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Time::JulianDay(3pm) User Contributed Perl Documentation Time::JulianDay(3pm)
NAME
Time::JulianDay -- Julian calendar manipulations
SYNOPSIS
use Time::JulianDay
$jd = julian_day($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)
print (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[$dow];
$seconds_since_jan_1_1970 = jd_secondslocal($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)
DESCRIPTION
JulianDay is a package that manipulates dates as number of days since some time a long
time ago. It's 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.
ERRATA
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. I'm 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.
GENESIS
Written by David Muir Sharnoff <cpan AT dave.org> with help from previous work by
Kurt Jaeger aka PI <zrzr0111 AT helpdesk.de>
based on postings from: Ian Miller <ian_m AT cix.uk>; Gary Puckering
<garyp%cognos.uucp AT uunet.net> based on Collected Algorithms of the ACM ?; and the
unknown-to-me author of Time::Local.
LICENSE
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
cpan AT dave.org.
perl v5.28.1 2019-01-23 Time::JulianDay(3pm)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2025-02-22 09:01 @3.15.205.161 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)