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nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTIME?

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From: Michael Kerrisk <mtk.manpages@...>
To: lkml <linux-kernel@...>
Cc: Thomas Gleixner <tglx@...>, john stultz <johnstul@...>, Ingo Molnar <mingo@...>, Roman Zippel <zippel@...>
Subject: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTIME?
Date: Sunday, June 22, 2008 - 3:35 am

Thomas,

(I gues you are the right target for this?)

The POSIX.1 specification of nanosleep() says:

        But, except for the case of being interrupted by a signal, the
        suspension time shall not be less than the time  specified  by
        rqtp, as measured by the system clock CLOCK_REALTIME.


However, reading kernel/hrtimer.c:sys_nanosleep(), it appears that
CLOCK_MONOTONIC is used.

     return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);

Is there a reason to use CLOCK_MONOTONIC, instead of CLOCK_REALTIME?  Is it
intentional?  If yes, then I should document this in the man-pages.  If not,
then it should be fixed.

Cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
man-pages onlne: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html

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Messages in current thread:
nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTIME?, Michael Kerrisk, (Sun Jun 22, 3:35 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Bart Van Assche, (Mon Jun 23, 4:34 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Mon Jun 23, 5:48 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Roman Zippel, (Mon Jun 23, 8:43 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Tue Jun 24, 1:39 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Thomas Gleixner, (Wed Jun 25, 2:13 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Wed Jun 25, 2:16 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Bart Van Assche, (Tue Jun 24, 4:01 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Tue Jun 24, 4:27 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Bart Van Assche, (Tue Jun 24, 5:27 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Tue Jun 24, 5:31 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Bart Van Assche, (Mon Jun 23, 7:56 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Tue Jun 24, 1:18 am)
Re: nanosleep() uses CLOCK_MONOTONIC, should be CLOCK_REALTI..., Michael Kerrisk, (Tue Jun 24, 1:08 am)