Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. QDBusConnection: systerm Dbus connection created before QCoreApplication
Qt 6.11 is out! See what's new in the release blog

QDBusConnection: systerm Dbus connection created before QCoreApplication

Scheduled Pinned Locked Moved Solved General and Desktop
20 Posts 5 Posters 9.6k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • A Offline
    A Offline
    Anny
    wrote on last edited by
    #9

    @mrjj @aha_1980 @SGaist Thank you, Ill define these as member variables and will get back to you.

    1 Reply Last reply
    0
    • SGaistS SGaist

      @aha_1980

      AFAIK, QString, QStringList and QList are not concerned as they have no dependencies on Qt's internal state. That said, I agree that all of these should be handled by the proper class.

      aha_1980A Offline
      aha_1980A Offline
      aha_1980
      Lifetime Qt Champion
      wrote on last edited by
      #10

      @SGaist said in QDBusConnection: systerm Dbus connection created before QCoreApplication:

      @aha_1980

      AFAIK, QString, QStringList and QList are not concerned as they have no dependencies on Qt's internal state.

      they don't contribute to the current problem, but may create other problems later.

      That said, I agree that all of these should be handled by the proper class.

      @Anny the reason is, that objects need to be constructed before usage. as a global variable, the time when their constructor runs is undefined. so it is possible, that you access variables before construction, which can even lead to crashes.

      Qt has to stay free or it will die.

      1 Reply Last reply
      0
      • A Offline
        A Offline
        Anny
        wrote on last edited by Anny
        #11

        Hi @aha_1980 as you said I just declared objects just before usage ,this error is gone . I also tried defining these objects in the header file of class ,there is no error.
        Edit: now there is no such warning/error but this code is not giving me status of wifi connection.I mean it should update status every 5 sec, but it just shows status of wifi in the very first iteration.
        I have a doubt I don't know If I can ask in the same thread, I have defined various variables,strings,structures in global.h file as external and I call them in different files. will this crash my application ?

        jsulmJ 1 Reply Last reply
        0
        • A Anny

          Hi @aha_1980 as you said I just declared objects just before usage ,this error is gone . I also tried defining these objects in the header file of class ,there is no error.
          Edit: now there is no such warning/error but this code is not giving me status of wifi connection.I mean it should update status every 5 sec, but it just shows status of wifi in the very first iteration.
          I have a doubt I don't know If I can ask in the same thread, I have defined various variables,strings,structures in global.h file as external and I call them in different files. will this crash my application ?

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #12

          @Anny Your

          while(true)
          

          loop is blocking Qt event loop. Remove it and use the asynchronous nature of Qt (you can use QTimer firing in 5 seconds intervals).

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

          1 Reply Last reply
          2
          • A Offline
            A Offline
            Anny
            wrote on last edited by
            #13

            @jsulm yeah i tried using timer but it not working i dont know why. I m using Timer in other classes , there it works fine. So i switched to thread::sleep

            1 Reply Last reply
            0
            • A Offline
              A Offline
              Anny
              wrote on last edited by
              #14

              @jsulm What I did is, I removed while(true) and sleep command and added timer
              connect(&check_network_timer,QTimer::timeout,this,&server_conneciton::run)
              check_network_timer.start(5000);
              This gives me nothing, app crashes after starting timer

              mrjjM 1 Reply Last reply
              0
              • A Anny

                @jsulm What I did is, I removed while(true) and sleep command and added timer
                connect(&check_network_timer,QTimer::timeout,this,&server_conneciton::run)
                check_network_timer.start(5000);
                This gives me nothing, app crashes after starting timer

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

                @Anny
                Hi
                Where does it crash ?
                You can use the debugger to see what is going on.
                Using timer normally do not crash so there must be some error in the code.

                1 Reply Last reply
                1
                • A Offline
                  A Offline
                  Anny
                  wrote on last edited by
                  #16

                  @mrjj I tried debugging it using debugger but it gives error box of segmentation fault saying signal received. what does it mean ?

                  mrjjM 1 Reply Last reply
                  0
                  • A Anny

                    @mrjj I tried debugging it using debugger but it gives error box of segmentation fault saying signal received. what does it mean ?

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by mrjj
                    #17

                    @Anny
                    Hi
                    It sounds like its crashing. ( segmentation faults = bad pointers, memory issues etc)
                    Place break point at top of function that timer calls etc and see if it stops.

                    1 Reply Last reply
                    1
                    • A Offline
                      A Offline
                      Anny
                      wrote on last edited by Anny
                      #18

                      @mrjj I added break points it does not stop. But when I run this class as QThread, app didnt crash but stuck after starting timer. I used moveToThread method to run it as thread. I also checked debugger and added some breakpoints, still not stopping and giving same segmentation fault. There is something I am missing out,I dont know what

                      mrjjM 1 Reply Last reply
                      0
                      • A Anny

                        @mrjj I added break points it does not stop. But when I run this class as QThread, app didnt crash but stuck after starting timer. I used moveToThread method to run it as thread. I also checked debugger and added some breakpoints, still not stopping and giving same segmentation fault. There is something I am missing out,I dont know what

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #19

                        @Anny

                        Hi
                        Do you start it with debug and not just normal run ?
                        It should stop.

                        1 Reply Last reply
                        2
                        • A Offline
                          A Offline
                          Anny
                          wrote on last edited by Anny
                          #20

                          @mrjj yeah i did it using debug mode. But I got this working now, there was some QThread related issue. Thank you so much everyone

                          1 Reply Last reply
                          2

                          • Login

                          • Login or register to search.
                          • First post
                            Last post
                          0
                          • Categories
                          • Recent
                          • Tags
                          • Popular
                          • Users
                          • Groups
                          • Search
                          • Get Qt Extensions
                          • Unsolved