On 01-04-2026 21:41, Alvar Penning wrote:
> Hi all,
> 
> The following diff fixes the incorrect leap year detection within
> newsyslog(8), I stumbled across while checking my other diff.
> 
> Prior, a year was considered a leap year if
> - it is divisible by 4,
> - it is NOT divisible by 100 and
> - it is divisible by 400.
> 
> Unless I am really tired right now, this should be impossible. There
> should be no number divisible by 400 but NOT divisible by 100.
> Furthermore, enforcing that every leap year must be divisible by 400
> makes no real sense.
> 
> A more straight forward implementation follows, handling both the
> "divisible by 4 and not 100" and the "divisible by 4, 100 and 400" case.
> 
> Best,
> Alvar

If your year is divisible by 400 it is a leap despite the fact that 
years divisible by 100 are not.  It is to stop the seasons drifting.

https://www.wolframalpha.com/input?i=leap+year

hth

Fred