I have a function bound to Ctrl-b, this runs a command immediately, however after some time running emacs, pressing this binding shows text C-b in the message bar, prompting for other keys to be pressed.

If I press Enter, it runs the command, otherwise it keeps accepting key and mouse input.

C-h k still shows up this key binding as being associated with the function I expect it to run.

How to troubleshoot emacs expecting further input for a key binding?

Edit: the command (which I wasn't sure if it was important) is to build.

(defun generic-build ()
    ((string= major-mode "c-mode")
      (call-interactively 'cmake-ide-compile))
    ((string= major-mode "c++-mode")
      (call-interactively 'cmake-ide-compile))

(global-set-key (kbd "C-b") 'generic-build)
(eval-after-load "evil-maps"
  (define-key evil-motion-state-map "\C-b" nil))

Update 1:

This happens if I try to exit too, Pressing Ctrk-b, Ctrl-h shows this message.

This would have to be related to my configuration, the issue just never came up until recently.

Type SPC or ‘y’ to save the current buffer;
DEL or ‘n’ to skip the current buffer;
RET or ‘q’ to give up on the save (skip all remaining buffers);
C-g to quit (cancel the whole command);
! to save all remaining buffers;
C-r to view this buffer;
d to view changes in this buffer;
or . (period) to save the current buffer and exit.

I'm using:

(setq use-dialog-box nil)

Which has been working up until now.

Using emacs -Q, then setting (setq use-dialog-box nil) still prompts for file save.

Update 2:

Found the root cause, posting in answer since its confusing to include here.

  • If it had been converted to a prefix binding then you could type C-b C-h to see which bindings were using that prefix; however that does not match your description. Please update the question with details of the specific function in question. My best guess is that this is actually expected behaviour.
    – phils
    Mar 13, 2018 at 11:18
  • It's a function I wrote, it simply triggers a build. It doesnt do anything interactive. The reason this is not expected behavior is it does not do this when I first open emacs. after 10min use+ ... it starts to do it (not scientific I know, I'm just not sure what triggers it).
    – ideasman42
    Mar 13, 2018 at 13:41
  • Do you see the same problem when you start Emacs with emacs -Q (no init file), and then define your command and bind it to the key? If not, bisect your init file to find the culprit.
    – Drew
    Mar 13, 2018 at 16:38
  • 1
    As phils wrote, either C-b C-h or C-b ? will tell you what bindings are available. Some of those bindings must have overwritten your original one.
    – wvxvw
    Mar 13, 2018 at 19:07
  • Show us the function.
    – phils
    Mar 13, 2018 at 19:49

2 Answers 2


Glad to know you resolved the problem. Since your question is about troubleshooting keybindings I'd like to chip in with my key troubleshooting process.

Try using C-h b when you can't properly query C-h k for the command bound to a key.
The C-h b (M-x describe-bindings) command describes all active key bindings for the buffer.

It's easy to scan this table for any clashes with an existing prefix command. A clash of this type could explain why your key was waiting for more key stroke input.

When a problem happens only after I've been interacting with Emacs for some time this is often because I indirectly loaded features when searching for their documentation with C-h f and C-h v.

In this case comparing the output of C-h m could help find problems introduced when a new mode is loaded, maybe unexpectedly or inadvertently.


This problem is messages are being suppressed by this advice-function.

somehow it's not limited to ispell-init-process:

(defun message-off-advice (oldfun &rest args)
  "Quiet down messages in adviced OLDFUN."
  (let ((message-off (make-symbol "message-off")))
      (advice-add #'message :around #'ignore (list 'name message-off))
      (apply oldfun args))
      (advice-remove #'message message-off))))

(advice-add #'ispell-init-process :around #'message-off-advice)

See answer: https://emacs.stackexchange.com/a/36626/2418

  • "somehow it's not limited to ispell-init-process" - yes, it completely disables message when ispell-init-process is called until that call ends. That includes asynchronous calls, since I see that ispell-init-process uses accept-process-output.
    – npostavs
    Apr 13, 2018 at 11:26

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