Qt apps can't run under Mir [Gtk-WARNING **: cannot open display: ]

[Daniel van Vugt]

Qt apps can't run under Mir - fail with a Gtk error trying to open an X display (!?)

$ qterminal --desktop_file_hint=unity8
Loading module: 'libubuntu_application_api_desktop_mirclient.so.3.0.0'

(qterminal:9053): Gtk-WARNING **: cannot open display:

$ qtcreator --desktop_file_hint=unity8
Loading module: 'libubuntu_application_api_desktop_mirclient.so.3.0.0'

(qtcreator:9083): Gtk-WARNING **: cannot open display:

[Daniel van Vugt (vanvugt)]

Hmm, ubuntu-app-launch works for Unity8. But it would be nice if we could figure out how to make Qt apps generally just work in any Mir server without such workarounds.

[Alan Griffiths (alan-griffiths)]

Something like mirrun?

[Alan Griffiths (alan-griffiths)]

Really, I've been running qt apps under mir_demo_server, miral-shell and egmde for ages, there isn't a problem. You need:

sudo apt-get install qtubuntu-desktop mir-utils

And then:

mirrun qterminal

[Daniel van Vugt (vanvugt)]

Thanks. That led me to discover it was the presence of QT_QPA_PLATFORMTHEME that caused the failure.