Function: math-std-daylight-savings

math-std-daylight-savings is a byte-compiled function defined in calc-forms.el.gz.

Signature

(math-std-daylight-savings DATE DT ZONE BUMP)

Documentation

Standard North American daylight saving algorithm.

Before 2007, this uses math-std-daylight-savings-old, where daylight saving began on the first Sunday of April at 2 a.m., and ended on the last Sunday of October at 2 a.m. As of 2007, this uses math-std-daylight-savings-new, where daylight saving begins on the second Sunday of March at 2 a.m., and ends on the first Sunday of November at 2 a.m.

Source Code

;; Defined in /usr/src/emacs/lisp/calc/calc-forms.el.gz
(defun math-std-daylight-savings (date dt zone bump)
  "Standard North American daylight saving algorithm.
Before 2007, this uses `math-std-daylight-savings-old', where
daylight saving began on the first Sunday of April at 2 a.m.,
and ended on the last Sunday of October at 2 a.m.
As of 2007, this uses `math-std-daylight-savings-new', where
daylight saving begins on the second Sunday of March at 2 a.m.,
and ends on the first Sunday of November at 2 a.m."
  (if (< (car dt) 2007)
      (math-std-daylight-savings-old date dt zone bump)
    (math-std-daylight-savings-new date dt zone bump)))