Time Resolution

Ashley Yakeley ashley at semantic.org
Tue Feb 1 20:42:43 EST 2005

In article <87fz0gttd2.fsf at qrnik.zagroda>,
 Marcin 'Qrczak' Kowalczyk <qrczak at knm.org.pl> wrote:

> So I have two proposals for the resolution of Haskell's representation
> of absolute time:
> 1. Use nanoseconds.
> 2. Use an implementation-dependent unit (will be probably nanoseconds
>    or microseconds with current implementations, but the interface
>    will not have to be changed if more accurate delays become practical
>    in 10 years).

Of course the clock doesn't actually return absolute time per se if it's 
set to UTC.

It looks like we may need three types here:

* one for TAI

* one for POSIX time, which is a broken encoding of UTC

* one for correct encoding of UTC

Can we assume that the system clock will be set to UTC? This is 
apparently in the POSIX standard. What about on Windows platforms? If 
so, the system clock should return POSIX time.

Do we want the same resolution in all three? Should it be fixed or 
platform-dependent? Bear in mind that there are applications for this 
that may not involve the system clock at all.

Ashley Yakeley, Seattle WA

More information about the Libraries mailing list