From: Anthony Williams (anthony_w.geo_at_[hidden])
Date: 2007-11-28 06:59:12
"Peter Dimov" <pdimov_at_[hidden]> writes:
> Anthony Williams:
>>> We should probably think of a way to enable the use of a monotonic clock
>>> with the absolute timeout overloads. It doesn't feel right to make the
>>> relative overloads the only way to access the functionality.
>> Yes, we should. However, absolute time is always going to have issues with
>> clock changes --- if I schedule for something now (2007-11-27 18:23:15 UTC
>> the current clock) to run tomorrow (2007-11-28 18:23:15 UTC), does it
>> for 24-hours from now, or for when-the-clock-reads the right time?
> These are UTC times. The monotonic clock (CLOCK_MONOTONIC) is not
> user-settable and for it, now+K always occurs after K seconds. For
> CLOCK_REALTIME, it schedules for the given time.
OK, so we have three overloads:
The question is: how do we implement a monotonic clock? CLOCK_MONOTONIC is
optional on POSIX, and GetTickCount wraps on Windows.
On Windows, we could use the System Up Time performance Counter, but I'm not
sure what the resolution is.
-- Anthony Williams Just Software Solutions Ltd - http://www.justsoftwaresolutions.co.uk Registered in England, Company Number 5478976. Registered Office: 15 Carrallack Mews, St Just, Cornwall, TR19 7UL
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