NTP and POSIX Time in conflict?

Bradley White bww at acm.org
Mon Dec 4 22:48:27 UTC 2000

> 1.  I have heard it claimed that the broken-ness of posix time 
> prevented NTP from handling leap seconds correctly.  Would you care 
> to comment on this?  Specifically, what specific brokenness causes 
> what problem?

POSIX legislates a particular mapping between time_t's and the time of
day (e.g., 536457599 shall correspond to "Wed Dec 31 23:59:59 UTC 1986").
So, POSIX time must be adjusted over leap seconds.  The premier NTP
implementation goes to convoluted lengths to perform that adjustment.

The "correct" way to handle leap seconds is a matter of opinion, but
`ado-right' stalwarts would contend that using a continuous time base
results in a better system, and treating time_t as opaque gets you

See time2posix(3) in the ado source for more details.


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