PHP Calendar Functions

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PHP Calendar Introduction

The calendar functions are useful when working with different calendar formats. The standard it is based on is the Julian day count (Julian day count is a count of days starting from January 1, 4713 B.C.). Note that the Julian day count is not the same as the Julian calendar!
Note: To convert between calendar formats, you must first convert to Julian day count, then to the calendar format.

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Installation

The windows version of PHP has built-in support for the calendar extension. So, the calendar functions will work automatically.
However, if you are running the Linux version of PHP, you will have to compile PHP with --enable-calendar to get the calendar functions to work.

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PHP Calendar Functions

PHP: indicates the earliest version of PHP that supports the function.

Function	Description	PHP
cal_days_in_month()	Returns the number of days in a month for a specified year and calendar	4
cal_from_jd()	Converts a Julian day count into a date of a specified calendar	4
cal_info()	Returns information about a given calendar	4
cal_to_jd()	Converts a date to Julian day count	4
easter_date()	Returns the Unix timestamp for midnight on Easter of a specified year	3
easter_days()	Returns the number of days after March 21, on which Easter falls for a specified year	3
FrenchToJD()	Converts a French Republican date to a Julian day count	3
GregorianToJD()	Converts a Gregorian date to a Julian day count	3
JDDayOfWeek()	Returns the day of a week	3
JDMonthName()	Returns a month name	3
JDToFrench()	Converts a Julian day count to a French Republican date	3
JDToGregorian()	Converts a Julian day count to a Gregorian date	3
jdtojewish()	Converts a Julian day count to a Jewish date	3
JDToJulian()	Converts a Julian day count to a Julian date	3
jdtounix()	Converts a Julian day count to a Unix timestamp	4
JewishToJD()	Converts a Jewish date to a Julian day count	3
JulianToJD()	Converts a Julian date to a Julian day count	3
unixtojd()	Converts a Unix timestamp to a Julian day count	4

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PHP Calendar Constants

PHP: indicates the earliest version of PHP that supports the constant.

Constant	Description	PHP
CAL_GREGORIAN	Gregorian calendar	3
CAL_JULIAN	Julian calendar	3
CAL_JEWISH	Jewish calendar	3
CAL_FRENCH	French Republican calendar	3
CAL_NUM_CALS		3
CAL_DOW_DAYNO		3
CAL_DOW_SHORT		3
CAL_DOW_LONG		3
CAL_MONTH_GREGORIAN_SHORT		3
CAL_MONTH_GREGORIAN_LONG		3
CAL_MONTH_JULIAN_SHORT		3
CAL_MONTH_JULIAN_LONG		3
CAL_MONTH_JEWISH		3
CAL_MONTH_FRENCH		3
CAL_EASTER_DEFAULT		4
CAL_EASTER_DEFAULT		4
CAL_EASTER_ROMAN		4
CAL_EASTER_ALWAYS_GREGORIAN		4
CAL_EASTER_ALWAYS_JULIAN		4
CAL_JEWISH_ADD_ALAFIM_GERESH		5
CAL_JEWISH_ADD_ALAFIM		5
CAL_JEWISH_ADD_GERESHAYIM		5

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