bug#25469: 26.0.50; Document lock files

bug#25469: 26.0.50; Document lock files

[Philipp Stephani]

There is no documentation at all about the format used by lock file
names in either the Emacs or the Elisp manual: the indexes don't contain
an entry for .#, and neither manual documents the format.  Given that
these files are highly visible, I think their format should be
documented.


In GNU Emacs 26.0.50.36 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2017-01-17 built on localhost
Repository revision: fd8196503247a4577a422475c6b8552b0ef4068e
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description:	Ubuntu 14.04 LTS

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --with-modules --enable-checking
 --enable-check-lisp-object-type 'CFLAGS=-ggdb3 -O0''

Configured features:
XPM JPEG TIFF GIF PNG SOUND GSETTINGS NOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message subr-x puny seq byte-opt gv
bytecomp byte-compile cl-extra help-mode cconv cl-loaddefs pcase cl-lib
dired dired-loaddefs format-spec rfc822 mml easymenu mml-sec
password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript case-table epa-hook jka-cmpr-hook help
simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs button
faces cus-face macroexp files text-properties overlay sha1 md5 base64
format env code-pages mule custom widget hashtable-print-readable
backquote inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 97710 9873)
 (symbols 48 20220 1)
 (miscs 40 331 131)
 (strings 32 18024 4513)
 (string-bytes 1 592997)
 (vectors 16 14090)
 (vector-slots 8 472904 5556)
 (floats 8 181 33)
 (intervals 56 218 0)
 (buffers 976 12)
 (heap 1024 37427 902))

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bug#25469: 26.0.50; Document lock files

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Tue, 17 Jan 2017 20:41:35 +0100
> 
> 
> There is no documentation at all about the format used by lock file
> names in either the Emacs or the Elisp manual: the indexes don't contain
> an entry for .#, and neither manual documents the format.  Given that
> these files are highly visible, I think their format should be
> documented.

I'm not sure I agree.  The format is an internal implementation
detail, and in fact we've changed it recently to solve an obscure bug.
Neither users nor Lisp programmers need to be aware of the format, and
if they are really curious, they can look in the C sources.

bug#25469: 26.0.50; Document lock files

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > I'm not sure I agree.  The format is an internal implementation
  > detail, and in fact we've changed it recently to solve an obscure bug.
  > Neither users nor Lisp programmers need to be aware of the format, and
  > if they are really curious, they can look in the C sources.

I agree.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.