Debian – emacs can’t open display

debianemacslinuxx11xorg

Just recently this has started happening; I run: /usr/bin/emacsclient --alternate-editor="" --no-wait -c and get:

ERROR: Display :0.0 can't be opened

No other applications do this.

The output from xdpyinfo:

name of display:    :0.0
version number:    11.0
vendor string:    The X.Org Foundation
vendor release number:    10707000
X.Org version: 1.7.7
.....

Edit:

I discovered that old emacs servers/daemons are still running.

$ps ux | grep [e]macs
richard   2642  0.0  0.8  38788 24984 ?        Ss   Jun22   0:25 emacs --daemon
richard   7512  0.0  0.6  33896 19720 ?        Ss   Jun23   0:05 emacs --daemon
richard  15458  0.0  0.6  32836 19076 ?        Ss   09:40   0:01 emacs --daemon

Does anyone have any ideas how these can be shut-down when I log-off?

Best Answer

Given the additional info, I guess that your emacsclient is connecting to the "wrong" emacs server. (Or better, the first one that was started: subsequent invocations of emacs --daemon will fail to start the server since the communication socket is already in use.) If the emacs daemon was started in a previous X session, then it's using the wrong credentials for connecting to the X display and thus fails.

You can find out which emacs process is running the server by connecting to it in non-graphics/tty mode; run emacsclient in a terminal with the -nw option:

emacsclient -nw

You can kill a running emacs by having it run LISP code through emacsclient:

emacsclient -t --eval '(progn (server-save-buffers-kill-terminal 1) (save-buffers-kill-emacs 1))'

where:

  • the -t option (alias for -nw or --tty) is to avoid Emacs connecting to the X display;
  • the server-save-buffers-kill-terminal detaches the emacsclient before you tell Emacs to stop (otherwise it will issue a confirmation prompt);
  • the save-buffers-kill-emacs function is what is normally invoked by C-x C-c, argument 1 tells Emacs not to ask for confirmation.

In addition, I guess the reason you are having so many emacs --daemon running is that you invoke emacsclient with the --alternate-editor="" option: the man page emacsclient(1) states that:

If the value of (the alternate) EDITOR is the empty string, then Emacs is started in daemon mode and emacsclient will try to connect to it.

It could be a better option to start emacs --daemon from your X session startup script (e.g., .gnomerc or the GNOME session configutation) so that the session manager will take care of killing the emacs daemon when the session terminates.

Related Question