Question about the XDG_SESSION_TYPE environmental variable

Lennart Poettering mzkqt at
Fri Jul 20 08:48:04 UTC 2018

On Fr, 20.07.18 09:19, Michal Srb (msrb at wrote:

> GTK currently unconditionally prefer Wayland and I have hit a bug when GTK 
> applications started from X11 session start in unrelated Wayland session. So I 
> tried to advocate the use of this variable for backend selection in GTK: 
> However the authors are reluctant to use the XDG_SESSION_TYPE variable without 
> seeing further documentation or some discussion on where it came from. Does 
> anything like that exist? If not, is there chance the variable will be 
> "standardized"?

I have commented on the bug. TLDR: they have never been formalized as
fdo spec, but they are documented by systemd and are official API of
it. if you want to make them an fdo spec, by all means go ahead, you
have my support, but I am not going to do the work, for me personally
systemd docs are good enough ;-)


Lennart Poettering, Red Hat

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