documentation: update CodingStyle tips for Emacs users
Describe a setup that integrates better with Emacs' cc-mode and also fixes
up the alignment of continuation lines to really only use tabs.
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index 6caa146..1875e50 100644
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -474,25 +474,29 @@
So, you can either get rid of GNU emacs, or change it to use saner
values. To do the latter, you can stick the following in your .emacs file:
-(defun linux-c-mode ()
- "C mode with adjusted defaults for use with the Linux kernel."
- (interactive)
- (c-mode)
- (c-set-style "K&R")
- (setq tab-width 8)
- (setq indent-tabs-mode t)
- (setq c-basic-offset 8))
+(defun c-lineup-arglist-tabs-only (ignored)
+ "Line up argument lists by tabs, not spaces"
+ (let* ((anchor (c-langelem-pos c-syntactic-element))
+ (column (c-langelem-2nd-pos c-syntactic-element))
+ (offset (- (1+ column) anchor))
+ (steps (floor offset c-basic-offset)))
+ (* (max steps 1)
+ c-basic-offset)))
-This will define the M-x linux-c-mode command. When hacking on a
-module, if you put the string -*- linux-c -*- somewhere on the first
-two lines, this mode will be automatically invoked. Also, you may want
-to add
+(add-hook 'c-mode-hook
+ (lambda ()
+ (let ((filename (buffer-file-name)))
+ ;; Enable kernel mode for the appropriate files
+ (when (and filename
+ (string-match "~/src/linux-trees" filename))
+ (setq indent-tabs-mode t)
+ (c-set-style "linux")
+ (c-set-offset 'arglist-cont-nonempty
+ '(c-lineup-gcc-asm-reg
+ c-lineup-arglist-tabs-only))))))
-(setq auto-mode-alist (cons '("/usr/src/linux.*/.*\\.[ch]$" . linux-c-mode)
- auto-mode-alist))
-
-to your .emacs file if you want to have linux-c-mode switched on
-automagically when you edit source files under /usr/src/linux.
+This will make emacs go better with the kernel coding style for C
+files below ~/src/linux-trees.
But even if you fail in getting emacs to do sane formatting, not
everything is lost: use "indent".