Re: [tz] [PROPOSED] Fix ambiguous leapsecs by rolling up to a minute

On 9/13/21 11:41 AM, John Sauter wrote:

his means that conversion between UTC and local time is always possible and is reversible. The down side is that the GMT offset is not constant, but that is only true for a few seconds near the leap second.

That's another way to interpret the situation, yes. However, an advantage of the proposed patch's approach is that the UTC offset (tm_gmtoff) remains constant, thus satisfying the civil-time rules that Michael mentioned. The only difference between the proposed patch, and what you're suggesting, is that in the proposed patch when calculating the UTC offset a minute's seconds on or after an inserted leap second are all counted relative to the next minute, not relative to the previous one.