Seconds from 19xx to Date (and visa versa)

[Norman Diamond]

In article <5522 at hoptoad.uucp>, pozar at hoptoad.uucp (Tim Pozar) writes:
 
>     Does anyone have a routine to change back and forth between
> seconds from 19xx to a Year, Month, Day sort of Date?

You need more than a routine to do this.  You need a database of when
leap seconds have occurred.  Sometimes on June 30th or December 31st,
the last minute runs from 11:59:00 to 11:59:60 (sixty-one seconds) in
order to compensate for wobbles in the earth's rotation.  These do
not happen as regularly as leap days, so their occurrences cannot be
computed by a a routine; you need a database.

(The dpANSI C standard had the field for seconds redefined to allow a
value of 60 for exactly this reason.  I proposed the same correction
to the committees standardizing Extended Pascal.)
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