Cannot load Xcb.

Urmom

Does anybody know why qt cannot load Xcb

This exact error message:

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: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

Aborted

Christian Ehrlicher

What's your OS? How did you install QtCreator?

Urmom

@Christian-Ehrlicher I am using Debian 10 and I used Pip.

SGaist

Hi and welcome to devnet,

Please start your script with the QT_DEBUG_PLUGINS environment variable set to 1 to see why the plugin cannot be loaded.

You are likely missing one or more dependencies on your machine.

Christian Ehrlicher

So searching in the forum for "xcb qtcreator" you can find e.g. https://forum.qt.io/topic/121806/qtcreator-could-not-load-platform-plugin-xcb

Urmom

@Christian-Ehrlicher That did not really help

Christian Ehrlicher

@Urmom said in Cannot load Xcb.:

That did not really help

What did you try? Where is your output after you set QT_DEBUG_PLUGINS as @SGaist and the other post suggested?

Urmom

@Christian-Ehrlicher said in Cannot load Xcb.:

QT_DEBUG_PLUGINS

The output is:

QFactoryLoader::QFactoryLoader() checking directory path "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqeglfs.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("eglfs")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqlinuxfb.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("linuxfb")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqminimal.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqminimalegl.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("minimalegl")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqoffscreen.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqvnc.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("vnc")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwayland-egl.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("wayland-egl")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwayland-generic.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("wayland")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwayland-xcomposite-egl.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("wayland-xcomposite-egl")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwayland-xcomposite-glx.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("wayland-xcomposite-glx")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwebgl.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqwebgl.so, metadata=
{
"IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
"MetaData": {
"Keys": [
"webgl"
]
},
"archreq": 0,
"className": "QWebGLIntegrationPlugin",
"debug": false,
"version": 331520
}

Got keys from plugin meta data ("webgl")
QFactoryLoader::QFactoryLoader() looking at "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so"
Found metadata in lib /usr/local/lib/python3.7/dist-packages/PyQt5/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": 331520
}

Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
Cannot load library /usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)
QLibraryPrivate::loadPlugin failed on "/usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so" : "Cannot load library /usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)"
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: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

Aborted

JonB

@Urmom said in Cannot load Xcb.:

Cannot load library /usr/local/lib/python3.7/dist-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)

In the thread @Christian-Ehrlicher referred you to, https://forum.qt.io/topic/121806/qtcreator-could-not-load-platform-plugin-xcb, there is useful stuff about this. There are various things to look for. There are suggestions including

You can create a symbolic link libcxb-util.so.1 --> libcxb-util.so.0 to fix the issue

and https://bugreports.qt.io/browse/QTBUG-88688. Are these your situation? I think you'll find they are....

eyllanesc

@Urmom execute sudo apt-get install '^libxcb.*-dev' libx11-xcb-dev libglu1-mesa-dev libxrender-dev libxi-dev libxkbcommon-dev libxkbcommon-x11-dev from https://wiki.qt.io/Building_Qt_5_from_Git

Urmom

@eyllanesc Thank you that worked