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Copying the file content

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copyfileqt5file readfile write
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  • sierdzioS Offline
    sierdzioS Offline
    sierdzio
    Moderators
    wrote on last edited by
    #21

    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).

    (Z(:^

    D 1 Reply Last reply
    1
    • D deleted286

      @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
      
      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on 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

        @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
        
        SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on 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
        4
        • sierdzioS sierdzio

          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 last edited by
          #24

          @sierdzio
          They exists.

          Ekran görüntüsü 2021-01-11 112331.png

          JonBJ sierdzioS 2 Replies Last reply
          0
          • JonBJ Offline
            JonBJ Offline
            JonB
            wrote on 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
            • SGaistS SGaist

              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 last edited by
              #26

              @SGaist I fixed it

              1 Reply Last reply
              0
              • D deleted286

                @sierdzio
                They exists.

                Ekran görüntüsü 2021-01-11 112331.png

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #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
                1
                • D deleted286

                  @sierdzio
                  They exists.

                  Ekran görüntüsü 2021-01-11 112331.png

                  sierdzioS Offline
                  sierdzioS Offline
                  sierdzio
                  Moderators
                  wrote on 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
                  1
                  • JonBJ JonB

                    @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 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.

                    jsulmJ 1 Reply Last reply
                    0
                    • D deleted286

                      @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.

                      jsulmJ Offline
                      jsulmJ Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on 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
                      • sierdzioS sierdzio

                        @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 last edited by
                        #31

                        @sierdzio I'll try it again thank you

                        D 1 Reply Last reply
                        0
                        • D deleted286

                          @sierdzio I'll try it again thank you

                          D Offline
                          D Offline
                          deleted286
                          wrote on last edited by
                          #32

                          @suslucoder it works. thank you

                          1 Reply Last reply
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