Re: Time resolution in Emacs

[Paul Eggert <eggert@cs.ucla.edu>]

On 4/25/22 09:10, Eli Zaretskii wrote:
> What do you do if you get a timestamp whose
> fractional part looks like .123000 -- do you consider this to be
> millisecond resolution or microsecond resolution?

The latter. That's standard practice, pretty much everywhere.


> we'd
> get in trouble as result of trivial arithmetics on timestamps

Whatever trouble we get into, will be less trouble than we get with 
arbitrarily converting to a resolution that differs from that of the 
incoming timestamp.

More generally, we can't do a perfect job with timestamp resolution, but 
that's OK. There's never perfection in timestamps anyway. What we can 
do, is do a better job than what we're currently doing.


> It's very hard to keep only that many significant digits when working
> with fractional numbers.

It's not hard to send a textual timestamp. Emacs does this sort of thing 
routinely when printing floats, and fractions are easier than floats. 
And Emacs code that computes timestamps internally can continue to use 
whatever resolution it is currently using; it doesn't need to arbitrary 
limit that resolution.