qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.: "export QT_PLUGIN_PATH=/usr/lib/qt/plugins" doesn't work for me

[luca29q]

Re: [SOLVED] qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""

I have met the same error with @PieBru when excuting a Geant4 program with Qt5, and the solution provided by @hskoglund doesn't work for me.

I have added export QT_DEBUG_PLUGINS=1 to the ~/.bashrc file and the output when I excute my program is as follows:

Available UI session types: [ Qt, tcsh, csh ]
QFactoryLoader::QFactoryLoader() checking directory path "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libdxcb.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libdxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "dxcb"
        ]
    },
    "archreq": 0,
    "className": "DPlatformIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("dxcb")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqeglfs.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqeglfs.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "eglfs"
        ]
    },
    "archreq": 0,
    "className": "QEglFSIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("eglfs")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqlinuxfb.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqlinuxfb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "linuxfb"
        ]
    },
    "archreq": 0,
    "className": "QLinuxFbIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("linuxfb")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimal.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimal.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "archreq": 0,
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimalegl.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqminimalegl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimalegl"
        ]
    },
    "archreq": 0,
    "className": "QMinimalEglIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("minimalegl")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqoffscreen.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqoffscreen.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "archreq": 0,
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqvnc.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqvnc.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "vnc"
        ]
    },
    "archreq": 0,
    "className": "QVncIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("vnc")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-egl.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-egl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-egl"
        ]
    },
    "archreq": 0,
    "className": "QWaylandEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("wayland-egl")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-generic.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-generic.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland"
        ]
    },
    "archreq": 0,
    "className": "QWaylandIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("wayland")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-egl.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-egl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-egl"
        ]
    },
    "archreq": 0,
    "className": "QWaylandXCompositeEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("wayland-xcomposite-egl")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-glx.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqwayland-xcomposite-glx.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-glx"
        ]
    },
    "archreq": 0,
    "className": "QWaylandXCompositeGlxPlatformIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("wayland-xcomposite-glx")
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so"
Found metadata in lib /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "archreq": 0,
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 330752
}


Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/home/heartfield/geant4/geant4-v11.2.1/examples/basic/B1/test/platforms" ...
loaded library "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so"
qt.qpa.xcb: could not connect to display :0
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: dxcb, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Aborted

The output after excuting ldd /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so is as follows:

