New FAQ about Ctrl keys on xterm

* doc/misc/efaq.texi
(Some Ctrl-modified keys do not work on xterm): New section
(bug#73813).

(cherry picked from commit a61bf74225737a7c87b95d604b6e8c2ce9686296)

diff --git a/doc/misc/efaq.texi b/doc/misc/efaq.texi
index 4df091dbeaca58d8164eca789da7f117c99e7e8c..714fd38e4265b27d36657eec64d0710f5c6af499 100644 (file)
--- a/doc/misc/efaq.texi
+++ b/doc/misc/efaq.texi
@@ -4056,6 +4056,7 @@ information is available from
 * Compose Character::
 * Binding combinations of modifiers and function keys::
 * Meta key does not work in xterm::
+* Some Ctrl-modified keys do not work on xterm::
 @end menu
 
 @node Binding keys to commands
@@ -4527,6 +4528,25 @@ You might have to replace @samp{Meta} with @samp{Alt}.
 
 @end itemize
 
+@node Some Ctrl-modified keys do not work on xterm
+@section Why don't some keys like @kbd{C-.} work on xterm?
+
+If your @code{xterm} version is 216 or newer, you should have keys like
+@kbd{C-.} and @kbd{C-,} if you add the following resource specification
+to your @file{~/.Xdefaults}:
+
+@example
+ XTerm.VT100.modifyOtherKeys: 1
+@end example
+
+@noindent
+If you want to use @code{uxterm}, also add the following:
+
+@example
+ UXTerm.VT100.modifyOtherKeys: 1
+@end example
+
+
 @c ------------------------------------------------------------
 @node Alternate character sets
 @chapter Alternate character sets