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qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

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  • T trimixotun

    It's looks slightly outdated, but maybe it someone helps:

    1. Debian 10 x86-64.
    2. LXDE
    3. Fresh net install Qt 5.12.10

    Qtcreator first launch problem: "qt.qpa.plugin: Could not load the Qt platform plugin "xcb"".

    Nothing from above helps at all. Qtcreator needs libxcb-util.so.1, but system has only libxcb-util.so.

    Simple solution:

    sudo ln -s /usr/lib/x86_64-linux-gnu/libxcb-util.so /usr/lib/x86_64-linux-gnu/libxcb-util.so.1

    All work, folks.

    W Offline
    W Offline
    wobl
    wrote on last edited by wobl
    #81

    @trimixotun said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

    sudo ln -s /usr/lib/x86_64-linux-gnu/libxcb-util.so /usr/lib/x86_64-linux-gnu/libxcb-util.so.1

    Thanks a lot ... this is working for MX Linux too - but with a little correction:

    sudo ln -s /usr/lib/x86_64-linux-gnu/libxcb-util.so.0.0.0 /usr/lib/x86_64-linux-gnu/libxcb-util.so.1
    
    1 Reply Last reply
    1
    • S Srinivas Reddy

      I am using Qt-5.15.0, got the same problem.
      More details are:
      QLibraryPrivate::loadPlugin failed on "/opt/Qt/5.15.0/gcc_64/plugins/platforms/libqxcb.so" : "Cannot load library /opt/Qt/5.15.0/gcc_64/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: cannot open shared object file: No such file or directory)"

      Solved by installing the dependent package.
      Command to install: sudo apt-get install libxcb-xinerama0

      N Offline
      N Offline
      nileshmoodley
      wrote on last edited by
      #82

      @Srinivas-Reddy Thank you very much - this solved it for me!

      1 Reply Last reply
      0
      • J Offline
        J Offline
        Jean-Noel
        wrote on last edited by Jean-Noel
        #83

        For me (on Debian), the only thing that worked was to completely uninstall Qt with Maintenance Tool, and install with "default" configuration.

        1 Reply Last reply
        0
        • A Offline
          A Offline
          ajlogo
          wrote on last edited by
          #84

          The plugin problem started when I re-created an Anaconda env (PyQt5 and ubuntu) from a .yml file.
          https://newini.wordpress.com/2020/08/13/how-to-solve-xcb-plugin-error-in-pyqt5/
          Had the working answer for me:
          sudo apt-get install qt5-default # For Ubuntu system

          1 Reply Last reply
          0
          • SGaistS SGaist

            HI,

            Did you run ldd on your libraries and libxcb-xinerama versions ?

            P Offline
            P Offline
            pixel_08
            wrote on last edited by
            #85

            @SGaist hi,
            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.
            /bin/bash: line 133: 1745 Aborted (core dumped) python csv2txt.py

            Then I added, export QT_DEBUG_PLUGINS=1
            got error as,
            QFactoryLoader::QFactoryLoader() checking directory path "/usr/local/bin/platforms" ...
            Cannot load library /builds/sravani_detect/video_frames/venv/lib/python3.9/site-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 "/builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so" : "Cannot load library /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)"

