Variable: float-pi

float-pi is a variable defined in float-sup.el.gz.

Value

3.141592653589793

Documentation

The value of Pi (3.1415926...).

View in manual

Probably introduced at or before Emacs version 23.3.

Source Code

;; Defined in /usr/src/emacs/lisp/emacs-lisp/float-sup.el.gz
;;; float-sup.el --- define some constants useful for floating point numbers.  -*- lexical-binding:t -*-

;; Copyright (C) 1985-1987, 2001-2025 Free Software Foundation, Inc.

;; Maintainer: emacs-devel@gnu.org
;; Keywords: internal
;; Package: emacs

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

;; Define pi and e via math-lib calls (much less prone to killer typos).
(defconst float-pi (* 4 (atan 1)) "The value of Pi (3.1415926...).")