[fpc-devel] NowUTC in the RTL

[Hans-Peter Diettrich]

Jonas Maebe schrieb:
> 
> On 09 Dec 2011, at 13:47, Michael Van Canneyt wrote:
> 
>> I know nothing about OS/2-eCS, but the same arguments as for Go32V2 
>> apply as far as I am concerned. If all these platforms can guarantee 
>> returning correct UTC time, I do not see why we would not introduce it.
> 
> Afaik the original point was that some people were interested in some 
> kind of timestamp that does not jump around (except possibly when 
> overflowing).

I.e. means to quickly build time *differences*, for performance and 
progress display. That's almost the only use for GetTickCount, and for 
that purpose the underlying source must be monotonic.

> I don't think anyone particularly needed "the time in 
> UTC". Therefore, something like FPGetTickCount seems much more 
> appropriate than NowUTC, and it also solves the problem that some 
> targets may not support returning the time in UTC.

In contrast to Now with local time (with DST and timezones), NowUTC 
should return monotonic, platform independent and comparable absolute 
time values.

When some (very old) platforms don't support UTC, we could at least 
implement something like GetTimeStamp, that returns absolute time values 
at least for the current platform. These values should be usable as 
unique (monontonic) time stamps in e.g. log files.

DoDi