timeIntervalSinceReferenceDate
The interval between 00:00:00 UTC on 1 January 2001 and the current date and time.
Declaration
class var timeIntervalSinceReferenceDate: TimeInterval { get }Return Value
The interval between the system’s absolute reference date (00:00:00 UTC on 1 January 2001) and the current date and time.
Discussion
This method is the primitive method for NSDate. If you subclass NSDate, you must override this method with your own implementation for it.