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Segmentation fault (core dumped) on my application

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  • Hamed.MasafiH Hamed.Masafi

    Convert

    locate = QApplication::arguments().at(0);
    

    to

    locate = a.arguments().at(0);
    

    and test.
    And your app must be started with at least one argument.

    R Offline
    R Offline
    Renn
    wrote on last edited by
    #11

    @Hamed.Masafi Not the same between a variable with QApplication? I've done it but to no avail.

    1 Reply Last reply
    0
    • Hamed.MasafiH Offline
      Hamed.MasafiH Offline
      Hamed.Masafi
      wrote on last edited by
      #12

      @Renn No, they are not same. The a with qApp and QApplication::instance() is equal.
      Can you please paste full source (main.cpp, ui_class.cpp and ui_class.h) ?

      Remote object sharing (OO RPC)
      http://forum.qt.io/topic/60680/remote-object-sharing-oo-rpc-solved

      Advanced, Powerful and easy to use ORM for Qt5
      https://forum.qt.io/topic/67417/advanced-powerful-and-easy-to-use-orm-for-qt5

      R 1 Reply Last reply
      0
      • R Renn

        @jsulm The point? I do not understand. I have found a mistake, when I delete this code yes no notification Segmentation, but formnya appears twice, the first has entered the root through pkexec, the other is there anything in the gui.
        I mean the following code:
        ui->browse->setIcon(icon);
        ui->browse->setIconSize(pix.size());

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #13

        @Renn Well, I think if you don't call ui->setupUi(this) then ui->browse will probably be null and you just dereference a null pointer which leads to the segmentation fault.
        ui->setupUi(this) initializes all the stuff in ui.

        if(getuid() > 0){
        // Here you do not call ui->setupUi(this);!
        pkexec.start("pkexec " + locate);
        pkexec.waitForFinished();
        }
        else{
        ui->setupUi(this);
        }
        

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

        R 1 Reply Last reply
        0
        • jsulmJ jsulm

          @Renn Well, I think if you don't call ui->setupUi(this) then ui->browse will probably be null and you just dereference a null pointer which leads to the segmentation fault.
          ui->setupUi(this) initializes all the stuff in ui.

          if(getuid() > 0){
          // Here you do not call ui->setupUi(this);!
          pkexec.start("pkexec " + locate);
          pkexec.waitForFinished();
          }
          else{
          ui->setupUi(this);
          }
          
          R Offline
          R Offline
          Renn
          wrote on last edited by
          #14

          @jsulm What should I do now? If I put ui-> setupUi (this); before and after, there are still some more than one, the other one did not go through pkexec root, while the other was entering through pkexec root.

          jsulmJ 1 Reply Last reply
          0
          • Hamed.MasafiH Hamed.Masafi

            @Renn No, they are not same. The a with qApp and QApplication::instance() is equal.
            Can you please paste full source (main.cpp, ui_class.cpp and ui_class.h) ?

            R Offline
            R Offline
            Renn
            wrote on last edited by
            #15

            @Hamed.Masafi Oh not the same, this is code that really complete the form ui is just testing me so that the application can go through pkexec root. under the code themselves:
            untitled.h
            #ifndef UNTITLED_H
            #define UNTITLED_H
            #include <QMainWindow>

            namespace Ui {
            class untitled;
            }

            class untitled : public QMainWindow
            {
            Q_OBJECT

            public:
            explicit untitled(QWidget *parent = 0);
            ~untitled();

            private slots:

            private:
            Ui::untitled *ui;
            };
            #endif // UNTITLED_H

            untitled.cpp
            #include "untitled.h"
            #include "ui_untitled.h"
            #include <QProcess>
            #include <QDebug>
            #include <QFileDialog>
            extern QString locate;
            untitled::untitled(QWidget *parent) :
            QMainWindow(parent),
            ui(new Ui::untitled)
            {
            //ui->setupUi(this);
            qDebug() << getuid();
            QProcess pkexec;
            if(getuid() > 0){
            //ui->setupUi(this);
            pkexec.start("pkexec " + locate);
            pkexec.waitForFinished();
            ui->setupUi(this);
            }
            // else{
            // ui->setupUi(this);
            // }
            //Change button to Icon Image

            QPixmap pix("/home/rnd/untitled/image/image.ico");
            QIcon icon(pix);
            //ui->browse->setIcon(icon);
            //ui->browse->setIconSize(pix.size());
            

            }

            untitled::~untitled()
            {
            delete ui;
            }

            main.cpp
            #include "untitled.h"
            #include <QApplication>
            QString locate;
            int main(int argc, char *argv[])
            {
            QApplication a(argc, argv);
            locate = a.arguments().at(0);
            untitled w;
            w.show();

            return a.exec();
            

