Re: Minibuffer tray to display current time and date

[Jorge A. Alfaro-Murillo]

Dan Espen writes:

> jorge.alfaro-murillo@yale.edu (Jorge A. Alfaro-Murillo) writes: 
>
> > Thanks... I see, it seems like every time that the 
> > display-timer  runs it updates its interval. That doesn't seem 
> > very efficient,  but there could be a good reason why they did 
> > it that way. 
>
> How is that not efficient? 
>
> That's exactly the way I did it about 30 years ago on an IBM 
> mainframe. Works for anything you want running at a regular 
> interval.  First pop is 60 seconds. Odds are, it will pop at 61, 
> or even 62 depending on system load, etc. So, the next wait 
> should be 60, 59, or 58.

Well, I think that (run-at-time time repeat ...) already schedules 
the times to run at the correct times even if one is late, so 
there is no need to reschedule again even if the system load is 
high and misses one timing or more. The documentation in (info 
"(elisp) Timers") seems to imply so:

"A repeating timer nominally ought to run every REPEAT seconds, 
but remember that any invocation of a timer can be late.  Lateness 
of one repetition has no effect on the scheduled time of the next 
repetition.  For instance, if Emacs is busy computing for long 
enough to cover three scheduled repetitions of the timer, and then 
starts to wait, it will immediately call the timer function three 
times in immediate succession (presuming no other timers trigger 
before or between them)." 

Now the last part could be problematic if emacs is stopped or the 
systems goes into hibernation (?). But `timer-max-repeats' takes 
care of that. Am I missing something?

Best,
--
Jorge.