[fpc-devel] NowUTC in the RTL

[zeljko]

On Friday 09 of December 2011 16:10:54 Sven Barth wrote:
> Am 09.12.2011 15:37, schrieb zeljko:
> > On Friday 09 of December 2011 14:52:56 Sven Barth wrote:
> >  > Am 09.12.2011 13:30, schrieb Michael Schnell:
> >  > > On 12/09/2011 01:17 PM, Felipe Monteiro de Carvalho wrote:
> >  > >> I would like to define it like this: "FPGetTickCount returns the
> >  > >> 
> >  > >> amount of ticks since an unspecified initial time. This initial
> >  > >> time
> >  > >> 
> >  > >> is unknown, but is fixed for the entire duration of the
> >  > >> application.
> >  > >> 
> >  > >> Ticks are time intervals and all of them have the same duration,
> >  > >> but
> >  > >> 
> >  > >> their exact meaning in terms of real world units like milliseconds
> >  > >> is
> >  > >> 
> >  > >> unspecified. FPGetTickCount is not affected by timezones and also
> >  > >> not
> >  > >> 
> >  > >> by the user changing the system clock." So it matches
> >  > >> 
> >  > >> Windows.GetTickCount well but still is flexible enough to be
> >  > >> 
> >  > >> implemented in other platforms.
> >  > > 
> >  > > What if the PC is polling a time server or similar ? IMHO
> > 
> > FPGetTickCount
> > 
> >  > > should not be affected by such interference. This rules out using OS
> >  > > 
> >  > > time API calls.
> >  > 
> >  > The description of Felipe mathes Windows' GetTickCount (number of
> >  > 
> >  > milliseconds since system start) and Linux' MONOTONIC_RAW time (or
> >  > 
> >  > however it is called exactly). So I don't see why this should rule out
> >  > 
> >  > OS time API calls...
> > 
> > No, MONOTONIC_RAW is introduced in 2.6.26 afair, so it won't run on
> > older kernels.
> 
> My comment was less for which timer type we should support, but more to
> have a argument for what Felipe said.

Ok, also I forgot to mention that MONOTNIC_RAW isn't interrupted by ntp but 
MONOTONIC IS so it's big diff.

zeljko

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freepascal.org/pipermail/fpc-devel/attachments/20111209/80801a45/attachment.html>