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    Solved Qt 5.15.2 do not build libqxcb.so, BUT at the same time Qt 5.14.0 successfully build libqxcb.so

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    • N
      nen777w last edited by nen777w

      Platform Ubuntu 18.04

      I built Qt 5.15.2 library but I can't use it because libxcb.so wich is should be at "qtbase/plugins/platforms/".
      When I start my application it filed:

      "qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
      This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
      
      Available platform plugins are: linuxfb, minimal, offscreen, vnc, webgl."
      

      Of course:
      I read this article: https://doc.qt.io/qt-5/linux-requirements.html
      And installed all necessary libraries (even more):

      sudo apt install libfontconfig1-dev libfreetype6-dev libx11-dev libx11-xcb-dev libxext-dev libxfixes-dev libxi-dev libxrender-dev libxcb1-dev libxcb-glx0-dev libxcb-keysyms1-dev libxcb-image0-dev libxcb-shm0-dev libxcb-icccm4-dev libxcb-sync-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-render-util0-dev libxkbcommon-dev libxkbcommon-x11-dev
      
      sudo apt-get install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev
      
      sudo apt install libfreetype6-dev libxext-dev libxfixes-dev libxi-dev libxrender-dev libxcb1-dev libx11-xcb-dev libxcb-glx0-dev libxkbcommon-x11-dev
      

      My Qt configuration:

      ./configure -prefix $PWD/qtbase -opensource -debug -skip qtwebengine -skip qtquickcontrols -skip qtconnectivity -skip qtwebglplugin -skip qtlocation -no-sql-odbc -no-sql-sqlite -no-icu -nomake examples -nomake tests -opengl desktop -platform linux-g++-64
      

      In configuration output I see the following:

      Checking for XCB >= 1.11... yes
      Checking for XCB ICCCM >= 0.3.9... yes
      Checking for XCB Util >= 0.3.9... no
      ...
      X11 specific:
          XLib ................................. no
          XCB Xlib ............................. no
          EGL on X11 ........................... no
          xkbcommon-x11 ........................ yes
      QPA backends:
        DirectFB ............................... no
        EGLFS .................................. no
        LinuxFB ................................ yes
        VNC .................................... yes
      

      At the same time, when I build Qt 5.14.0 the libxcb.so build successfully.

      The configuration output is following:

      Checking for XCB ICCCM >= 0.3.9... yes
      Checking for XCB SHM... yes
      Checking for XCB Image >= 0.3.9... yes
      Checking for XCB Keysyms >= 0.3.9... yes
      Checking for XCB RandR... yes
      Checking for XCB XRender... yes
      Checking for XCB Renderutil >= 0.3.9... yes
      Checking for XCB Shape... yes
      Checking for XCB Sync... yes
      Checking for XCB Xfixes... yes
      Checking for XCB Xinerama... yes
      Checking for XCB (extensions)... yes
      ...
      XCB:
          Using system-provided XCB libraries .. yes
          XCB XKB .............................. yes
          XCB XInput ........................... no
          Native painting (experimental) ....... no
          GL integrations:
            GLX Plugin ......................... no
            EGL-X11 Plugin ..................... no
      

      What changed? ​and
      How to fix that?

      1 Reply Last reply Reply Quote 0
      • N
        nen777w last edited by

        Seems like I fix the problem:

        sudo apt-get install libxcb-util-dev
        

        It required for build Qt 5.15.x but not required for Qt 5.14.x

        1 Reply Last reply Reply Quote 0
        • SGaist
          SGaist Lifetime Qt Champion last edited by

          Hi,

          Some in tree external libraries have been removed as all the officially supported distribution where providing the required library.

          You should check the test logs to see exactly which X11 related tests failed.

          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 Reply Quote 1
          • N
            nen777w last edited by

            @SGaist said in Qt 5.15.2 do not build libqxcb.so, BUT at the same time Qt 5.14.0 successfully build libqxcb.so:

            Hi,
            Some in tree external libraries have been removed as all the officially supported distribution where providing the required library.
            You should check the test logs to see exactly which X11 related tests failed.

            Could you please point me to where I can find the test logs?

            I just checked the sources and found that xcb is present in the source tree:
            /qt-everywhere-src-5.15.2/qtbase/src/plugins/platforms/xcb/

            1 Reply Last reply Reply Quote 0
            • N
              nen777w last edited by

              Seems like I fix the problem:

              sudo apt-get install libxcb-util-dev
              

              It required for build Qt 5.15.x but not required for Qt 5.14.x

              1 Reply Last reply Reply Quote 0
              • Christian Ehrlicher
                Christian Ehrlicher Lifetime Qt Champion last edited by

                @nen777w said in Qt 5.15.2 do not build libqxcb.so, BUT at the same time Qt 5.14.0 successfully build libqxcb.so:

                It required for build Qt 5.15.x but not required for Qt 5.14.x

                Correct as described here: https://doc.qt.io/qt-5/linux-requirements.html

                Note: From Qt 5.15 onwards, Qt does require libxcb 1.11. Also, the -qt-xcb configure option got removed that was bundling some of the libs below. Anyhow, you can now configure with -bundled-xcb-xinput to avoid a dependency to system xcb-xinput.

                Qt has to stay free or it will die.

                1 Reply Last reply Reply Quote 2
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