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Copying the file content

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copyfileqt5file readfile write
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  • D deleted286
    11 Jan 2021, 08:18

    @jsulm it returns false. Ekran görüntüsü 2021-01-11 111741.png

    #include "mythread.h"
    #include "mainwindow.h"
    #include <QtCore>
    #include <QDebug>
    #include <QFile>
    #include <QTimer>
    #include <QThread>
    #include <QMutex>
    #include <QQueue>
    #include <QMessageBox>
    #include <QApplication>
    #include <QtWidgets/QApplication>
    #include <QtWidgets/QMainWindow>
    #include <QFileDialog>
    #include <QMainWindow>
    
    QFile file("C:/Users/ilknu/Documents/MyThread/deneme.txt");
    
    
    MyThread::MyThread(QObject* parent)
        : QThread(parent)
    {
        writeData();
    }
    
    MyThread::~MyThread()
    {
    
    }
    
    void MyThread::writeData()
    {
        QFile file2("C:/Users/ilknu/Documents/MyThread/new.txt");
        QFile::copy("C:/Users/ilknu/Documents/MyThread/deneme.txt","C:/Users/ilknu/Documents/MyThread/new.txt" );
        qDebug() << QFile::copy("C:/Users/user/Documents/MyThread/deneme.txt", "C:/Users/user/Documents/MyThread/new.txt");
        qDebug() << "im working in writing thread";
    
        emit writingDone();
    
    }
    
    void MyThread::run()  //Reading file from txt with thread1
    {
    
        if (file.open(QIODevice::ReadOnly))
        {
            QTextStream in (&file);
            while (!in.atEnd())
            {
                QString line = in.readAll();
                QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
                for(const QString &entry : list)
                {
                    double num = entry.toDouble();
                    queue.enqueue(num);
    
                }
    
    
                qDebug()<< "im running on worker thread " <<line;
    
            } // for
        } // while
        file.close();
    } // if
    
    J Offline
    J Offline
    JonB
    wrote on 11 Jan 2021, 08:21 last edited by
    #22

    @suslucoder
    Did you read the documentation of QFile::Copy() for yourself?

    Note that if a file with the name newName already exists, copy() returns false (i.e. QFile will not overwrite it).

    So, does the destination file already exist? Does the source file also exist?

    1 Reply Last reply
    1
    • D deleted286
      11 Jan 2021, 08:18

      @jsulm it returns false. Ekran görüntüsü 2021-01-11 111741.png

      #include "mythread.h"
      #include "mainwindow.h"
      #include <QtCore>
      #include <QDebug>
      #include <QFile>
      #include <QTimer>
      #include <QThread>
      #include <QMutex>
      #include <QQueue>
      #include <QMessageBox>
      #include <QApplication>
      #include <QtWidgets/QApplication>
      #include <QtWidgets/QMainWindow>
      #include <QFileDialog>
      #include <QMainWindow>
      
      QFile file("C:/Users/ilknu/Documents/MyThread/deneme.txt");
      
      
      MyThread::MyThread(QObject* parent)
          : QThread(parent)
      {
          writeData();
      }
      
      MyThread::~MyThread()
      {
      
      }
      
      void MyThread::writeData()
      {
          QFile file2("C:/Users/ilknu/Documents/MyThread/new.txt");
          QFile::copy("C:/Users/ilknu/Documents/MyThread/deneme.txt","C:/Users/ilknu/Documents/MyThread/new.txt" );
          qDebug() << QFile::copy("C:/Users/user/Documents/MyThread/deneme.txt", "C:/Users/user/Documents/MyThread/new.txt");
          qDebug() << "im working in writing thread";
      
          emit writingDone();
      
      }
      
      void MyThread::run()  //Reading file from txt with thread1
      {
      
          if (file.open(QIODevice::ReadOnly))
          {
              QTextStream in (&file);
              while (!in.atEnd())
              {
                  QString line = in.readAll();
                  QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
                  for(const QString &entry : list)
                  {
                      double num = entry.toDouble();
                      queue.enqueue(num);
      
                  }
      
      
                  qDebug()<< "im running on worker thread " <<line;
      
              } // for
          } // while
          file.close();
      } // if
      
      S Offline
      S Offline
      SGaist
      Lifetime Qt Champion
      wrote on 11 Jan 2021, 08:21 last edited by
      #23

      Hi,

      @suslucoder said in Copying the file content:

      QFile::copy("C:/Users/ilknu/Documents/MyThread/deneme.txt","C:/Users/ilknu/Documents/MyThread/new.txt" );
      qDebug() << QFile::copy("C:/Users/user/Documents/MyThread/deneme.txt", "C:/Users/user/Documents/MyThread/new.txt");

      You do not have the same paths in the qDebug and the previous line.
      You do realise that you are copying it twice ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      D 1 Reply Last reply 11 Jan 2021, 08:24
      4
      • S sierdzio
        11 Jan 2021, 08:20

        Check if it exists:

        qDebug() << "Source exists?" << QFile::exists("C:/Users/ilknu/Documents/MyThread/deneme.txt");
        qDebug() << "Destination exists?" << QFile::exists("C:/Users/ilknu/Documents/MyThread/new.txt");
        

        You need to check destination because:

        If a file with the name newName already exists, copy() returns false (i.e., QFile will not overwrite it).

