[LEAPSECS] Lets get REAL about time.
seaman at noao.edu
Sat Jan 21 13:21:15 EST 2012
Poul-Henning Kamp wrote:
> Rob Seaman writes:
>> Testing for equality of timestamps?
> I would hope that using a FP format and mandate that for runtime
> you never get two which are the same, should eliminate that hobby.
> I don't know any valid usecase for testing timestamps for validity,
> except for testing for programming errors.
Timestamps are preserved in various data structures for instance as identifiers. Two such may need to be compared. If the full 128 bits are preserved these will serve as well as any other unencrypted hash, but until the layer above this is designed it isn't clear exactly how the base library will be used. Timestamps may also originate on different hosts, slaved to much less precisely than the Planck time, Bohr radius or "QED events" by NTP or what have you. Two such from two different hosts may need to be compared for proximity / equality. A library method(s) for doing so is desirable so that it isn't reinvented for each application with different epsilons, open/closed interval ambiguities, etc.
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