        linux-vdso.so.1 (0x00007ffcf65f9000)
        libQt5XcbQpa.so.5 => /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 (0x00007f9434cfa000)
        libQt5Gui.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 (0x00007f943470f000)
        libQt5Core.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 (0x00007f94341c6000)
        libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f9433fe4000)
        libc.so.6 => /usr/lib/x86_64-linux-gnu/libc.so.6 (0x00007f9433df2000)
        libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007f9433dab000)
        libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f9433cea000)
        libQt5DBus.so.5 => /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5 (0x00007f9433c4e000)
        libpthread.so.0 => /usr/lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9433c2b000)
        libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f9433c26000)
        libxcb-xinput.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-xinput.so.0 (0x00007f9433c02000)
        libxcb-icccm.so.4 => /usr/lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007f9433bfb000)
        libxcb-image.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007f94339f4000)
        libxcb-shm.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007f94339ef000)
        libxcb-keysyms.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007f94339ea000)
        libxcb-randr.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007f94339d7000)
        libxcb-render-util.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007f94339d0000)
        libxcb-render.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007f94339c1000)
        libxcb-shape.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007f94339ba000)
        libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007f94339b0000)
        libxcb-xfixes.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007f94339a6000)
        libxcb-xinerama.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-xinerama.so.0 (0x00007f94339a1000)
        libxcb-xkb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007f9433983000)
        libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f9433959000)
        libXrender.so.1 => /usr/lib/x86_64-linux-gnu/libXrender.so.1 (0x00007f943374d000)
        libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f9433610000)
        libm.so.6 => /usr/lib/x86_64-linux-gnu/libm.so.6 (0x00007f94334c1000)
        libSM.so.6 => /usr/lib/x86_64-linux-gnu/libSM.so.6 (0x00007f94334b6000)
        libICE.so.6 => /usr/lib/x86_64-linux-gnu/libICE.so.6 (0x00007f9433498000)
        libxkbcommon-x11.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007f943348d000)
        libxkbcommon.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007f9433449000)
        libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f943331f000)
        libgcc_s.so.1 => /usr/lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f9433304000)
        libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f943327c000)
        libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f9433244000)
        libz.so.1 => /usr/lib/x86_64-linux-gnu/libz.so.1 (0x00007f9433226000)
        libharfbuzz.so.0 => /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007f9433122000)
        libicui18n.so.66 => /usr/lib/x86_64-linux-gnu/libicui18n.so.66 (0x00007f9432e23000)
        libicuuc.so.66 => /usr/lib/x86_64-linux-gnu/libicuuc.so.66 (0x00007f9432c3d000)
        libdl.so.2 => /usr/lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9432c37000)
        libpcre2-16.so.0 => /usr/lib/x86_64-linux-gnu/libpcre2-16.so.0 (0x00007f9432bb3000)
        libdouble-conversion.so.3 => /usr/lib/x86_64-linux-gnu/libdouble-conversion.so.3 (0x00007f9432b9b000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f9434e97000)
        libexpat.so.1 => /usr/lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f9432b6d000)
        libuuid.so.1 => /usr/lib/x86_64-linux-gnu/libuuid.so.1 (0x00007f9432b64000)
        libdbus-1.so.3 => /usr/lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f9432b13000)
        libxcb-util.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-util.so.1 (0x00007f943290d000)
        libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f9432905000)
        libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f94328fd000)
        libbsd.so.0 => /usr/lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f94328e3000)
        libpcre.so.3 => /usr/lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f9432870000)
        libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f94327b8000)
        libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f9432782000)
        libgraphite2.so.3 => /usr/lib/x86_64-linux-gnu/libgraphite2.so.3 (0x00007f9432755000)
        libicudata.so.66 => /usr/lib/x86_64-linux-gnu/libicudata.so.66 (0x00007f9430c94000)
        libsystemd.so.0 => /usr/lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f9430be5000)
        librt.so.1 => /usr/lib/x86_64-linux-gnu/librt.so.1 (0x00007f9430bdb000)
        liblzma.so.5 => /usr/lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f9430bb0000)
        liblz4.so.1 => /usr/lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f9430b8f000)
        libgcrypt.so.20 => /usr/lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f9430a71000)
        libgpg-error.so.0 => /usr/lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f9430a4e000)

I've tried as you suggested @hskoglund , adding export QT_PLUGIN_PATH=/usr/lib/x86_64-linux-gnu/qt5/plugins to the ~/.bashrc file, but it doesn't work.

What should I do? Really Thanks!

My system information:
WSL1 on Ubuntu 20.02 LTS

[luca29q]

Thank you @JonB , I can run my Geant4 program now using VcXsvr instead of Xming.

I first ran Xlaunch under the VcXsvr folder, with interface set as follows:

and then select Disable access control on the last page.

Then I added the following statements to the file ~/.bashrc:

export DISPLAY=`cat /etc/resolv.conf | grep nameserver | awk '{print $2}'`:0.0
export DISPLAY=192.168.144.1:0.0  //[WSL IPv4 Address]:[DISPLAY NUMBER]
export WAYLAND_DISPLAY=$DISPLAY
export XDG_SESSION_TYPE=x11

Then I can successfully run command startxfce4 to open the Ubuntu virtual desktop, and my Geant4 program can run normally.

I'm still not sure exactly what my problem was, but I'm guessing it's probably because my system is WSL2 (I just found that today and I thought it's WSL1...), and my problem seems to be fixed for now.

Really thank you guys for your help and guidance! Hope everything goes well with you @jsulm @JonB

[jsulm]

@luca29q said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.: "export QT_PLUGIN_PATH=/usr/lib/qt/plugins" doesn't work for me:

file and the output when I excute my program is as follows

Please post more, what you show does not contain any information about the issue.
And please keep titles of your threads shorter.

