1;;; flow-ctrl.el --- help for lusers on cu(1) or ttys with wired-in ^S/^Q flow control 2 3;; Copyright (C) 1990, 1991, 1994, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author Kevin Gallagher 7;; Maintainer: FSF 8;; Adapted-By: ESR 9;; Keywords: hardware 10 11;; This file is part of GNU Emacs. 12 13;; GNU Emacs is free software; you can redistribute it and/or modify 14;; it under the terms of the GNU General Public License as published by 15;; the Free Software Foundation; either version 2, or (at your option) 16;; any later version. 17 18;; GNU Emacs is distributed in the hope that it will be useful, 19;; but WITHOUT ANY WARRANTY; without even the implied warranty of 20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21;; GNU General Public License for more details. 22 23;; You should have received a copy of the GNU General Public License 24;; along with GNU Emacs; see the file COPYING. If not, write to the 25;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 26;; Boston, MA 02110-1301, USA. 27 28;;; Commentary: 29 30;; Terminals that use XON/XOFF flow control can cause problems with 31;; GNU Emacs users. This file contains Emacs Lisp code that makes it 32;; easy for a user to deal with this problem, when using such a 33;; terminal. 34;; 35;; To invoke these adjustments, a user need only invoke the function 36;; enable-flow-control-on with a list of terminal types in his/her own 37;; .emacs file. As arguments, give it the names of one or more terminal 38;; types in use by that user which require flow control adjustments. 39;; Here's an example: 40;; 41;; (enable-flow-control-on "vt200" "vt300" "vt101" "vt131") 42 43;; Portability note: This uses (getenv "TERM"), and therefore probably 44;; won't work outside of UNIX-like environments. 45 46;;; Code: 47 48(defvar flow-control-c-s-replacement ?\034 49 "Character that replaces C-s, when flow control handling is enabled.") 50(defvar flow-control-c-q-replacement ?\036 51 "Character that replaces C-q, when flow control handling is enabled.") 52 53(put 'keyboard-translate-table 'char-table-extra-slots 0) 54 55;;;###autoload 56(defun enable-flow-control (&optional argument) 57 "Toggle flow control handling. 58When handling is enabled, user can type C-s as C-\\, and C-q as C-^. 59With arg, enable flow control mode if arg is positive, otherwise disable." 60 (interactive "P") 61 (if (if argument 62 ;; Argument means enable if arg is positive. 63 (<= (prefix-numeric-value argument) 0) 64 ;; No arg means toggle. 65 (nth 1 (current-input-mode))) 66 (progn 67 ;; Turn flow control off, and stop exchanging chars. 68 (set-input-mode t nil (nth 2 (current-input-mode))) 69 (if keyboard-translate-table 70 (progn 71 (aset keyboard-translate-table flow-control-c-s-replacement nil) 72 (aset keyboard-translate-table ?\^s nil) 73 (aset keyboard-translate-table flow-control-c-q-replacement nil) 74 (aset keyboard-translate-table ?\^q nil)))) 75 ;; Turn flow control on. 76 ;; Tell emacs to pass C-s and C-q to OS. 77 (set-input-mode nil t (nth 2 (current-input-mode))) 78 ;; Initialize translate table, saving previous mappings, if any. 79 (cond ((null keyboard-translate-table) 80 (setq keyboard-translate-table 81 (make-char-table 'keyboard-translate-table nil))) 82 ((char-table-p keyboard-translate-table) 83 (setq keyboard-translate-table 84 (copy-sequence keyboard-translate-table))) 85 (t 86 (let ((the-table (make-char-table 'keyboard-translate-table nil))) 87 (let ((i 0) 88 (j (length keyboard-translate-table))) 89 (while (< i j) 90 (aset the-table i (elt keyboard-translate-table i)) 91 (setq i (1+ i)))) 92 (setq keyboard-translate-table the-table)))) 93 ;; Swap C-s and C-\ 94 (aset keyboard-translate-table flow-control-c-s-replacement ?\^s) 95 (aset keyboard-translate-table ?\^s flow-control-c-s-replacement) 96 ;; Swap C-q and C-^ 97 (aset keyboard-translate-table flow-control-c-q-replacement ?\^q) 98 (aset keyboard-translate-table ?\^q flow-control-c-q-replacement) 99 (message "XON/XOFF adjustment for %s: use %s for C-s, and use %s for C-q" 100 (getenv "TERM") 101 (single-key-description flow-control-c-s-replacement) 102 (single-key-description flow-control-c-q-replacement)) 103 (sleep-for 2))) ; Give user a chance to see message. 104 105;;;###autoload 106(defun enable-flow-control-on (&rest losing-terminal-types) 107 "Enable flow control if using one of a specified set of terminal types. 108Use `(enable-flow-control-on \"vt100\" \"h19\")' to enable flow control 109on VT-100 and H19 terminals. When flow control is enabled, 110you must type C-\\ to get the effect of a C-s, and type C-^ 111to get the effect of a C-q." 112 (let ((term (getenv "TERM")) 113 hyphend) 114 ;; Look for TERM in LOSING-TERMINAL-TYPES. 115 ;; If we don't find it literally, try stripping off words 116 ;; from the end, one by one. 117 (while (and term (not (member term losing-terminal-types))) 118 ;; Strip off last hyphen and what follows, then try again. 119 (if (setq hyphend (string-match "[-_][^-_]+$" term)) 120 (setq term (substring term 0 hyphend)) 121 (setq term nil))) 122 (if term 123 (enable-flow-control)))) 124 125(provide 'flow-ctrl) 126 127;;; arch-tag: 0eb7b19e-0d93-4e0b-9ea2-72b574076a56 128;;; flow-ctrl.el ends here 129