i can write to a file using QFile, but can not do it using QFile *, why?

[htroyo]

hello, i was creating a basic and create a private QFile * and QTextStream * in my class because i wanted to use them inside slots, but i realized that i was able to open, read and even create files but was not able to write to them, after some tests i decided to use a QFile inside every slot (read the file and write contents into a QTextEdit when a button is pressed, save the file when other button is clicked, etc) that is just used inside the function and then deleted, and i were able to write to files using the QFile, but not the QFile *, i will contine using QFile but i want to know why i cant write to files using a QFile *, thanks

[rsilva]

If you use QFile*, you're declaring a pointer, you need to use "new QFile()" to it works.
And open it with the option for writing ^^

[htroyo]

yes, i know it is a pointer, i used f->open(QFile:;WriteOnly) to open the file and declared the text stream to write, but it doesnt work, i have to use a QFile instead of QFile * because it doesnt write content

---

Added after 4 minutes:

... and file->error() returns QFile:;NoError

[ChrisW67]

Works fine:

#include <QtCore>
#include <QDebug>
 
int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);
 
 
    QFile *outFile = new QFile("out.txt");
    if (outFile->open(QIODevice::WriteOnly)) {
        outFile->write("See, it does get out!\n");
        outFile->close();
    }
    delete outFile;
 
    QFile *inFile = new QFile("out.txt");
    if (inFile->open(QIODevice::ReadOnly)) {
        QByteArray line = inFile->readLine();
        inFile->close();
        qDebug() << line;
    }
    delete inFile;
 
    return 0;
}

#include <QtCore>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);


    QFile *outFile = new QFile("out.txt");
    if (outFile->open(QIODevice::WriteOnly)) {
        outFile->write("See, it does get out!\n");
        outFile->close();
    }
    delete outFile;

    QFile *inFile = new QFile("out.txt");
    if (inFile->open(QIODevice::ReadOnly)) {
        QByteArray line = inFile->readLine();
        inFile->close();
        qDebug() << line;
    }
    delete inFile;

    return 0;
}

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gives

"See, it does get out!
"

"See, it does get out!
"

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So, the question becomes what are you doing wrong? Are you attempting to write a file somewhere you do not have permission (e.g. under Program Files on Windows)? Are you not writing or reading the file you think you are?

[high_flyer]

yes, i know it is a pointer, i used f->open(QFile:;WriteOnly) to open the file and declared the text stream to write,

... and file->error() returns QFile:;NoError

It looks like you didn't initialize the pointer as rsilva noted:

you need to use "new QFile()" to it works.