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

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  • JonBJ JonB

    @Colins2
    From a terminal export QT_DEBUG_PLUGINS=1. Then type the full path to the Creator executable.

    C Offline
    C Offline
    Colins2
    wrote on last edited by
    #5

    @JonB Thanks.
    I tried that command and it worked partially.
    It found all the other plugins and it also found libqxcb.so, in the same folder, but couldn't load it.
    The spurious error message was:

    QFactoryLoader::QFactoryLoader() looking at "/home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so"
    Found metadata in lib /home/colins2/Qt/Tools/QtCreator/lib/Qt/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 "/home/colins2/Qt/Tools/QtCreator/bin/platforms" ...
    Cannot load library /home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)
    QLibraryPrivate::loadPlugin failed on "/home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/colins2/Qt/Tools/QtCreator/lib/Qt/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, xcb.

    Aborted

    I say spurious because it found the file and read it and then said it didn't exist, followed by "couldn't load.....even though it was found"
    Very puzzling

    JonBJ 1 Reply Last reply
    0
    • C Colins2

      @JonB Thanks.
      I tried that command and it worked partially.
      It found all the other plugins and it also found libqxcb.so, in the same folder, but couldn't load it.
      The spurious error message was:

      QFactoryLoader::QFactoryLoader() looking at "/home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so"
      Found metadata in lib /home/colins2/Qt/Tools/QtCreator/lib/Qt/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 "/home/colins2/Qt/Tools/QtCreator/bin/platforms" ...
      Cannot load library /home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so: (libxcb-util.so.1: cannot open shared object file: No such file or directory)
      QLibraryPrivate::loadPlugin failed on "/home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/colins2/Qt/Tools/QtCreator/lib/Qt/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, xcb.

      Aborted

      I say spurious because it found the file and read it and then said it didn't exist, followed by "couldn't load.....even though it was found"
      Very puzzling

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #6

      @Colins2
      Run ldd /home/colins2/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so. I think it's telling you it can't find a libxcb-util.so.1 required dependency, or another dependency of that.

      1 Reply Last reply
      2
      • C Offline
        C Offline
        Colins2
        wrote on last edited by
        #7

        @JonB
        Yes, that was it. ldd showed that I had libxcb-util.so.0 so I created a link in the same directory for libxcb-util.so.1 and now QtCreator is running.
        Many thanks for your help

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        • JonBJ JonB

          @Colins2
          From a terminal export QT_DEBUG_PLUGINS=1. Then type the full path to the Creator executable.

          D Offline
          D Offline
          deleted286
          wrote on last edited by
          #8

          @JonB said in qt.qpa.xcb: could not connect to display error:

          @Colins2
          From a terminal export QT_DEBUG_PLUGINS=1. Then type the full path to the Creator executable.

          I did this step but im getting this error still

          1 Reply Last reply
          0
          • C Colins2

            @JonB
            Yes, that was it. ldd showed that I had libxcb-util.so.0 so I created a link in the same directory for libxcb-util.so.1 and now QtCreator is running.
            Many thanks for your help

            D Offline
            D Offline
            deleted286
            wrote on last edited by
            #9

            @Colins2 how you created a link for it, libqxcb.so not found in my project

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            • D deleted286

              @Colins2 how you created a link for it, libqxcb.so not found in my project

              D Offline
              D Offline
              deleted286
              wrote on last edited by
              #10
              This post is deleted!
              1 Reply Last reply
              0
              • D deleted286

                @Colins2 how you created a link for it, libqxcb.so not found in my project

                C Offline
                C Offline
                Colins2
                wrote on last edited by Colins2
                #11

                @suslucoder
                Run the ldd command that JonB posted above and scroll through the list to try and find libxcb-util.so.?
                You seem to have a similar problem to me in that Qt can't find the shared library.
                ldd will show you where the libxcb file is. Qt wants version .so.1 and I had .so.0 and so it wouldn't run.
                It's probably best to try and find the newer version from your distro repo, which I will do sometime but just to try it out I created a link called libxcb-util.so.1 linked back to ver so.0 so that Qt could find it.

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                • C Colins2

                  @suslucoder
                  Run the ldd command that JonB posted above and scroll through the list to try and find libxcb-util.so.?
                  You seem to have a similar problem to me in that Qt can't find the shared library.
                  ldd will show you where the libxcb file is. Qt wants version .so.1 and I had .so.0 and so it wouldn't run.
                  It's probably best to try and find the newer version from your distro repo, which I will do sometime but just to try it out I created a link called libxcb-util.so.1 linked back to ver so.0 so that Qt could find it.

                  D Offline
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                  deleted286
                  wrote on last edited by
                  #12

                  @Colins2 it doesnt find it. I will figure it out

                  ldd: /home/ilknur/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so: No such file or directory
                  
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                  • D deleted286

                    @Colins2 it doesnt find it. I will figure it out

                    ldd: /home/ilknur/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so: No such file or directory
                    
                    C Offline
                    C Offline
                    Colins2
                    wrote on last edited by Colins2
                    #13

                    @suslucoder
                    libxcb-utils.so.* is not a Qt library so you may have to get it using your update tool.
                    Here's an excerpt from my system from the ldd command:
                    libxcb-icccm.so.4 => /lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007f11afec6000)
                    libxcb-image.so.0 => /lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007f11afcc1000)
                    libxcb-shm.so.0 => /lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007f11afcba000)
                    libxcb-util.so.1 => /lib/x86_64-linux-gnu/libxcb-util.so.1 (0x00007f11afab3000)
                    libxcb-keysyms.so.1 => /lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007f11af8b0000)
                    Obviously showing after the link I created.