            }

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            0
            • Hamed.MasafiH Offline
              Hamed.MasafiH Offline
              Hamed.Masafi
              wrote on last edited by
              #16
              #include "untitled.h"
              #include "ui_untitled.h"
              #include <QProcess>
              #include <QDebug>
              #include <QFileDialog>
              extern QString locate;
              
              untitled::untitled(QWidget *parent) : QMainWindow(parent), ui(new Ui::untitled)
              {
              	qDebug() << getuid();
              	QProcess pkexec;
              	if(getuid() > 0){
              		//ui->setupUi(this);
              		pkexec.start("pkexec " + locate);
              		pkexec.waitForFinished();
              	}
              	
              	ui->setupUi(this);
              
              	//Change button to Icon Image
              	QPixmap pix("/home/rnd/untitled/image/image.ico");
              	QIcon icon(pix);
              	//ui->browse->setIcon(icon);
              	//ui->browse->setIconSize(pix.size());
              }
              

              Remote object sharing (OO RPC)
              http://forum.qt.io/topic/60680/remote-object-sharing-oo-rpc-solved

              Advanced, Powerful and easy to use ORM for Qt5
              https://forum.qt.io/topic/67417/advanced-powerful-and-easy-to-use-orm-for-qt5

              R 1 Reply Last reply
              0
              • Hamed.MasafiH Hamed.Masafi
                #include "untitled.h"
                #include "ui_untitled.h"
                #include <QProcess>
                #include <QDebug>
                #include <QFileDialog>
                extern QString locate;
                
                untitled::untitled(QWidget *parent) : QMainWindow(parent), ui(new Ui::untitled)
                {
                	qDebug() << getuid();
                	QProcess pkexec;
                	if(getuid() > 0){
                		//ui->setupUi(this);
                		pkexec.start("pkexec " + locate);
                		pkexec.waitForFinished();
                	}
                	
                	ui->setupUi(this);
                
                	//Change button to Icon Image
                	QPixmap pix("/home/rnd/untitled/image/image.ico");
                	QIcon icon(pix);
                	//ui->browse->setIcon(icon);
                	//ui->browse->setIconSize(pix.size());
                }
                
                R Offline
                R Offline
                Renn
                wrote on last edited by
                #17

                @Hamed.Masafi That's the same mas, will appear 2 form as I mentioned earlier..

                1 Reply Last reply
                0
                • R Renn

                  @jsulm What should I do now? If I put ui-> setupUi (this); before and after, there are still some more than one, the other one did not go through pkexec root, while the other was entering through pkexec root.

                  jsulmJ Offline
                  jsulmJ Offline
                  jsulm
                  Lifetime Qt Champion
                  wrote on last edited by
                  #18

                  @Renn You should explain better what you actually want to do. Why do you call ui->setupUi(this) only if getuid()>0?

                  if(getuid() > 0){
                  // Do you want to have an UI in this case?
                  pkexec.start("pkexec " + locate);
                  pkexec.waitForFinished();
                  }
                  else{
                  ui->setupUi(this);
                  }
                  

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

                  R 1 Reply Last reply
                  0
                  • Hamed.MasafiH Offline
                    Hamed.MasafiH Offline
                    Hamed.Masafi
                    wrote on last edited by
                    #19

                    Oh, you'r right, but what is getuid() ??

                    Remote object sharing (OO RPC)
                    http://forum.qt.io/topic/60680/remote-object-sharing-oo-rpc-solved

                    Advanced, Powerful and easy to use ORM for Qt5
                    https://forum.qt.io/topic/67417/advanced-powerful-and-easy-to-use-orm-for-qt5

                    jsulmJ 1 Reply Last reply
                    0
                    • jsulmJ jsulm

                      @Renn You should explain better what you actually want to do. Why do you call ui->setupUi(this) only if getuid()>0?

                      if(getuid() > 0){
                      // Do you want to have an UI in this case?
                      pkexec.start("pkexec " + locate);
                      pkexec.waitForFinished();
                      }
                      else{
                      ui->setupUi(this);
                      }
                      
                      R Offline
                      R Offline
                      Renn
                      wrote on last edited by
                      #20

                      @jsulm Actually I outsmart gui so that I can enter the root through the framework polkit using pkexec in QProcess. When I write code
                      ui->setupUi (this);
                      pkexec.start("pkexec" + locate);
                      pkexec.waitForFinished();
                      form it appears 2, I outsmart menggunakai if else, in part if I enter the command QProcess and else that I enter ui->setupUi(this);
                      When I was running in qt no anything, but when I run through the terminal, at that time I realized that my application that I made it crashes with a notice "Segmentation fault (core dumped)"

                      1 Reply Last reply
                      0
                      • Hamed.MasafiH Hamed.Masafi

                        Oh, you'r right, but what is getuid() ??

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

                        @Hamed.Masafi Get user ID (man getuid)

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

                        R 1 Reply Last reply
                        0
                        • jsulmJ jsulm

                          @Hamed.Masafi Get user ID (man getuid)

                          R Offline
                          R Offline
                          Renn
                          wrote on last edited by
                          #22

                          @jsulm Now I have to do?

                          1 Reply Last reply
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