What unit of time returns timeIntervalSinceDate?

Question

What unit of time returns timeIntervalSinceDate? Is it seconds, milliseconds or something else?

The documentation says that it returns NSTimeInterval, but what unit of time is this value?

Answer 1

It returns the number of seconds as the value of NSTimeInterval .

From this documentation page :

NSTimeInterval is always specified in seconds; it gives submillisecond accuracy over 10,000 years.

Answer 2

Well NSDate docs shows a function prototype as:

- (NSTimeInterval)timeIntervalSinceDate:(NSDate *)anotherDate

And the basic doc data types states:

NSTimeInterval is always specified in seconds; this gives submillisecond accuracy over 10,000 years.