                    1 Reply Last reply
                    1
                    • mrjjM mrjj

                      Hi
                      You mean run your project stand alone ?

                      Did you make a deployment folder for it ?

                      D Offline
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                      deleted286
                      wrote on last edited by
                      #14

                      @mrjj sorry i didnt see this answer. Im trying to run on qt creator. ı didnt deploy my project.

                      mrjjM 1 Reply Last reply
                      0
                      • D deleted286

                        @mrjj sorry i didnt see this answer. Im trying to run on qt creator. ı didnt deploy my project.

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #15

                        @suslucoder

                        Ok. Is this by any chance ubuntu 20.04 ?

                        sometimes people have to install libxcb-xinerama.so

                        sometimes more.

                        sudo apt-get install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev
                        sudo apt-get install libxkbcommon-x11-dev

                        https://forum.qt.io/topic/93247/qt-qpa-plugin-could-not-load-the-qt-platform-plugin-xcb-in-even-though-it-was-found/64

                        but please check with ldd first, what is actually missing.

                        D 1 Reply Last reply
                        1
                        • mrjjM mrjj

                          @suslucoder

                          Ok. Is this by any chance ubuntu 20.04 ?

                          sometimes people have to install libxcb-xinerama.so

                          sometimes more.

                          sudo apt-get install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev
                          sudo apt-get install libxkbcommon-x11-dev

                          https://forum.qt.io/topic/93247/qt-qpa-plugin-could-not-load-the-qt-platform-plugin-xcb-in-even-though-it-was-found/64

                          but please check with ldd first, what is actually missing.

                          D Offline
                          D Offline
                          deleted286
                          wrote on last edited by
                          #16

                          @mrjj I've solve this problem with setting ld library path in environment variables.
                          But now, it says it cannot find another lib, i really stuck on it

                          jsulmJ 1 Reply Last reply
                          0
                          • D deleted286

                            @mrjj I've solve this problem with setting ld library path in environment variables.
                            But now, it says it cannot find another lib, i really stuck on it

                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by jsulm
                            #17

                            @suslucoder said in qt.qpa.xcb: could not connect to display error:

                            i really stuck on it

                            You forgot to say which other lib is not found now...
                            Also, setting LD_LIBRARY_PATH is not necessary if all needed packages are installed properly.

                            Please take a look at https://doc.qt.io/qt-5/linux-requirements.html

                            https://forum.qt.io/topic/113070/qt-code-of-conduct

                            D 1 Reply Last reply
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                            • jsulmJ jsulm

                              @suslucoder said in qt.qpa.xcb: could not connect to display error:

                              i really stuck on it

                              You forgot to say which other lib is not found now...
                              Also, setting LD_LIBRARY_PATH is not necessary if all needed packages are installed properly.

                              Please take a look at https://doc.qt.io/qt-5/linux-requirements.html

                              D Offline
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                              deleted286
                              wrote on last edited by
                              #18

                              @jsulm when i run it on terminal
                              like

                              ./my app name
                              

                              there is no library that gives not found error

                              but when i tried to run it on qt creator it is give an error.
                              Other lib is that cannot found, libqmapcontrol.so.0
                              it is related with qmapcontrol

                              jsulmJ 1 Reply Last reply
                              0
                              • D deleted286

                                @jsulm when i run it on terminal
                                like

                                ./my app name
                                

                                there is no library that gives not found error

                                but when i tried to run it on qt creator it is give an error.
                                Other lib is that cannot found, libqmapcontrol.so.0
                                it is related with qmapcontrol

                                jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #19

                                @suslucoder said in qt.qpa.xcb: could not connect to display error:

                                qmapcontrol

                                How did you install it (and where)?

                                https://forum.qt.io/topic/113070/qt-code-of-conduct

                                D 1 Reply Last reply
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                                • jsulmJ jsulm

                                  @suslucoder said in qt.qpa.xcb: could not connect to display error:

                                  qmapcontrol

                                  How did you install it (and where)?

                                  D Offline
                                  D Offline
                                  deleted286
                                  wrote on last edited by
                                  #20

                                  @jsulm i have a folder named as library in my project folder.
                                  And i give a path for it my my .pro file.
                                  I dont know how it is installed, i take the project from who worked here before me.
                                  But it works perfect, till the day i tried to deploy.
                                  But i deployed it to another folder, i didnt touch the orijinal project

                                  jsulmJ 1 Reply Last reply
                                  0
                                  • D deleted286

                                    @jsulm i have a folder named as library in my project folder.
                                    And i give a path for it my my .pro file.
                                    I dont know how it is installed, i take the project from who worked here before me.
                                    But it works perfect, till the day i tried to deploy.
                                    But i deployed it to another folder, i didnt touch the orijinal project

                                    jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #21

                                    @suslucoder I think I already gave you this link: https://doc.qt.io/qt-5/linux-deployment.html

                                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    D 1 Reply Last reply
                                    0
                                    • jsulmJ jsulm

                                      @suslucoder I think I already gave you this link: https://doc.qt.io/qt-5/linux-deployment.html

                                      D Offline
                                      D Offline
                                      deleted286
                                      wrote on last edited by
                                      #22

                                      @jsulm yes you did but my problem is not about deploying.
                                      I cannot run my project on qt creator

                                      1 Reply Last reply
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