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From: Zefram <zefram@fysh.org>
To: 26329@debbugs.gnu.org
Subject: bug#26329: monotonic time not supplied by current-time
Date: Sat, 1 Apr 2017 12:18:38 +0100	[thread overview]
Message-ID: <20170401111838.GW6453@fysh.org> (raw)

The SRFI-19 current-time function can return several flavours of the
current time:

scheme@(guile-user)> (use-modules (srfi srfi-19))
scheme@(guile-user)> (current-time time-utc)
$1 = #<time type: time-utc nanosecond: 727666000 second: 1491045256>
scheme@(guile-user)> (current-time time-tai)
$2 = #<time type: time-tai nanosecond: 414752000 second: 1491045294>
scheme@(guile-user)> (current-time time-monotonic)
$3 = #<time type: time-tai nanosecond: 814494000 second: 1491045297>

The last of these three is erroneous: a time structure of type
time-monotonic was requested and must be returned, but instead the
type is time-tai.  Although the implementation gives these two time
types numerically identical behaviour, it does treat them as nominally
distinct in other operations:

scheme@(guile-user)> (eqv? time-tai time-monotonic)
$4 = #f
scheme@(guile-user)> (julian-day->time-tai 2450000)
$5 = #<time type: time-tai nanosecond: 0 second: 813240029>
scheme@(guile-user)> (julian-day->time-monotonic 2450000)
$6 = #<time type: time-monotonic nanosecond: 0 second: 813240029>

-zefram





             reply	other threads:[~2017-04-01 11:18 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-01 11:18 Zefram [this message]
2017-04-19 13:10 ` bug#26329: monotonic time not supplied by current-time Andy Wingo

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