POSIXTime -package:tztime -package:time

POSIX time is the nominal time since 1970-01-01 00:00 UTC To convert from a CTime or System.Posix.EpochTime, use realToFrac.
The nominal (ignoring leap seconds) time difference since midnight 1970-01-01, the Unix epoch. Equvialent to a normalised struct timeval.
Control.Lens.Iso between UTCTime and POSIXTime.
> getPOSIXTime
1459515013.527711s
> review posixTime <$> getPOSIXTime
2016-01-01 12:50:45.588729 UTC
Convert POSIXTime to Time.
Get the POSIX time. If SOURCE_DATE_EPOCH is set to a unix time, it is used instead of the current time.
Time as seconds since midnight Jan 1 1970 UTC. Integer rendering as for SqlDiffTime.
realToFrac of Clock.Posix.getPOSIXTime
get_ct = getCurrentTimeAsPosix
get_pt = getPosixTimeAsPosix
(ct,pt) <- get_ct >>= \t0 -> get_pt >>= \t1 -> return (t0,t1)
print (pt - ct,pt - ct < 1e-5)
Convert Time to POSIXTime.
Get the current POSIX time from the system clock.
Return the current system POSIX time via gettimeofday, or getSystemTimeAsFileTime on Windows. See also getCurrentTime, getZonedTime.
Parse either a POSIX timestamp or RFC3339 formatted timestamp as POSIXTime.