[luca29q]

Really thank you for your reply @jsulm , I have posted all the output before and I guess the information related to the issue is at the bottom of the output:

@luca29q said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.: "export QT_PLUGIN_PATH=/usr/lib/qt/plugins" doesn't work for me:

qt.qpa.xcb: could not connect to display :0
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

According to solutions posted in [SOLVED] qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "", I have added export QT_PLUGIN_PATH=/usr/lib/x86_64-linux-gnu/qt5/plugins to the ~/.bashrc file but it doesn't work.

I'm sorry I made the headline too long, but I haven't found a way to change the title so far. If there is a remedy, please let me know.

Please tell me what I can do. Thank you for your time again.

[jsulm]

@luca29q said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.: "export QT_PLUGIN_PATH=/usr/lib/qt/plugins" doesn't work for me:

I have posted all the output before

Yes, you did, I was blind.

This is the important error: "qt.qpa.xcb: could not connect to display :0"
Is X11 running on that machine?

[luca29q]

Thank you for your reply @jsulm , I think X11 is running well on my machine. I have installed Xming on Windows 10 and Xfce4 on WSL1. Do I need another package?

[jsulm]

@luca29q said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.: "export QT_PLUGIN_PATH=/usr/lib/qt/plugins" doesn't work for me:

I have installed Xming on Windows 10 and Xfce4 on WSL1

But is X11 running or not? I mean not just installed but also running at the time you're trying to start your app.

[JonB]

@luca29q

qt.qpa.xcb: could not connect to display :0

This is the only line which matters. Your plugin is loading fine. Your problem is connecting to the X server. Try something like xterm and see if that does produce the same error.

[luca29q]

Sorry for my late reply and thank you for reminding me to check whether X11 can run or not @jsulm . I found that I couldn't start Ubuntu's virtual desktop properly. I first ran Xlaunch under Windows and then executed sudo startxfce4 in WSL with the following output:

/usr/bin/startxfce4: X server already running on display localhost:0
xrdb: Connection refused
xrdb: Can't open display ':0'
Unable to init server: Could not connect: Connection refused
xfce4-session: Cannot open display: .
Type 'xfce4-session --help' for usage.

I execute the xclock command and the output is as follows:
Error: Can't open display: :0

I wonder if there is a problem with my Ubuntu installation, how can I fix it?

[luca29q]

Thank you for your suggestion @JonB , I'm about to try Xterm, but I tried VcXsrv and got some different errors.

After installing VcXsrv, I add

export DISPLAY=`cat /etc/resolv.conf | grep nameserver | awk '{print $2}'`:0.0
export DISPLAY=192.168.144.1:0.0 //[WSL IPv4 Address]:[DISPLAY NUMBER]
export WAYLAND_DISPLAY=$DISPLAY

to ~/.bashrc, then the output when excuting startxfce4 is as follows:

/usr/bin/startxfce4: X server already running on display 192.168.144.1:0.0
_IceTransmkdir: Owner of /tmp/.ICE-unix should be set to root
gpg-agent[1411]: WARNING: "--write-env-file" is an obsolete option - it has no effect
gpg-agent: a gpg-agent is already running - not starting a new one

(xfce4-session:1374): xfce4-session-WARNING **: 13:54:50.554: gpg-agent returned no PID in the variables

(xfce4-session:1374): xfce4-session-WARNING **: 13:54:50.558: xfsm_manager_load_session: Something wrong with /home/heartfield/.cache/sessions/xfce4-session-192.168.144.1:0, Does it exist? Permissions issue?

(xfsettingsd:1431): libupower-glib-WARNING **: 13:54:55.113: Couldn't connect to proxy: Could not connect: No such file or directory

(xfsettingsd:1431): libupower-glib-CRITICAL **: 13:54:55.113: up_client_get_lid_is_closed: assertion 'UP_IS_CLIENT (client)' failed

(xfsettingsd:1431): GLib-GObject-WARNING **: 13:54:55.113: invalid (NULL) pointer instance

(xfsettingsd:1431): GLib-GObject-CRITICAL **: 13:54:55.113: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(wrapper-2.0:1445): GLib-GIO-CRITICAL **: 13:54:55.420: g_file_new_for_path: assertion 'path != NULL' failed

(wrapper-2.0:1445): GLib-GIO-CRITICAL **: 13:54:55.421: g_file_monitor_file: assertion 'G_IS_FILE (file)' failed

(wrapper-2.0:1445): GLib-GObject-WARNING **: 13:54:55.421: invalid (NULL) pointer instance

(wrapper-2.0:1445): GLib-GObject-CRITICAL **: 13:54:55.421: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(wrapper-2.0:1445): Gtk-WARNING **: 13:54:55.421: Attempting to add a widget with type GtkToggleButton to a container of type XfcePanelPlugin, but the widget is already inside a container of type XfcePanelPlugin, please remove the widget from its existing container first.

