#1062978 ncal: incorrect display of historical years

Package:
ncal
Source:
ncal
Description:
display a calendar and the date of Easter
Submitter:
Klaus Lux
Date:
2024-02-04 09:21:04 UTC
Severity:
normal
#1062978#5
Date:
2024-02-04 09:18:35 UTC
From:
To:
Dear Maintainers,

ncal shows a wrong days of week for many historical years.
Every 400 year cycle of the Gregorian calender starts at the same day of week (Saturday)
because that cycle has 146097 days (365*400+100-3 = 146097 = 773 * 27 * 7).
ncal displays the day of week right for future dates like 8400 but fails for
many historical years like 400, 800, 1600 or 424 (which should look like 2024).
It's kind of random because the calenders of the years 1200, 1224 or 1256 are OK.

There is no prio at all for me. I just tried that program the first time and did only
wan't to see whether it's able to handle historical years right because the common
mktime() implementations are unable to handle for such dates as well.

Kind Regards,
Klaus Lux