gvcp

#include <QCoreApplication>
#include <QTcpSocket>
#include <QHostAddress>

#define GVCP_PORT 3956
#define GVCP_FLAG_REQUEST_ACK 0x0001

struct gvcp_header {
    quint16 flags;
    quint16 command;
    quint16 length;
    quint16 request_id;
};

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

    if (argc != 2) {
        qCritical("Usage: %s <camera IP address>", argv[0]);
        return 1;
    }

    const char *ip_addr = argv[1];

    QTcpSocket socket;
    socket.connectToHost(QHostAddress(ip_addr), GVCP_PORT);

    if (!socket.waitForConnected()) {
        qCritical("Failed to connect to the camera");
        return 1;
    }

    struct gvcp_header header;
    memset(&header, 0, sizeof(header));
    header.flags = qToBigEndian(GVCP_FLAG_REQUEST_ACK);
    header.command = qToBigEndian(0x0001); // read register command
    header.length = qToBigEndian(0x0004); // read 4 bytes
    header.request_id = qToBigEndian(0x0001);

    qint64 bytes_sent = socket.write(reinterpret_cast<const char*>(&header), sizeof(header));
    if (bytes_sent < 0) {
        qCritical("Failed to send data");
        return 1;
    }

    socket.waitForBytesWritten();

    struct gvcp_header response_header;
    memset(&response_header, 0, sizeof(response_header));

    if (socket.waitForReadyRead()) {
        qint64 bytes_received = socket.read(reinterpret_cast<char*>(&response_header), sizeof(response_header));
        if (bytes_received < 0) {
            qCritical("Failed to receive data");
            return 1;
        }
    }

    qDebug("Response header: flags=0x%04x command=0x%04x length=0x%04x request_id=0x%04x",
           qFromBigEndian(response_header.flags), qFromBigEndian(response_header.command),
           qFromBigEndian(response_header.length), qFromBigEndian(response_header.request_id));

    socket.close();

    return a.exec();
}