            and ran ldd /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so

            linux-vdso.so.1 (0x00007ffc728e9000)
            libQt5XcbQpa.so.5 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libQt5XcbQpa.so.5 (0x00007fda88aa2000)
            libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007fda88a50000)
            libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007fda88994000)
            libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fda88776000)
            libQt5Gui.so.5 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libQt5Gui.so.5 (0x00007fda87e45000)
            libQt5DBus.so.5 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libQt5DBus.so.5 (0x00007fda87bb7000)
            libQt5Core.so.5 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libQt5Core.so.5 (0x00007fda873c1000)
            libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007fda8732d000)
            libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fda8730c000)
            libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007fda87307000)
            libxcb-icccm.so.4 => /usr/lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007fda87300000)
            libxcb-image.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007fda870f9000)
            libxcb-shm.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007fda870f4000)
            libxcb-util.so.1 => not found
            libxcb-keysyms.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007fda86ef1000)
            libxcb-randr.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007fda86edf000)
            libxcb-render-util.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007fda86cdb000)
            libxcb-render.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007fda86cca000)
            libxcb-shape.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007fda86cc5000)
            libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007fda86cbb000)
            libxcb-xfixes.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007fda86cb1000)
            libxcb-xinerama.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-xinerama.so.0 (0x00007fda86cac000)
            libxcb-xkb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007fda86c8e000)
            libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007fda86c62000)
            libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007fda86a50000)
            libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007fda8690f000)
            libxkbcommon-x11.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007fda86904000)
            libxkbcommon.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007fda868c2000)
            libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fda868bd000)
            libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fda86737000)
            libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fda865b4000)
            libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fda8659a000)
            libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fda863d9000)
            libxcb-util.so.1 => not found
            libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007fda863d4000)
            libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007fda862b3000)
            libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007fda86276000)
            libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007fda8626d000)
            libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007fda86234000)
            libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007fda861e1000)
            libicui18n.so.56 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libicui18n.so.56 (0x00007fda85d46000)
            libicuuc.so.56 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libicuuc.so.56 (0x00007fda8598e000)
            libicudata.so.56 => /builds/sravani_detect/video_frames/venv/lib/python3.9/site-packages/PyQt5/Qt5/plugins/platforms/../../lib/libicudata.so.56 (0x00007fda83fab000)
            /lib64/ld-linux-x86-64.so.2 (0x00007fda89001000)
            libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007fda83f77000)
            libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007fda83eba000)
            libxcb-util.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-util.so.0 (0x00007fda83cb1000)
            libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007fda83aad000)
            libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007fda838a7000)
            libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fda83833000)
            libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007fda83790000)
            libbsd.so.0 => /usr/lib/x86_64-linux-gnu/libbsd.so.0 (0x00007fda83776000)
            librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fda8376c000)
            liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007fda83744000)
            liblz4.so.1 => /usr/lib/x86_64-linux-gnu/liblz4.so.1 (0x00007fda83725000)
            libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007fda83607000)
            libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007fda835e2000)

            what to do next?
            Thank you!

            1 Reply Last reply
            0
            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #86

              Install the package that provides "libxcb-util.so.1" on your system.

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

              P S 2 Replies Last reply
              1
              • SGaistS SGaist

                Install the package that provides "libxcb-util.so.1" on your system.

                P Offline
                P Offline
                pixel_08
                wrote on last edited by
                #87

                @SGaist
                Thank you, Can we run PyQt5 applications in gitlab by setting up a pipeline?
                Please clarify this.

                1 Reply Last reply
                0
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #88

                  Do you mean run tests on your GUI in GitLab ?

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  P 1 Reply Last reply
                  0
                  • SGaistS SGaist

                    Do you mean run tests on your GUI in GitLab ?

                    P Offline
                    P Offline
                    pixel_08
                    wrote on last edited by
                    #89

                    @SGaist yes

                    1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #90

                      Yes you can, you have to use the offscreen backend though unless your runner provides adequate connection to an X server.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply
                      0
                      • S Srinivas Reddy

                        I am using Qt-5.15.0, got the same problem.
                        More details are:
                        QLibraryPrivate::loadPlugin failed on "/opt/Qt/5.15.0/gcc_64/plugins/platforms/libqxcb.so" : "Cannot load library /opt/Qt/5.15.0/gcc_64/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: cannot open shared object file: No such file or directory)"

                        Solved by installing the dependent package.
                        Command to install: sudo apt-get install libxcb-xinerama0

                        S Offline
                        S Offline
                        Srinivas Reddy
                        wrote on last edited by
                        #91

                        @Srinivas-Reddy This worked for me. Thank you.

                        1 Reply Last reply
                        0
                        • J jarvis

                          Hi ,
                          I am facing a similar issue could you please help.

