Re: Add pselect, ppoll system calls.

From: Bernd Petrovitsch
Date: Tue Jun 14 2005 - 09:18:03 EST


On Tue, 2005-06-14 at 16:07 +0200, =?ISO-8859-1?Q?Mattias Engdeg=E5rd?=
wrote:
> >Monotonic clocks are guaranteed to not go backward. A sudden warp 35
> >seconds into the future when you have timers set for 15 and 20
> >seconds into the future is still ugly....
>
> I don't have the POSIX specs handy, but I see no reason we could not let
> it use a warpless monotonic clock.

You have already one - the uptime of the system.

> The problem of timeouts going wild when time is being warped applies
> to syscalls using relative timeouts as well. Even when a relative
> timeout is wanted, it is usually transformed (via gettimeofday or

Doing "Relative timeouts" with "gettimeofday()" is a strategic error.
Specify the timeout und use (the return value of) times(2) for this.

Use "gettimeofday()" and similar just if (and only if) you communicate
with the user (read: that is a pure user interface issue).

Bernd
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