Article View: comp.std.c
Article #2185Re: Change to time() fn?
From: Graham Stoney
Date: Fri, 02 Oct 1992 02:34
Date: Fri, 02 Oct 1992 02:34
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alpha@waggen.twuug.com (Joe Wright) writes: >Please remember that floats (and doubles) are approximates. >The value of time_t must be precise. We don't like a value >which says 'it's almost 5 o'clock'. Precision requires >time_t to be an integer. But time is a continuum; it is not discrete. Integers, floats and doubles all store discrete values, so none of them can precisely represent all values of time, not even in a small fixed interval. You may not like a value that says "it's about 5 oclock", but that's the best we can do. A floating point time_t will allow finer resolution for times near the epoch than an integral one, and less resolution for times far from the epoch. An integral time_t abruptly becomes unable to represent the time at all as you move away from the epoch, whereas the precision of the floating point time_t degrades gracefully. Since we are normally more interested in times near the present than the distant past or future, this is a reasonable tradeoff. I think this was the original poster's point. regards, Graham
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Newsgroups: comp.std.c Path: arc1-ca.pugleaf.net!sparky!uunet!munnari.oz.au!metro!mama!greyham From: greyham@research.canon.oz.au (Graham Stoney) Subject: Re: Change to time() fn? Message-ID: <BvH368.KA9@research.canon.oz.au> Sender: news@research.canon.oz.au Organization: Canon Information Systems Research Australia References: <1992Sep29.154252.5453@ima.isc.com> <1992Sep30.034813.2589@waggen.twuug.com> Date: Fri, 2 Oct 1992 02:34:55 GMT Lines: 20