(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
cal_to_jd — Converts from a supported calendar to Julian Day Count
$calendar,$month,$day,$year
cal_to_jd() calculates the Julian day count
for a date in the specified calendar.
Supported calendars are
CAL_GREGORIAN,
CAL_JULIAN,
CAL_JEWISH and
CAL_FRENCH.
calendar
Calendar to convert from, one of
CAL_GREGORIAN,
CAL_JULIAN,
CAL_JEWISH or
CAL_FRENCH.
month
The month as a number, the valid range depends
on the calendar
day
The day as a number, the valid range depends
on the calendar
year
The year as a number, the valid range depends
on the calendar
A Julian Day number.