Login or Register to Ask a Question and Join Our Community

Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

time::julianday(3pm) [debian man page]

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@dave.sharnoff.org> with help from previous work by Kurt Jaeger aka PI
       <zrzr0111@helpdesk.rus.uni-stuttgart.de>
	    based on postings from: Ian Miller <ian_m@cix.compulink.co.uk>; Gary Puckering <garyp%cognos.uucp@uunet.uu.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@dave.sharnoff.org.

perl v5.12.3							    2011-05-06						      Time::JulianDay(3pm)

Check Out this Related Man Page

Time::gmtime(3pm)					 Perl Programmers Reference Guide					 Time::gmtime(3pm)

NAME

       Time::gmtime - by-name interface to Perl's built-in gmtime() function

SYNOPSIS

	use Time::gmtime;
	$gm = gmtime();
	printf "The day in Greenwich is %s
",
	   (qw(Sun Mon Tue Wed Thu Fri Sat Sun))[ $gm->wday() ];

	use Time::gmtime qw(:FIELDS);
	gmtime();
	printf "The day in Greenwich is %s
",
	   (qw(Sun Mon Tue Wed Thu Fri Sat Sun))[ $tm_wday ];

	$now = gmctime();

	use Time::gmtime;
	use File::stat;
	$date_string = gmctime(stat($file)->mtime);

DESCRIPTION

       This module's default exports override the core gmtime() function, replacing it with a version that returns "Time::tm" objects.	This
       object has methods that return the similarly named structure field name from the C's tm structure from time.h; namely sec, min, hour, mday,
       mon, year, wday, yday, and isdst.

       You may also import all the structure fields directly into your namespace as regular variables using the :FIELDS import tag.  (Note that
       this still overrides your core functions.)  Access these fields as variables named with a preceding "tm_" in front their method names.
       Thus, "$tm_obj->mday()" corresponds to $tm_mday if you import the fields.

       The gmctime() function provides a way of getting at the scalar sense of the original CORE::gmtime() function.

       To access this functionality without the core overrides, pass the "use" an empty import list, and then access function functions with their
       full qualified names.  On the other hand, the built-ins are still available via the "CORE::" pseudo-package.

NOTE

       While this class is currently implemented using the Class::Struct module to build a struct-like class, you shouldn't rely upon this.

AUTHOR

       Tom Christiansen

perl v5.18.2							    2013-11-04							 Time::gmtime(3pm)
Man Page