        D Offline
        D Offline
        deleted286
        wrote on 11 Jan 2021, 08:24 last edited by
        #24

        @sierdzio
        They exists.

        Ekran görüntüsü 2021-01-11 112331.png

        J S 2 Replies Last reply 11 Jan 2021, 08:25
        0
        • J Offline
          J Offline
          JonB
          wrote on 11 Jan 2021, 08:24 last edited by
          #25

          @SGaist , @sierdzio , @J-Hilk
          If QFile::copy() returns false, I don't see anywhere the user can obtain any kind of error message/reason for the failure. Does Qt not supply this by any means?

          1 Reply Last reply
          0
          • S SGaist
            11 Jan 2021, 08:21

            Hi,

            @suslucoder said in Copying the file content:

            QFile::copy("C:/Users/ilknu/Documents/MyThread/deneme.txt","C:/Users/ilknu/Documents/MyThread/new.txt" );
            qDebug() << QFile::copy("C:/Users/user/Documents/MyThread/deneme.txt", "C:/Users/user/Documents/MyThread/new.txt");

            You do not have the same paths in the qDebug and the previous line.
            You do realise that you are copying it twice ?

            D Offline
            D Offline
            deleted286
            wrote on 11 Jan 2021, 08:24 last edited by
            #26

            @SGaist I fixed it

            1 Reply Last reply
            0
            • D deleted286
              11 Jan 2021, 08:24

              @sierdzio
              They exists.

              Ekran görüntüsü 2021-01-11 112331.png

              J Offline
              J Offline
              JonB
              wrote on 11 Jan 2021, 08:25 last edited by JonB 1 Nov 2021, 08:26
              #27

              @suslucoder said in Copying the file content:

              They exists.

              And? We have all said QFile::copy() says:

              Note that if a file with the name newName already exists, copy() returns false (i.e. QFile will not overwrite it).

              So you (not we) need to do something about that.

              Also, as @SGaist has pointed out, you don't even have the same paths on your two QFile::copy() calls.

              D 1 Reply Last reply 11 Jan 2021, 08:29
              1
              • D deleted286
                11 Jan 2021, 08:24

                @sierdzio
                They exists.

                Ekran görüntüsü 2021-01-11 112331.png

                S Offline
                S Offline
                sierdzio
                Moderators
                wrote on 11 Jan 2021, 08:29 last edited by
                #28

                @suslucoder

                Then the cause is clear: destination exists, so copy() will not overwrite it. You need to remove the destination file first, before calling copy().

                (Z(:^

                D 1 Reply Last reply 11 Jan 2021, 08:30
                1
                • J JonB
                  11 Jan 2021, 08:25

                  @suslucoder said in Copying the file content:

                  They exists.

                  And? We have all said QFile::copy() says:

                  Note that if a file with the name newName already exists, copy() returns false (i.e. QFile will not overwrite it).

                  So you (not we) need to do something about that.

                  Also, as @SGaist has pointed out, you don't even have the same paths on your two QFile::copy() calls.

                  D Offline
                  D Offline
                  deleted286
                  wrote on 11 Jan 2021, 08:29 last edited by
                  #29

                  @JonB said in Copying the file content:

                  Also, as @SGaist has pointed out, you don't even have the same paths on your two QFile::copy() calls. I've fixed it, it is my mistake.

                  Even i delete the destination file, for returning true by creating new destination, it returns false.

                  J 1 Reply Last reply 11 Jan 2021, 08:30
                  0
                  • D deleted286
                    11 Jan 2021, 08:29

                    @JonB said in Copying the file content:

                    Also, as @SGaist has pointed out, you don't even have the same paths on your two QFile::copy() calls. I've fixed it, it is my mistake.

                    Even i delete the destination file, for returning true by creating new destination, it returns false.

                    J Offline
                    J Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on 11 Jan 2021, 08:30 last edited by
                    #30

                    @suslucoder Did you check what @SGaist said? Do NOT call copy twice! Call it once like before but put qDebug() in front of it...

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

                    1 Reply Last reply
                    0
                    • S sierdzio
                      11 Jan 2021, 08:29

                      @suslucoder

                      Then the cause is clear: destination exists, so copy() will not overwrite it. You need to remove the destination file first, before calling copy().

                      D Offline
                      D Offline
                      deleted286
                      wrote on 11 Jan 2021, 08:30 last edited by
                      #31

                      @sierdzio I'll try it again thank you

                      D 1 Reply Last reply 11 Jan 2021, 08:52
                      0
                      • D deleted286
                        11 Jan 2021, 08:30

                        @sierdzio I'll try it again thank you

                        D Offline
                        D Offline
                        deleted286
                        wrote on 11 Jan 2021, 08:52 last edited by
                        #32

                        @suslucoder it works. thank you

                        1 Reply Last reply
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                        11 Jan 2021, 08:30

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