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Re: posix time functions
- From: Sam Pham <anhmn at yahoo dot com>
- To: Nick Garnett <nickg at ecoscentric dot com>
- Cc: eCos Discuss <ecos-discuss at sources dot redhat dot com>
- Date: Tue, 12 Oct 2004 11:40:51 -0700 (PDT)
- Subject: Re: [ECOS] posix time functions
Our application has the need of calling
clock_settime() to set the time. What are the
consequences of calling this function?
Thanks.
Sam
--- Nick Garnett <nickg@ecoscentric.com> wrote:
> David Brennan <eCos@brennanhome.com> writes:
>
> > We discovered a (perhaps) un-documented feature in
> the eCos posix
> > clock_settime and clock_gettime functions. Setting
> the time, changes
> > the system clock (number of ticks). The system
> clock should only be
> > changeable by the interrupt routine which is
> incrementing it. All
> > other code should really only have read access.
>
> Hmm, we have also had complaints that
> clock_settime() doesn't change
> enough and want it to alter the wallclock time as
> well. I guess you
> cannot please everyone.
>
> > Is there a chance this
> > could be changed? That is, if we fix it in the
> kernel, would that type
> > of patch be accepted.
>
> A patch that maintains an offet for CLOCK_REALTIME
> from the main
> timer and used that when calculating timer timeouts
> would be
> fine. Depending on how much gets changed, we might
> need an assignment
> for it, though.
>
> > I would think that setting the clock and
> > possibly losing alarms would be something that
> other people have
> > noticed before.
>
> To be honest, I don't think that many people call
> clock_settime().
> It's mainly there for completeness.
>
> --
> Nick Garnett eCos Kernel
> Architect
> http://www.ecoscentric.com/ The eCos and RedBoot
> experts
>
>
> --
> Before posting, please read the FAQ:
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>
>
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