Document possible reasons for lack of colors on a tty.

1 files changed, 22 insertions, 0 deletions

diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index a1f85a4c7b7..13b4436d9c0 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -89,6 +89,28 @@ This currently doesn't work with scroll-bar widgets (and we don't know
 a good way of implementing it with widgets).  If Emacs is configured
 --without-toolkit-scroll-bars, C-mouse-2 on the scroll bar does work.
 
+* Colors are not available on a tty or in xterm.
+
+Emacs 21 supports colors on character terminals and in xterm (when
+Emacs is invoked with the `-nw' option), but this support on Unix and
+GNU/Linux systems relies on the termcap entry to specify that the
+display supports color.  Emacs looks at the "Co" capability for the
+terminal to find out how many colors are supported; it should be
+non-zero to activate the color support within Emacs.  (Most color
+terminals support 8 or 16 colors.)
+
+Emacs uses the termcap entry for the terminal whose name is the value
+of the environment variable TERM.  On an xterm, a common terminal
+entry that supports color is `xterm-color', so setting TERM's value to
+`xterm-color' might activate the color support.
+
+When Emacs runs on MS-DOS or MS-Windows systems, it always supports
+colors, so the above is only relevant for Unix and GNU/Linux systems.
+
+Some editing modes do not use colors unless you turn on the Font-lock
+mode.  One easy way of doing that is by typing "M-x
+global-font-lock-mode RET".
+
 * Problems in Emacs built with LessTif.
 
 The problems seem to depend on the version of LessTif and the Motif