                          Got keys from plugin meta data ("xcb")
                          QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqeglfs.so"
                          Got keys from plugin meta data ("eglfs")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqlinuxfb.so"
                          Got keys from plugin meta data ("linuxfb")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqminimal.so"
                          Got keys from plugin meta data ("minimal")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqminimalegl.so"
                          Got keys from plugin meta data ("minimalegl")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqoffscreen.so"
                          Got keys from plugin meta data ("offscreen")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqvnc.so"
                          Got keys from plugin meta data ("vnc")
                          QFactoryLoader::QFactoryLoader() looking at "/usr/bin/platforms/libqxcb.so"
                          Got keys from plugin meta data ("xcb")
                          loaded library "/usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so"
                          qt.qpa.xcb: could not connect to display
                          qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/opt/appname/libs/Qt/plugins/platforms" 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, xcb.

                          S Offline
                          S Offline
                          steel357
                          wrote on last edited by
                          #92

                          @jarvis Hi jarvis,
                          I am also getting same problem
                          Got keys from plugin meta data ("webgl")
                          QFactoryLoader::QFactoryLoader() looking at "/home/vineeth/.local/lib/python3.8/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so"
                          Found metadata in lib /home/vineeth/.local/lib/python3.8/site-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" ...
                          loaded library "/home/vineeth/.local/lib/python3.8/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so"
                          qt.qpa.xcb: could not connect to display
                          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 (core dumped)

                          did u found the solution??

                          I am using Linux in windows(WSL)

                          1 Reply Last reply
                          0
                          • SGaistS SGaist

                            Install the package that provides "libxcb-util.so.1" on your system.

                            S Offline
                            S Offline
                            steel357
                            wrote on last edited by steel357
                            #93

                            @SGaist
                            @jarvis Hi guys,
                            I am also getting the same problem

                            Got keys from plugin meta data ("webgl")
                            QFactoryLoader::QFactoryLoader() looking at "/home/vineeth/.local/lib/python3.8/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so"
                            Found metadata in lib /home/vineeth/.local/lib/python3.8/site-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" ...
                            loaded library "/home/vineeth/.local/lib/python3.8/site-packages/PyQt5/Qt5/plugins/platforms/libqxcb.so"
                            qt.qpa.xcb: could not connect to display
                            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 (core dumped)

                            **did u found the solution??

                            I am using Linux in windows(WSL) and tried it normal ubuntu also getting same error**

                            1 Reply Last reply
                            0
                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #94

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

                              You should check the Windows documentation.

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                              1 Reply Last reply
                              0
                              • M Offline
                                M Offline
                                MBat
                                wrote on last edited by
                                #95

                                Good morning,

                                I am having trouble running a python code (not written by me) that uses pyroot.
                                My working system is Ubuntu 18.

                                At the start of the script I get the following message

                                cling::DynamicLibraryManager::loadLibrary(): /home/matteo/anaconda3/bin/../lib/libfontconfig.so.1: undefined symbol: FT_Done_MM_Var
                                Error in TInterpreter::TCling::AutoLoad: failure loading library libGX11TTF.so for TGX11TTF
                                cling::DynamicLibraryManager::loadLibrary(): /home/matteo/anaconda3/bin/../lib/libfontconfig.so.1: undefined symbol: FT_Done_MM_Var
                                Info in TApplication::InitializeGraphics: no TTF support

                                While, at the end, just before it crushes, (after export QT_DEBUG_PLUGINS=1) I get the following

                                QFactoryLoader::QFactoryLoader() checking directory path "/home/matteo/anaconda3/plugins/platforms" ...
                                QFactoryLoader::QFactoryLoader() looking at "/home/matteo/anaconda3/plugins/platforms/libqeglfs.so"
                                Found metadata in lib /home/matteo/anaconda3/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 "/home/matteo/anaconda3/plugins/platforms/libqminimal.so"
                                Found metadata in lib /home/matteo/anaconda3/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 "/home/matteo/anaconda3/plugins/platforms/libqminimalegl.so"
                                Found metadata in lib /home/matteo/anaconda3/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 "/home/matteo/anaconda3/plugins/platforms/libqoffscreen.so"
                                Found metadata in lib /home/matteo/anaconda3/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 "/home/matteo/anaconda3/plugins/platforms/libqvnc.so"
                                Found metadata in lib /home/matteo/anaconda3/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 "/home/matteo/anaconda3/plugins/platforms/libqwebgl.so"
                                Found metadata in lib /home/matteo/anaconda3/plugins/platforms/libqwebgl.so, metadata=
                                {
                                "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                "MetaData": {
                                "Keys": [
                                "webgl"
                                ]
                                },
                                "archreq": 0,
                                "className": "QWebGLIntegrationPlugin",
                                "debug": false,
                                "version": 330752
                                }

