cal_info returns information on the specified calendar.
Calendar information is returned as an array containing the elements calname, calsymbol, month, abbrevmonth and maxdaysinmonth. The names of the different calendars which can be used as calendar are as follows:
0 or CAL_GREGORIAN - Gregorian Calendar
1 or CAL_JULIAN - Julian Calendar
2 or CAL_JEWISH - Jewish Calendar
3 or CAL_FRENCH - French Revolutionary Calendar
If no calendar is specified information on all supported calendars is returned as an array.
Calendar to return information for. If no calendar is specified information about all calendars is returned.