Function: date-days-in-month

date-days-in-month is a byte-compiled function defined in time-date.el.gz.

Signature

(date-days-in-month YEAR MONTH)

Documentation

The number of days in MONTH in YEAR.

View in manual

Probably introduced at or before Emacs version 27.1.

Source Code

;; Defined in /usr/src/emacs/lisp/calendar/time-date.el.gz
(defun date-days-in-month (year month)
  "The number of days in MONTH in YEAR."
  (unless (and (numberp month) (<= 1 month 12))
    (error "Month %s is invalid" month))
  (if (= month 2)
      (if (date-leap-year-p year)
          29
        28)
    (if (memq month '(1 3 5 7 8 10 12))
        31
      30)))