                                Got keys from plugin meta data ("webgl")
                                QFactoryLoader::QFactoryLoader() looking at "/home/matteo/anaconda3/plugins/platforms/libqxcb.so"
                                Found metadata in lib /home/matteo/anaconda3/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/matteo/anaconda3/bin/platforms" ...
                                Cannot load library /home/matteo/anaconda3/plugins/platforms/libqxcb.so: (/home/matteo/anaconda3/plugins/platforms/../../lib/libfontconfig.so.1: undefined symbol: FT_Done_MM_Var)
                                QLibraryPrivate::loadPlugin failed on "/home/matteo/anaconda3/plugins/platforms/libqxcb.so" : "Cannot load library /home/matteo/anaconda3/plugins/platforms/libqxcb.so: (/home/matteo/anaconda3/plugins/platforms/../../lib/libfontconfig.so.1: undefined symbol: FT_Done_MM_Var)"
                                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, minimal, minimalegl, offscreen, vnc, webgl, xcb.

                                The output of the command ls -l /usr/lib/x86_64-linux-gnu/libQt5Xcb* is

                                -rw-r--r-- 1 root root 1602 feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.prl
                                lrwxrwxrwx 1 root root 21 feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so -> libQt5XcbQpa.so.5.9.5
                                lrwxrwxrwx 1 root root 21 feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 -> libQt5XcbQpa.so.5.9.5
                                lrwxrwxrwx 1 root root 21 feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.9 -> libQt5XcbQpa.so.5.9.5
                                -rw-r--r-- 1 root root 1070840 feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.9.5

                                So, the point is that I do not have a deep knowledge of Ubuntu system in genreal, and I do not know if the problem is only with QT plugins or is elsewhere. The only thing I know is that the code itself is working fine in other machines, so the problem should not rely there.

                                Thanks if you can help me, let me know if you need any other information.

                                Thanks!

                                1 Reply Last reply
                                0
                                • SGaistS Offline
                                  SGaistS Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #96

                                  Hi and welcome to devnet,

                                  Your anaconda installation looks unusual, how did you do it ?

                                  Interested in AI ? www.idiap.ch
                                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                  1 Reply Last reply
                                  0
                                  • M Offline
                                    M Offline
                                    MBat
                                    wrote on last edited by
                                    #97

                                    Thanks for the welcome!

                                    I actually don't remember anything particular from the installation of Anaconda. But it has been 3 years ago, so I might have forgotten.
                                    Why do you say that it looks unusual?

                                    1 Reply Last reply
                                    0
                                    • SGaistS Offline
                                      SGaistS Offline
                                      SGaist
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #98

                                      @MBat said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                                      anaconda3/plugins/platforms/libqxcb.so

                                      Usually conda environments are not located at that level. That's what I find suspicious. But I have essentially used miniconda rather than the full Anaconda.

                                      Your main issue is that there's something wrong with your libfontconfig library.

                                      Interested in AI ? www.idiap.ch
                                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                      1 Reply Last reply
                                      0
                                      • M Matriarch

                                        @Lengendary This is working solution for me, thank you

                                        sudo apt-get install libxcb-xinerama0

                                        V Offline
                                        V Offline
                                        Violet Giraffe
                                        wrote on last edited by Violet Giraffe
                                        #99

                                        @Matriarch, thank you,

                                        sudo apt-get install libxcb-xinerama0
                                        

                                        worked for me on Ubuntu 20.04. Shame one has to scroll so deep down into the discussion before finding the answer.

