Manual Reference Pages - TIME::JULIANDAY (3)
Time::JulianDay -- Julian calendar manipulations
$jd = julian_day($year, $month_1_to_12, $day)
$jd = local_julian_day($seconds_since_1970);
$jd = gm_julian_day($seconds_since_1970);
($year, $month_1_to_12, $day) = inverse_julian_day($jd)
$dow = day_of_week($jd)
$seconds_since_jan_1_1970 = jd_secondslocal($jd, $hour, $min, $sec)
$seconds_since_jan_1_1970 = jd_secondsgm($jd, $hour, $min, $sec)
$seconds_since_jan_1_1970 = jd_timelocal($sec,$min,$hours,$mday,$month_0_to_11,$year)
$seconds_since_jan_1_1970 = jd_timegm($sec,$min,$hours,$mday,$month_0_to_11,$year)
JulianDay is a package that manipulates dates as number of days since
some time a long time ago. Its easy to add and subtract time
using julian days...
The day_of_week returned by day_of_week() is 0 for Sunday, and 6 for
Saturday and everything else is in between.
Time::JulianDay is not a correct implementation. There are two
problems. The first problem is that Time::JulianDay only works
with integers. Julian Day can be fractional to represent time
within a day. If you call inverse_julian_day() with a non-integer
time, it will often give you an incorrect result.
The second problem is that Julian Days start at noon rather than
midnight. The julian_day() function returns results that are too
large by 0.5.
What to do about these problems is currently open for debate. Im
tempted to leave the current functions alone and add a second set
with more accurate behavior.
There is another implementation in Astro::Time that may be more accurate.
Written by David Muir Sharnoff <firstname.lastname@example.org> with help from
previous work by
Kurt Jaeger aka PI <email@example.com>
based on postings from: Ian Miller <firstname.lastname@example.org>;
Gary Puckering <email@example.com>
based on Collected Algorithms of the ACM ?;
and the unknown-to-me author of Time::Local.
Copyright (C) 1996-1999 David Muir Sharnoff. License hereby
granted for anyone to use, modify or redistribute this module at
their own risk. Please feed useful changes back to firstname.lastname@example.org.
|perl v5.20.3 ||TIME::JULIANDAY (3) ||2011-05-06 |
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