64 bit unsigned integer nanoseconds gets you out to 584 years (that's the year 2554 if you're using the Unix epoch). That's good enough for me to use universally for passing times around in the internals of my code. User input and output are going to and from that representation.
Half as many, of course, if you use a signed integer. If you don't need nanoseconds, then use microseconds and you get 292 thousand years to work with.
Integers are just a bit easier than floats for timestamps in my experience (e.g., comparing floats to one another is fraught and you'll be fighting this at every turn in your code).
Half as many, of course, if you use a signed integer. If you don't need nanoseconds, then use microseconds and you get 292 thousand years to work with.
Integers are just a bit easier than floats for timestamps in my experience (e.g., comparing floats to one another is fraught and you'll be fighting this at every turn in your code).