                                        Also, I recently spent a lot of time getting a Qt application to run in a Github Actions VM - I was battling the xcb errors. Here's the complete list of things that needed to be installed:

                                        sudo apt-get install -qq libglu1-mesa-dev libx11-xcb-dev '^libxcb*'
                                        
                                        ali-aydinA 1 Reply Last reply
                                        1
                                        • S Offline
                                          S Offline
                                          sonamde
                                          wrote on last edited by
                                          #100

                                          @Lengendary said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                                          libxcb-xinerama0

                                          I am also facing the same issue :
                                          Got keys from plugin meta data ("xcb")
                                          QFactoryLoader::QFactoryLoader() checking directory path "/qfs/people/deso666/.conda/envs/particle/bin/platforms" ...
                                          Cannot load library /qfs/people/deso666/.conda/envs/particle/lib/python3.6/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (/share/apps/python/anaconda3.2019.3/lib/libQt5XcbQpa.so.5: symbol _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform, version Qt_5_PRIVATE_API not defined in file libQt5Gui.so.5 with link time reference)
                                          QLibraryPrivate::loadPlugin failed on "/qfs/people/deso666/.conda/envs/particle/lib/python3.6/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /qfs/people/deso666/.conda/envs/particle/lib/python3.6/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (/share/apps/python/anaconda3.2019.3/lib/libQt5XcbQpa.so.5: symbol _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform, version Qt_5_PRIVATE_API not defined in file libQt5Gui.so.5 with link time reference)"
                                          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.

                                          sh: line 1: 26241 Aborted (core dumped) python gui_annotation.py

                                          Then I ran:

