Fix bug #7667: mention debug-on-quit in the manual.

 trouble.texi (Checklist): Mention debug-on-quit.

2 files changed, 11 insertions, 0 deletions

diff --git a/doc/emacs/ChangeLog b/doc/emacs/ChangeLog
index 7fa2c1aaf76..d0ad25bb1af 100644
--- a/doc/emacs/ChangeLog
+++ b/doc/emacs/ChangeLog
@@ -1,3 +1,7 @@
+2010-12-25  Eli Zaretskii  <eliz@gnu.org>
+
+        * trouble.texi (Checklist): Mention debug-on-quit.  (Bug#7667)
+
 2010-12-18  Glenn Morris  <rgm@gnu.org>
 
         * maintaining.texi: Move inclusion of emerge after EDE, so that it
diff --git a/doc/emacs/trouble.texi b/doc/emacs/trouble.texi
index ef8b5ab6772..b8cfd322bd4 100644
--- a/doc/emacs/trouble.texi
+++ b/doc/emacs/trouble.texi
@@ -806,6 +806,13 @@ This use of the debugger is possible only if you know how to make the
 bug happen again.  If you can't make it happen again, at least copy
 the whole error message.
 
+@vindex debug-on-quit
+If Emacs appears to be stuck in an infinite loop or in a very long
+operation, typing @kbd{C-g} with the variable @code{debug-on-quit}
+non-@code{nil} will start the Lisp debugger and show a backtrace.
+This backtrace is useful for debugging such long loops, so if you can
+produce it, copy it into the bug report.
+
 @item
 Check whether any programs you have loaded into the Lisp world,
 including your @file{.emacs} file, set any variables that may affect the