@Stebalien Which approach do you use to handle Emacs nesting? This is not my common setup, but nevertheless I sometimes like to start a nested Emacs instance and then I need to detect the outer EXWM. This also applies to scripts which want to detect the window manager. Maybe we can use a (quasi-)standardized variable for the active window manager, e.g., set XDG_CURRENT_DESKTOP and XDG_SESSION_DESKTOP (DESKTOP, SESSION, DESKTOP_SESSION, ...) to exwm?

I don't use a nested setup but I do set an EXWM=1 environment variable (which is a bit of a hack, I admit). IMO, setting the XDG variables is likely better, but we should expect a bit of breakage from Gnome packages (IIRC).

I set x-no-window-manager as well.

IMO, setting the XDG variables is likely better, but we should expect a bit of breakage from Gnome packages (IIRC).

Which breakage do you expect? Do you have some references?

Hmm, I looked a bit around and found some discussions:

• xdg-desktop qtile/qtile#3896
• Set DesktopNames in sway.desktop to have XDG_CURRENT_DESKTOP swaywm/sway#4876
• XDG_CURRENT_DESKTOP no longer getting set i3/i3#3509

So it seems that most window managers don't set this and leave the responsibility to the login or session script. Unfortunately this won't work for the purpose of detecting EXWM and determining if EXWM should be started or not, since for this to work the variable must be set inside Emacs itself. I think this leaves us no other choice than going with a custom variable, even if a little bit hackish?

Which breakage do you expect? Do you have some references?

At this point, all I remember is a vague "it caused some problems". But that was a while ago and I didn't put any effort into resolving those issues (and I might just be misremembering the entire thing). So I'd just go for it.

So it seems that most window managers don't set this and leave the responsibility to the login or session script. Unfortunately this won't work for the purpose of detecting EXWM and determining if EXWM should be started or not, since then the variable must be set by EXWM itself. I think this leaves us no other choice than going with a custom variable, even if a little bit hackish?

Technically it should be set by the login manager, but, IMO, setting it if it's not already set is also reasonable.

Technically it should be set by the login manager, but, IMO, setting it if it's not already set is also reasonable.

Agree. However it won't work for the nested Emacs purpose then if it could also have been set already from outside.

Agree. However it won't work for the nested Emacs purpose then if it could also have been set already from outside.

How so? If we change it from within Emacs, all Emacs sub-processes will inherit the new value.

How so? If we change it from within Emacs, all Emacs sub-processes will inherit the new value.

It is a hypothetical case, since the login manager doesn't set the variable yet to EXWM. But assume it would set XDG_CURRENT_DESKTOP=EXWM, then the following check wouldn't work in the init.el:

(unless (equal "XDG_CURRENT_DESKTOP" "EXWM")
   (exwm-enable))

The check is needed for the aformentioned nesting of Emacs instances.

(I've added a commit to the master branch for now which only sets the x-no-window-manager variable.)

Oh, I see. Yeah, that wouldn't work. Honestly, for that I'd just check the INSIDE_EMACS variable.

Ah... and that's set regardless, I thought that was only set in sub-shells.

Ah... and that's set regardless, I thought that was only set in sub-shells.

(getenv "INSIDE_EMACS") evaluates to nil. Nevertheless I originally had planned to set the INSIDE_EXWM environment variable in exwm-enable which mirrors INSIDE_EMACS.

(getenv "INSIDE_EMACS") evaluates to nil. Nevertheless I originally had planned to set the INSIDE_EXWM environment variable which mirrors INSIDE_EMACS.

It evaluates to 31.0.50,emacs on my system but... that may be just my config.

But INSIDE_EXWM sounds reasonable.

It evaluates to 31.0.50,emacs on my system but... that may be just my config.

I am still on 30, but there INSIDE_EMACS is only non-nil inside Eshell. In the scratch buffer it evaluates to nil. But anyway, I think this is not reliable enough. So let's just go with INSIDE_EXWM.

I am still on 30, but there INSIDE_EMACS is only non-nil inside Eshell. In the scratch buffer it evaluates to nil. But anyway, I think this is not reliable enough. So let's just go with INSIDE_EXWM.

Oh, lol. That's my fault. I got annoyed at it only showing up in shells so I set it globally so I can detect emacs from all sub-processes. (my config is way too big at this point)

Oh, lol. That's my fault. I got annoyed at it only showing up in shells so I set it globally so I can detect emacs from all sub-processes. (my config is way too big at this point)

Okay, I see. I still think INSIDE_EXWM is a good variable to have :)

I use lxqt-session to start the window manager, and XDG_SESSION_DESKTOP is lxqt.
What is better if I have two window managers (exwm and herbstluftwm) for two people?
Should I set XDG_CURRENT_DESKTOP in the session manager and check both (XDG_CURRENT_DESKTOP=exwm and INSIDE_EXWM=false) to load the exwm specific configs?
@minad Can you share your configuration?
Thank you very much!