                                          user$ cd /qfs/people/deso666/.conda/envs/particle/lib/python3.6/site-packages/PyQt5/Qt/plugins/platforms/
                                          user$ ldd libqxcb.so
                                          ./libqxcb.so: /share/apps/python/anaconda3.2019.3/lib/libQt5Core.so.5: version `Qt_5.13' not found (required by ./libqxcb.so)
                                          linux-vdso.so.1 => (0x00007ffd83f66000)
                                          libQt5XcbQpa.so.5 => /share/apps/python/anaconda3.2019.3/lib/libQt5XcbQpa.so.5 (0x00007fcf99cc3000)
                                          libfontconfig.so.1 => /share/apps/python/anaconda3.2019.3/lib/libfontconfig.so.1 (0x00007fcf99a7e000)
                                          libfreetype.so.6 => /share/apps/python/anaconda3.2019.3/lib/libfreetype.so.6 (0x00007fcf999d2000)
                                          libz.so.1 => /share/apps/python/anaconda3.2019.3/lib/libz.so.1 (0x00007fcf999b2000)
                                          libQt5Gui.so.5 => /share/apps/python/anaconda3.2019.3/lib/libQt5Gui.so.5 (0x00007fcf995e5000)
                                          libQt5DBus.so.5 => /share/apps/python/anaconda3.2019.3/lib/libQt5DBus.so.5 (0x00007fcf99585000)
                                          libQt5Core.so.5 => /share/apps/python/anaconda3.2019.3/lib/libQt5Core.so.5 (0x00007fcf9916e000)
                                          libGL.so.1 => /usr/lib64/libGL.so.1 (0x00007fcf98efb000)
                                          libpthread.so.0 => /usr/lib64/libpthread.so.0 (0x00007fcf98cdf000)
                                          libX11-xcb.so.1 => /share/apps/python/anaconda3.2019.3/lib/libX11-xcb.so.1 (0x00007fcf98cda000)
                                          libxcb.so.1 => /share/apps/python/anaconda3.2019.3/lib/libxcb.so.1 (0x00007fcf98ab0000)
                                          libXrender.so.1 => /usr/lib64/libXrender.so.1 (0x00007fcf988a5000)
                                          libXext.so.6 => /share/apps/python/anaconda3.2019.3/lib/libXext.so.6 (0x00007fcf98890000)
                                          libX11.so.6 => /share/apps/python/anaconda3.2019.3/lib/libX11.so.6 (0x00007fcf9874c000)
                                          libm.so.6 => /usr/lib64/libm.so.6 (0x00007fcf9844a000)
                                          libxkbcommon-x11.so.0 => /usr/lib64/libxkbcommon-x11.so.0 (0x00007fcf98242000)
                                          libxkbcommon.so.0 => /usr/lib64/libxkbcommon.so.0 (0x00007fcf98001000)
                                          libdl.so.2 => /usr/lib64/libdl.so.2 (0x00007fcf97dfd000)
                                          libstdc++.so.6 => /share/apps/python/anaconda3.2019.3/lib/libstdc++.so.6 (0x00007fcf97cbc000)
                                          libgcc_s.so.1 => /share/apps/python/anaconda3.2019.3/lib/libgcc_s.so.1 (0x00007fcf97ca7000)
                                          libc.so.6 => /usr/lib64/libc.so.6 (0x00007fcf978e4000)
                                          libgthread-2.0.so.0 => /share/apps/python/anaconda3.2019.3/lib/./libgthread-2.0.so.0 (0x00007fcf978df000)
                                          librt.so.1 => /usr/lib64/librt.so.1 (0x00007fcf976d6000)
                                          libglib-2.0.so.0 => /share/apps/python/anaconda3.2019.3/lib/./libglib-2.0.so.0 (0x00007fcf975b9000)
                                          libXi.so.6 => /usr/lib64/libXi.so.6 (0x00007fcf973a9000)
                                          libxml2.so.2 => /share/apps/python/anaconda3.2019.3/lib/./libxml2.so.2 (0x00007fcf9723e000)
                                          libuuid.so.1 => /share/apps/python/anaconda3.2019.3/lib/./libuuid.so.1 (0x00007fcf9703a000)
                                          libpng16.so.16 => /share/apps/python/anaconda3.2019.3/lib/./libpng16.so.16 (0x00007fcf97000000)
                                          libdbus-1.so.3 => /share/apps/python/anaconda3.2019.3/lib/./libdbus-1.so.3 (0x00007fcf96fac000)
                                          libicui18n.so.58 => /share/apps/python/anaconda3.2019.3/lib/./libicui18n.so.58 (0x00007fcf96b37000)
                                          libicuuc.so.58 => /share/apps/python/anaconda3.2019.3/lib/./libicuuc.so.58 (0x00007fcf96788000)
                                          libicudata.so.58 => /share/apps/python/anaconda3.2019.3/lib/./libicudata.so.58 (0x00007fcf94c88000)
                                          /lib64/ld-linux-x86-64.so.2 (0x0000565509dbb000)
                                          libexpat.so.1 => /share/apps/python/anaconda3.2019.3/lib/libexpat.so.1 (0x00007fcf94c54000)
                                          libxcb-dri3.so.0 => /share/apps/python/anaconda3.2019.3/lib/libxcb-dri3.so.0 (0x00007fcf94a4e000)
                                          libxcb-present.so.0 => /share/apps/python/anaconda3.2019.3/lib/libxcb-present.so.0 (0x00007fcf9484b000)
                                          libxcb-sync.so.1 => /share/apps/python/anaconda3.2019.3/lib/libxcb-sync.so.1 (0x00007fcf94644000)
                                          libxshmfence.so.1 => /usr/lib64/libxshmfence.so.1 (0x00007fcf94440000)
                                          libglapi.so.0 => /usr/lib64/libglapi.so.0 (0x00007fcf94211000)
                                          libselinux.so.1 => /usr/lib64/libselinux.so.1 (0x00007fcf93fea000)
                                          libXdamage.so.1 => /usr/lib64/libXdamage.so.1 (0x00007fcf93de6000)
                                          libXfixes.so.3 => /usr/lib64/libXfixes.so.3 (0x00007fcf93be0000)
                                          libxcb-glx.so.0 => /share/apps/python/anaconda3.2019.3/lib/libxcb-glx.so.0 (0x00007fcf939c4000)
                                          libxcb-dri2.so.0 => /share/apps/python/anaconda3.2019.3/lib/libxcb-dri2.so.0 (0x00007fcf937be000)
                                          libXxf86vm.so.1 => /usr/lib64/libXxf86vm.so.1 (0x00007fcf935b8000)
                                          libdrm.so.2 => /usr/lib64/libdrm.so.2 (0x00007fcf933a9000)
                                          libXau.so.6 => /usr/lib64/libXau.so.6 (0x00007fcf931a4000)
                                          libxcb-xkb.so.1 => /usr/lib64/libxcb-xkb.so.1 (0x00007fcf92f88000)
                                          libpcre.so.1 => /share/apps/python/anaconda3.2019.3/lib/././libpcre.so.1 (0x00007fcf92f3f000)
                                          liblzma.so.5 => /share/apps/python/anaconda3.2019.3/lib/././liblzma.so.5 (0x00007fcf92d19000)

                                          please help me.

                                          1 Reply Last reply
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