PHP 5 Calendar Functions

PHP Calendar Introduction

The calendar extension contains functions that simplifies converting between different calendar formats.

It is based on the Julian Day Count, which is a count of days starting from January 1st, 4713 B.C.

Note: To convert between calendar formats, you must first convert to Julian Day Count, then to the calendar of your choice.

Note: The Julian Day Count is not the same as the Julian Calendar!

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Installation

For these functions to work, you have to compile PHP with --enable-calendar.

The Windows version of PHP has built-in support for this extension.

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PHP 5 Calendar Functions

Function	Description
cal_days_in_month()	Returns the number of days in a month for a specified year and calendar
cal_from_jd()	Converts a Julian Day Count into a date of a specified calendar
cal_info()	Returns information about a specified calendar
cal_to_jd()	Converts a date in a specified calendar to Julian Day Count
easter_date()	Returns the Unix timestamp for midnight on Easter of a specified year
easter_days()	Returns the number of days after March 21, that the Easter Day is in a specified year
frenchtojd()	Converts a French Republican date to a Julian Day Count
gregoriantojd()	Converts a Gregorian date to a Julian Day Count
jddayofweek()	Returns the day of the week
jdmonthname()	Returns a month name
jdtofrench()	Converts a Julian Day Count to a French Republican date
jdtogregorian()	Converts a Julian Day Count to a Gregorian date
jdtojewish()	Converts a Julian Day Count to a Jewish date
jdtojulian()	Converts a Julian Day Count to a Julian date
jdtounix()	Converts Julian Day Count to Unix timestamp
jewishtojd()	Converts a Jewish date to a Julian Day Count
juliantojd()	Converts a Julian date to a Julian Day Count
unixtojd()	Converts Unix timestamp to Julian Day Count

PHP 5 Predefined Calendar Constants

Constant	Type	PHP Version
CAL_GREGORIAN	Integer	PHP 4
CAL_JULIAN	Integer	PHP 4
CAL_JEWISH	Integer	PHP 4
CAL_FRENCH	Integer	PHP 4
CAL_NUM_CALS	Integer	PHP 4
CAL_DOW_DAYNO	Integer	PHP 4
CAL_DOW_SHORT	Integer	PHP 4
CAL_DOW_LONG	Integer	PHP 4
CAL_MONTH_GREGORIAN_SHORT	Integer	PHP 4
CAL_MONTH_GREGORIAN_LONG	Integer	PHP 4
CAL_MONTH_JULIAN_SHORT	Integer	PHP 4
CAL_MONTH_JULIAN_LONG	Integer	PHP 4
CAL_MONTH_JEWISH	Integer	PHP 4
CAL_MONTH_FRENCH	Integer	PHP 4
CAL_EASTER_DEFAULT	Integer	PHP 4.3
CAL_EASTER_ROMAN	Integer	PHP 4.3
CAL_EASTER_ALWAYS_GREGORIAN	Integer	PHP 4.3
CAL_EASTER_ALWAYS_JULIAN	Integer	PHP 4.3
CAL_JEWISH_ADD_ALAFIM_GERESH	Integer	PHP 5.0
CAL_JEWISH_ADD_ALAFIM	Integer	PHP 5.0
CAL_JEWISH_ADD_GERESHAYIM	Integer	PHP 5.0

Credit: www.w3schools.com