cal_to_jd: Getting Julian Day count from a supported date

$day = cal_to_jd(CAL_GREGORIAN,2,2,2103);
echo $day;

The output is 2489197

Syntax

cal_to_jd('calendar', month, day , year )

In the above code the list of calendar are CAL_GREGORIAN, CAL_JULIAN, CAL_JEWISH and CAL_FRENCH.

Example: Converting Gregorian Date to Julian Day

$jd = cal_to_jd(CAL_GREGORIAN, 10, 8, 2023);
echo "Julian Day: " . $jd;  // Output: Julian Day: 2460219

Example: Handling Out-of-Range Dates

$jd = cal_to_jd(CAL_GREGORIAN, 15, 50, 2023);
if ($jd === false) {
    echo "Invalid date provided!";
}

These examples focus on converting dates from various calendars and handling invalid inputs.
Read how cal_to_jd function is used to get weekday
Demo of how Unix timestamp is used to generate Julian Day and Calendar
Calendar Functions

Subhendu Mohapatra

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cal_to_jd: getting Julian day count

Example: Converting Gregorian Date to Julian Day

Example: Handling Out-of-Range Dates

Subhendu Mohapatra