ios - Understanding NSDate difference between hours -

if check date (at 20:05 in evening)

2015-07-14 17:05:41 +0000 

so 3 hours difference gone ? guess zone thing.

my basic question is, can leave assuming add same hours when set alarm notification date ?

e.g if set alarm @ real time- 20:05 , date shows 17:05 , in same hour of day- means 20:05 ?? or wrong work that?

twice year people complain alarms going off @ wrong time when daylight savings time starts or end.

nsdate logs date in utc, not quite same gmt, greenwich mean time (british summertime). if both @ our watches right now, see different times, nsdate report same time on world.

if wants set alarm 20:05 tomorrow need functionality in nscalendar find out nsdate set. on 363 days of year, 20:05 tomorrow 24 hours or 86,400 seconds after 20:05 today. on 2 days of year, isn't.

of course if set alarm 20:05 tomorrow , take flight london new york, can guess whether wanted alarm @ 20:05 london or new york time.