qint32 values into QByteArray

Drazz

Hello,

Im running this code with Desktop Qt 5.15.2 GCC 64 bit.

#include <QCoreApplication>
#include <QByteArray>
#include <QDebug>

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

    quint32 value = 0x11223344;

    QByteArray payload;
    payload.resize(4);

    qInfo() << "Payload size: " << payload.size();

    payload[0] = static_cast<quint8>((value & 0xFF000000) >> 24);
    payload[1] = static_cast<quint8>((value & 0x00FF0000) >> 16);
    payload[2] = static_cast<quint8>((value & 0x0000FF00) >> 8);
    payload[3] = static_cast<quint8>((value & 0x000000FF) );
    qInfo() << "Output: " << payload;

    qInfo() << "Expected hex: " << hex \
            << static_cast<quint8>((value & 0xFF000000) >> 24) \
            << static_cast<quint8>((value & 0x00FF0000) >> 16) \
            << static_cast<quint8>((value & 0x0000FF00) >> 8) \
            << static_cast<quint8>((value & 0x000000FF) );

    return a.exec();
}

Output:

Payload size:  4
Output:  "\x11\"3D"
Expected hex:  11 22 33 44

Why output and expected are not equal? How can I do to make output and expected equal?

J.Hilk

@Drazz said in qint32 values into QByteArray:

Why output and expected are not equal? How can I do to make output and expected equal?

representation issues of qDebug() and QByteArray.

use qInfo() << "Output: " << payload.toHex(' ');

btw you should use QDataStream

Drazz

@J-Hilk <3

ChrisW67

Further to @J-Hilk's response, the four bytes in the array map to the string you see:

Output:        \x11 \" 3  D   
Expected hex:  11   22 33 44

The backslash before the " is there because the output is designed to be a usable C++ string and you escape embedded quotes.