Comparing QString and char*

[SIFE]

I am trying to compare QString against char*, but I fail to do that:

void Register::checkKey()
{
    QMessageBox sd;
    QFile kFile("license.key");
    if (!kFile.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        sd.setText("The registration key doesn't exist.\n");
        sd.exec();
        exit(0);
    }
 
    QTextStream key(&kFile);
    QString test = key.readLine();
    kFile.close();
    QString hash = GetMacAddress();
    char ser[22];
    hdidnt(ser);
    QByteArray Id(ser);
    hash += QString::fromUtf8(Id);
    char *crypt = hash.toUtf8().data();
    encrypt(crypt, "key");
    MD5 md;
    if (test != QString::fromUtf8(md.digestString(md.digestString(md.digestString(crypt)))))
    {
        QMessageBox sdf;
        sdf.setText(QString::fromUtf8(md.digestString(md.digestString(md.digestString(crypt)))) + "\n" \
                  + test + "\n" \
                  + QString::number(sizeof(test.toUtf8())) + "\n" \
                    );
        sdf.exec();
        sd.setText("This product must have a valid key.\n");
        sd.exec();
        KeyDialog kDialog;
        kDialog.setKey(QString::fromUtf8(md.digestString(crypt)));
        kDialog.exec();
        exit(0);
    }
 
}

void Register::checkKey()
{
    QMessageBox sd;
    QFile kFile("license.key");
    if (!kFile.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        sd.setText("The registration key doesn't exist.\n");
        sd.exec();
        exit(0);
    }

    QTextStream key(&kFile);
    QString test = key.readLine();
    kFile.close();
    QString hash = GetMacAddress();
    char ser[22];
    hdidnt(ser);
    QByteArray Id(ser);
    hash += QString::fromUtf8(Id);
    char *crypt = hash.toUtf8().data();
    encrypt(crypt, "key");
    MD5 md;
    if (test != QString::fromUtf8(md.digestString(md.digestString(md.digestString(crypt)))))
    {
        QMessageBox sdf;
        sdf.setText(QString::fromUtf8(md.digestString(md.digestString(md.digestString(crypt)))) + "\n" \
                  + test + "\n" \
                  + QString::number(sizeof(test.toUtf8())) + "\n" \
                    );
        sdf.exec();
        sd.setText("This product must have a valid key.\n");
        sd.exec();
        KeyDialog kDialog;
        kDialog.setKey(QString::fromUtf8(md.digestString(crypt)));
        kDialog.exec();
        exit(0);
    }

}

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I tryied also to convert QString to char* then make the comparison but I fail too. Both QString test and md.digestString(md.digestString(md.digestString(cr ypt))) return some value but they unenable to compare.

[cincirin]

I would write something like this ...

QByteArray cryptByteArray = hash.toUtf8();
char *crypt = cryptByteArray.data();

QByteArray cryptByteArray = hash.toUtf8();
char *crypt = cryptByteArray.data();

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If you write directly

char *crypt = hash.toUtf8().data();

char *crypt = hash.toUtf8().data();

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then temporary QByteArray will no longer exists and "crypt" will point to dangled pointer.

[wysota]

Be sure to discard the newline character in case there is one in the file.

[SIFE]

Thenks Mr cincirin, it works now.