master 316cc91: Improve documentation of 'set-keyboard-coding-system'

[Eli Zaretskii]

branch: master
commit 316cc9152faee7577e158f7caf26ce4c9cd5371a
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Improve documentation of 'set-keyboard-coding-system'
    
    * doc/lispref/nonascii.texi (Terminal I/O Encoding):
    * doc/emacs/mule.texi (Terminal Coding):
    * lisp/international/mule.el (set-keyboard-coding-system):
    Document that 'set-keyboard-coding-system' has no effect on modern
    MS-Windows systems.  (Bug#15289)
---
 doc/emacs/mule.texi        | 6 ++++++
 doc/lispref/nonascii.texi  | 4 +++-
 lisp/international/mule.el | 7 +++++--
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/doc/emacs/mule.texi b/doc/emacs/mule.texi
index 22b3677..81aabfb 100644
--- a/doc/emacs/mule.texi
+++ b/doc/emacs/mule.texi
@@ -1330,6 +1330,12 @@ You can do this by putting
 @noindent
 in your init file.
 
+@findex w32-set-console-codepage
+  Setting @code{keyboard-coding-system} has no effect on MS-Windows,
+except on old Windows 9X systems, in which case the encoding must
+match the current codepage of the MS-Windows console, which can be
+changed by calling @code{w32-set-console-codepage}.
+
   There is a similarity between using a coding system translation for
 keyboard input, and using an input method: both define sequences of
 keyboard input that translate into single characters.  However, input
diff --git a/doc/lispref/nonascii.texi b/doc/lispref/nonascii.texi
index c22930d..0cc2b7e 100644
--- a/doc/lispref/nonascii.texi
+++ b/doc/lispref/nonascii.texi
@@ -1988,7 +1988,9 @@ for decoding keyboard input from @var{terminal}.  If
 @var{coding-system} is @code{nil}, that means not to decode keyboard
 input.  If @var{terminal} is a frame, it means that frame's terminal;
 if it is @code{nil}, that means the currently selected frame's
-terminal.  @xref{Multiple Terminals}.
+terminal.  @xref{Multiple Terminals}.  Note that on modern MS-Windows
+systems Emacs always uses Unicode input when decoding keyboard input,
+so the encoding set by this command has no effect on Windows.
 @end deffn
 
 @defun terminal-coding-system &optional terminal
diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index 9cd38af..1a53237 100644
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -1380,8 +1380,11 @@ If CODING-SYSTEM is nil or the coding-type of 
CODING-SYSTEM is
 `raw-text', the decoding of keyboard input is disabled.
 
 TERMINAL may be a terminal object, a frame, or nil for the
-selected frame's terminal.  The setting has no effect on
-graphical terminals."
+selected frame's terminal.
+
+The setting has no effect on graphical terminals.  It also
+has no effect on MS-Windows text-mode terminals, except on
+Windows 9X systems.  For Windows 9X, see also `w32-set-console-codepage'."
   (interactive
    (list (let* ((coding (keyboard-coding-system nil))
                (default (if (eq (coding-system-type coding) 'raw-text)