easter_date(3) [php man page]
EASTER_DATE(3) 1 EASTER_DATE(3) easter_date - Get Unix timestamp for midnight on Easter of a given year SYNOPSIS
int easter_date ([int $year = date("Y")]) DESCRIPTION
Returns the Unix timestamp corresponding to midnight on Easter of the given year. Warning This function will generate a warning if the year is outside of the range for Unix timestamps (i.e. before 1970 or after 2037). The date of Easter Day was defined by the Council of Nicaea in AD325 as the Sunday after the first full moon which falls on or after the Spring Equinox. The Equinox is assumed to always fall on 21st March, so the calculation reduces to determining the date of the full moon and the date of the following Sunday. The algorithm used here was introduced around the year 532 by Dionysius Exiguus. Under the Julian Calendar (for years before 1753) a simple 19-year cycle is used to track the phases of the Moon. Under the Gregorian Calendar (for years after 1753 - devised by Clavius and Lilius, and introduced by Pope Gregory XIII in October 1582, and into Britain and its then colonies in September 1752) two correction factors are added to make the cycle more accurate. PARAMETERS
o $year - The year as a number between 1970 an 2037. If omitted, defaults to the current year according to the local time. RETURN VALUES
The easter date as a unix timestamp. EXAMPLES
Example #1 easter_date(3) example <?php echo date("M-d-Y", easter_date(1999)); // Apr-04-1999 echo date("M-d-Y", easter_date(2000)); // Apr-23-2000 echo date("M-d-Y", easter_date(2001)); // Apr-15-2001 ?> NOTES
Note easter_date(3) relies on your system's C library time functions, rather than using PHP's internal date and time functions. As a con- sequence, easter_date(3) uses the TZ environment variable to determine the time zone it should operate in, rather than using PHP's default time zone, which may result in unexpected behaviour when using this function in conjunction with other date functions in PHP. As a workaround, you can use the easter_days(3) with DateTime and DateInterval to calculate the start of Easter in your PHP time zone as follows: <?php function get_easter_datetime($year) { $base = new DateTime("$year-03-21"); $days = easter_days($year); return $base->add(new DateInterval("P{$days}D")); } foreach (range(2012, 2015) as $year) { printf("Easter in %d is on %s ", $year, get_easter_datetime($year)->format('F j')); } ?> The above example will output: Easter in 2012 is on April 8 Easter in 2013 is on March 31 Easter in 2014 is on April 20 Easter in 2015 is on April 5 SEE ALSO
easter_days(3) for calculating Easter before 1970 or after 2037 . PHP Documentation Group EASTER_DATE(3)
Check Out this Related Man Page
CAL(1) BSD General Commands Manual CAL(1) NAME
cal, ncal -- displays a calendar and the date of Easter SYNOPSIS
cal [-3hjy] [-A number] [-B number] [[month] year] cal [-3hj] [-A number] [-B number] -m month [year] ncal [-3hjJpwy] [-A number] [-B number] [-s country_code] [[month] year] ncal [-3hJeo] [-A number] [-B number] [year] ncal [-CN] [-H yyyy-mm-dd] [-d yyyy-mm] DESCRIPTION
The cal utility displays a simple calendar in traditional format and ncal offers an alternative layout, more options and the date of Easter. The new format is a little cramped but it makes a year fit on a 25x80 terminal. If arguments are not specified, the current month is dis- played. The options are as follows: -h Turns off highlighting of today. -J Display Julian Calendar, if combined with the -e option, display date of Easter according to the Julian Calendar. -e Display date of Easter (for western churches). -j Display Julian days (days one-based, numbered from January 1). -m month Display the specified month. If month is specified as a decimal number, it may be followed by the letter 'f' or 'p' to indicate the following or preceding month of that number, respectively. -o Display date of Orthodox Easter (Greek and Russian Orthodox Churches). -p Print the country codes and switching days from Julian to Gregorian Calendar as they are assumed by ncal. The country code as deter- mined from the local environment is marked with an asterisk. -s country_code Assume the switch from Julian to Gregorian Calendar at the date associated with the country_code. If not specified, ncal tries to guess the switch date from the local environment or falls back to September 2, 1752. This was when Great Britain and her colonies switched to the Gregorian Calendar. -w Print the number of the week below each week column. -y Display a calendar for the specified year. -3 Display the previous, current and next month surrounding today. -A number Display the number of months after the current month. -B number Display the number of months before the current month. -C Switch to cal mode. -N Switch to ncal mode. -d yyyy-mm Use yyyy-mm as the current date (for debugging of date selection). -H yyyy-mm-dd Use yyyy-mm-dd as the current date (for debugging of highlighting). A single parameter specifies the year (1-9999) to be displayed; note the year must be fully specified: ``cal 89'' will not display a calendar for 1989. Two parameters denote the month and year; the month is either a number between 1 and 12, or a full or abbreviated name as speci- fied by the current locale. Month and year default to those of the current system clock and time zone (so ``cal -m 8'' will display a calen- dar for the month of August in the current year). Not all options can be used together. For example ``-3 -A 2 -B 3 -y -m 7'' would mean: show me the three months around the seventh month, three before that, two after that and the whole year. ncal will warn about these combinations. A year starts on January 1. Highlighting of dates is disabled if stdout is not a tty. SEE ALSO
calendar(3), strftime(3) HISTORY
A cal command appeared in Version 5 AT&T UNIX. The ncal command appeared in FreeBSD 2.2.6. AUTHORS
The ncal command and manual were written by Wolfgang Helbig <helbig@FreeBSD.org>. BUGS
The assignment of Julian-Gregorian switching dates to country codes is historically naive for many countries. Not all options are compatible and using them in different orders will give varying results. BSD
March 14, 2009 BSD