Re: Emacs's set-frame-size can not work well with gnome-shell?

[Dmitry Gutov]

On 07.04.2020 11:33, martin rudalics wrote:
>  > By the way, any chance we can have a variable or an accessor function
>  > that would return what the current WM identifies as?
>
> I started to look into this but with meager results so far.  From what I
> read on the Web there's no standardized approach to find that out.

So far the best option I've found is the XDG_CURRENT_DESKTOP env var. 
But indeed it only says "GNOME" (or "ubuntu:GNOME" on my machine), never 
mentioning Mutter.

But if Mate sets it to something different, at least, that could work 
well enough for the purposes of posframe.

The other, more nuanced option, is:

  grep -sl mutter /proc/*/maps

https://unix.stackexchange.com/a/512207/166215

>  > And also, what's the best way to detect which toolkit was Emacs
>  > compiled with? Only look for 'gtk3' substring in
>  > system-configuration-options?
>
> It might not be there when the default is used.  It's hidden somewhere
> behind C-h C-a.

(string-match-p "GTK3" system-configuration-features) seems to do the trick.