How can the htonl function in Qt be invoked?

In Qt, to call the htonl function, you can use the QSysInfo class to obtain the system’s byte order information, and then perform the appropriate conversion based on the byte order information.

Here is an example code that demonstrates how to use the htonl function for byte order conversion.

#include <QtGlobal>
#include <QSysInfo>
#include <QDebug>

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

    // 获取当前系统的字节序
    QSysInfo::ByteOrder byteOrder = QSysInfo::ByteOrder(QSysInfo::ByteOrder::LittleEndian);
    if (QSysInfo::ByteOrder::BigEndian == QSysInfo::currentByteOrder()) {
        byteOrder = QSysInfo::ByteOrder::BigEndian;
    }

    // 定义一个32位整数
    quint32 value = 0x12345678;

    // 如果系统字节序和网络字节序不一致，则进行转换
    if (byteOrder != QSysInfo::ByteOrder::BigEndian) {
        value = qToBigEndian(value);
    }

    // 输出转换后的结果
    qDebug() << "htonl value:" << value;

    return 0;
}

In the example above, the current byte order of the system is first obtained using the QSysInfo::currentByteOrder() function. The value to be converted is then converted to big-endian byte order (network byte order) using the qToBigEndian function, and the converted result is outputted. If the current system’s byte order is the same as the network byte order, no conversion will be done.

Please note that in Qt, there is also the qFromBigEndian function available for converting network byte order to host byte order (the byte order of the current system). The usage is similar, just reverse the direction of the byte order conversion.