Copying the file content

[sierdzio]

Yes, start() starts the thread, but it does not mean your writeData() is called. If that were true, you would see your qDebug() output, because it is not in any if conditions - it should be printed every time writeData() is called.

[deleted286]

@sierdzio yes you are right. I've called the function. Thread is working now. But copying issue does not work.

[sierdzio]

I don't know either, you have not shown any code or stated how you want it all to work... so all I can say is "read the docs" :D QThread has a nice example and detailed description: https://doc.qt.io/qt-5/qthread.html#details

[deleted286]

@sierdzio I just want, when writeData() thread is called, copy the contents into new txt.

[J.Hilk]

@suslucoder
QThread has a started signal you connect that signal to your slot

[deleted286]

@J-Hilk My thread has working now. But copying does not occur

[jsulm]

@suslucoder So, what does copy() return?

[deleted286]

@jsulm it returns nothing, Either true or false

[jsulm]

@suslucoder said in Copying the file content:

it returns nothing, Either true or false

?
It returns a boolean.
Again: what does it return?!

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

[J.Hilk]

@suslucoder then the function isn't called.

Please post what you actually have in your code, otherwise no-one will be able to help you

[deleted286]

@jsulm it returns false.

#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

[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).

[JonB]

@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?

[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 ?

[deleted286]

@sierdzio
They exists.

[JonB]

@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?

[deleted286]

@SGaist I fixed it

[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.

[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().

[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.