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  1. Qt
  2. QTBUG-87852

Qt applications give a blank white window or segfault in TigerVNC

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Details

    • Bug
    • Resolution: Invalid
    • Not Evaluated
    • None
    • 5.9.5
    • None
    • Linux + TigerVNC
    • Linux/X11

    Description

       

      Qt applications fail to start up correctly in TigerVNC 1.7.0+dfsg-8ubuntu2 with fvwm 1:2.6.7-3 on an Ubuntu 18.04 system.

      The Qt version is really 5.9.5+dfsg-0ubuntu2.5.

      The problem is the window that (usually) comes up is solid white - no widgets are displayed.  The rest of the time, the application segfaults.

      keepassxc gives a white window, and seems puzzled about the display resolution.

      A simple Qt5 hello world also gives a white window.

      konsole segfaults.

      The hello world looks like:

      #include <QtWidgets/QApplication>
       #include <QtWidgets/QPushButton>
      
      int main( int argc, char **argv )
      
      { QApplication a( argc, argv ); QPushButton hello( "Hello world!", 0 ); hello.resize( 100, 30 ); hello.show(); return a.exec(); }
      

       

      The corresponding Makefile looks like:

      CPPFLAGS=-I/usr/include/x86_64-linux-gnu/qt5 -fPIC
       LDFLAGS=-lQt5Core -lQt5Widgets
      
      go: qt-hello-world
       ./qt-hello-world
      
      qt-hello-world: qt-hello-world.o
       g++ -o qt-hello-world qt-hello-world.o ${LDFLAGS}
      

       

      I'm attaching to png's of what the hello world (hello-world.png) and keepassxc (keepassxc.png) look like, as well as the tty output from keepassxc (keepassxc.txt).

       

      Thanks!

       

      Attachments

        1. qtdiag.txt
          5 kB
        2. keepassxc.txt
          15 kB
        3. keepassxc.png
          keepassxc.png
          0.7 kB
        4. hello-world.png
          hello-world.png
          0.4 kB
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            esabraha Eskil Abrahamsen Blomfeldt
            dstromberg Dan Stromberg
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            Dates

              Created:
              Updated:
              Resolved:

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