[LEAPSECS] Crunching Bulletin B numbers (POSIX time)

[Poul-Henning Kamp]

In message <6C98B1ED-8AF0-4321-99EF-BC57E1F5CA8D at batten.eu.org>, Ian Batten writes

:

>However, with or without leapseconds, Posix time is still monotonic

>both in time_t and , and I would be incredibly dubious of systems

>that perform interval timing using ctime or localtime or gmtime,

>rather than the raw time_t.


time_t is not guaranteed to be monotonic.

If you want a monotonic timestamp nobody messes with, you want to
call clock_gettime(CLOCK_MONOTONIC,...) which returns a timestamp
that is _not_ referenced to any timescale, but which *is* guaranteed
to be monotonic.


>> That is why, we cannot have some POSIX systems inserting leap-seconds in

>> to time_t and some POSIX systems not doing so.

>

>I don't think that's the discussion, is it?


It very much is, without a 10-20 year leap-second horizon, there is no way
we can teach time_t or the time_t successor about leapseconds, and live
up to the POSIX "isolated system" requirement.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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