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List:       gpsd-dev
Subject:    Re: [gpsd-dev] attitude_t.mtime
From:       "Gary E. Miller" <gem () rellim ! com>
Date:       2018-09-27 21:51:48
Message-ID: 20180927145148.6ad54a29 () spidey ! rellim ! com
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Yo Peter!

On Thu, 27 Sep 2018 20:59:19 +0000 (GMT)
Peter Liu <greendice@me.com> wrote:

> You added attitude_t.mtime in gps.h as timespec. Unless there is some
> special reasons, could we use timestamp_t instead?

There has been a long term plan to move all timestamp_t to timespec.

timespec keeps time to the nanosecond.

timestamp_t is just a double.

As a comment in gps.h notes:

/* WARNING!  potential loss of precision in timestamp_t
 * a double is 53 significant bits.
 * UNIX time to nanoSec precision is 62 significant bits
 * UNIX time to nanoSec precision after 2038 is 63 bits
 * timestamp_t is only microSec precision
 * timestamp_t and PPS do not play well together
 */

So all new time will be timespe.  All existing timestamps will become
timespec in gpsd 3.19.

No need to fear the conversion.  It is a good thing.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem@rellim.com  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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