOCK flag for dup3() or epoll_create1()?

From: Michael Kerrisk
Date: Fri Aug 29 2008 - 16:44:23 EST


Ping!

On Wed, Aug 20, 2008 at 6:49 PM, Michael Kerrisk
<mtk.manpages@xxxxxxxxxxxxxx> wrote:
> Ulrich
>
> I've been doing some testing (2.6.27-rc3) of your new
> file-descriptor-creating syscalls that accept flags. According to
>
> http://udrepper.livejournal.com/20407.html
>
> all of the system calls should accept a *_NONBLOCK flag. All of them do,
> except for two:
> dup3(olfd, newfd, flags)
> and
> epoll_create1(flags).
>
> For epoll_create1() this certainly appears to be an oversight, since I can't
> think of a reason not to support *_NONBLOCK.
>
> For dup3() it is perhaps also an oversight. However, it's not really clear
> to me whether supporting O_NONBLOCK makes sense, since that would change the
> file status flags of the open file description that is (also) referred to by
> oldfd. (Furthermore, given a open file description for which O_NONBLOCK is
> already enabled, it is not possible to make a dup3() call that disables
> O_NONBLOCK, which is an odd asymmetry in the API.) What are your thoughts
> on
> this?
>
> Cheers,
>
> Michael
>
>



--
Michael Kerrisk
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