(xfce4-session:1374): xfce4-session-WARNING **: 13:54:55.438: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

(xfce4-session:1374): xfce4-session-WARNING **: 13:54:55.440: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

(xfce4-session:1374): xfce4-session-WARNING **: 13:54:55.441: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

** (wrapper-2.0:1444): WARNING **: 13:54:55.442: Binding 'XF86AudioMicMute' failed!

(wrapper-2.0:1444): pulseaudio-plugin-WARNING **: 13:54:55.442: Could not have grabbed volume control keys. Is another volume control application (xfce4-volumed) running?

(wrapper-2.0:1444): Gtk-WARNING **: 13:54:55.686: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner PulseaudioButton)

(wrapper-2.0:1445): Gtk-WARNING **: 13:54:55.686: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner GtkToggleButton)

** (xiccd:1466): CRITICAL **: 13:54:55.704: Failed to connect to colord: Could not connect: No such file or directory

** (agent:1472): CRITICAL **: 13:54:55.725: Failed to get connection to system bus: Could not connect: No such file or directory
Connection failure: Connection refused
pa_context_connect() failed: Connection refused

(nm-applet:1477): nm-applet-WARNING **: 13:54:55.907: Error connecting to system D-Bus: Could not connect: No such file or directory

(nm-applet:1477): nm-applet-WARNING **: 13:54:55.908: Could not connect: No such file or directory

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.912: ((libnm/nm-client.c:3905)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.913: ((libnm/nm-client.c:3859)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.913: ((libnm/nm-client.c:3937)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.913: ((libnm/nm-client.c:3986)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.913: ((libnm/nm-client.c:4026)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.914: ((libnm/nm-client.c:4042)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.914: ((libnm/nm-client.c:4080)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.914: ((libnm/nm-client.c:4598)): assertion '<dropped>' failed

(nm-applet:1477): libnm-CRITICAL **: 13:54:55.914: ((libnm/nm-client.c:4598)): assertion '<dropped>' failed

(xfdesktop:1447): GVFS-RemoteVolumeMonitor-WARNING **: 13:54:55.954: remote volume monitor with dbus name org.gtk.vfs.UDisks2VolumeMonitor is not supported
system-config-printer-applet: failed to connect to system D-Bus

** (xfdesktop:1447): WARNING **: 13:54:56.179: Failed to get system bus: Could not connect: No such file or directory

[JonB]

@luca29q
I'm afraid I don't understand whether this means you still have a problem or what to do about it if you do. I only know that the issue is connecting to your display not the xcb plugin itself, and you can see similar problems outside of your Qt application.

[luca29q]

Thank you @JonB , I can run my Geant4 program now using VcXsvr instead of Xming.

I first ran Xlaunch under the VcXsvr folder, with interface set as follows:

and then select Disable access control on the last page.

Then I added the following statements to the file ~/.bashrc:

export DISPLAY=`cat /etc/resolv.conf | grep nameserver | awk '{print $2}'`:0.0
export DISPLAY=192.168.144.1:0.0  //[WSL IPv4 Address]:[DISPLAY NUMBER]
export WAYLAND_DISPLAY=$DISPLAY
export XDG_SESSION_TYPE=x11

Then I can successfully run command startxfce4 to open the Ubuntu virtual desktop, and my Geant4 program can run normally.

I'm still not sure exactly what my problem was, but I'm guessing it's probably because my system is WSL2 (I just found that today and I thought it's WSL1...), and my problem seems to be fixed for now.

Really thank you guys for your help and guidance! Hope everything goes well with you @jsulm @JonB