the ``need'' for POSIX times

D. J. Bernstein djb at cr.yp.to
Thu Oct 8 17:15:52 UTC 1998


Antoine Leca writes:
> I just need to add 7*86400L to my start value.

Is that actually guaranteed to work with Markus's library? Don't you get
an invalid time if nsec starts out above 999999999?

> They (and I) want reliable and mostly straightforward ways to
> resolve *their* problems, not trying to write convolutate
> programs to handle the fantasy of Earth movement.

With libtai the programmer simply says what he means:

   caltime_utc(&ct,&sec,(int *) 0,(int *) 0); /* gmtime() */
   ct.date.day += 7;
   caltime_tai(&ct,&sec); /* mktime() */

What exactly is ``convoluted'' about that? How has libtai ``impeded''
time handling?

> BTW, what is your objective? do you think we should take
> your library and pasting it in the C standard?

Of course not. libtai is still under development.

> Also, where do you find overwhelming costs behind the
> adoption of Markus's proposal?

Markus's proposal is a disaster from the programmer's point of view. I
didn't say this was an ``overwhelming'' cost; I simply said that it's
much larger than the cost of distributing leap-second tables.

---Dan
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