2 ms·

This isn't what they're talking about, though. Say your boss says "your work shift starts at 9am". That isn't an instant in time, it's all about the display r

This isn't what they're talking about, though. Say your boss says "your work shift starts at 9am". That isn't an instant in time, it's all about the display rule: clock says 9am and you're not at work, you're fired. We don't typically care about this because we work 9-5 M-F, and daylight savings time conveniently happens at 2am on Sunday morning. But someone was told to come in at 2am this morning and couldn't actually do that because 1:59:59 became 3:00:00. How do you handle that? It's not a code problem, it's a business rules problem.

ivan_gammel 5y ago
No, this is not a display rule. This is the domain data type "local time", which stores time component without offset or time zone. Data stored this way is basically telling that regardless of current UTC offset, locally on the clock there will be always the same time shown. Display rules are saying how exactly this time will be displayed on the clock (i.e. locale, 12/24 hour format etc). Wall clocks usually do not show "am/pm" information, so the same time indeed may occur twice on them.
- progval 5y ago
  "wall-clock time" does not mean what is shown by a literal wall clock. It means the time used by people who are not computer engineers. https://en.wikipedia.org/wiki/Elapsed_real_time https://en.wikipedia.org/wiki/Elapsed_real_time When the parent comment said "Wall clock times may occur twice", they meant between 2 and 3am when when leaving DST.