calendar-cursor-to-date is a compiled Lisp function in `calendar.el'.

(calendar-cursor-to-date &optional ERROR EVENT)

Return a list (month day year) of current cursor position.
If cursor is not on a specific date, signals an error if optional parameter
ERROR is non-nil, otherwise just returns nil.
If EVENT is non-nil, it's an event indicating the buffer position to
use instead of point.