How to convert NSTimeInterval to int?

Direct assignment:

NSTimeInterval interval = 1002343.5432542;
NSInteger time = interval;
//time is now equal to 1002343

NSTimeInterval is a double, so if you assign it directly to a NSInteger (or int, if you wish) it'll work. This will cut off the time to the nearest second.

If you wish to round to the nearest second (rather than have it cut off) you can use round before you make the assignment:

NSTimeInterval interval = 1002343.5432542;
NSInteger time = round(interval);
//time is now equal to 1002344

I suspect that NSTimeInterval values from NSDate would overflow an NSInteger. You'd likely want a long long. (64 bit integer.) Those can store honking-big integer values (-2^63 to 2^63 -1)

long long integerSeconds = round([NSDate timeIntervalSinceReferenceDate]);

EDIT:

It looks like an NSInteger CAN store an NSTimeInterval, at least for the next couple of decades. The current date's timeIntervalSinceReferenceDate is about 519,600,000, or about 2^28. On a 32 bit device, and NSInteger can hold a value from -2^31 to 2^31-1. (2^31 is 2,147,483,648

In Swift 3.0

let timestamp = round(NSDate().timeIntervalSince1970)

According to the documentation, NSTimeInterval is just a double:

typedef double NSTimeInterval;

You can cast this to an int:

seconds = (int) myTimeInterval;

Watch out for overflows, though!