QTcpSocket with specific source/local port

qtcpsocket_test.cpp

// UNIX includes
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <string.h>

// QT includes
#include <QCoreApplication>
#include <QTcpSocket>

// C++
#include <iostream>

#define SRC_PORT 12345

#define DST_PORT 80
#define HOST "www.google.com"

int socket_descriptor = -1;

bool createSocket()
{
    socket_descriptor = socket(AF_INET, SOCK_STREAM, 0);
    return (socket_descriptor > 0);
}

bool bindSocket()
{
    struct sockaddr_in src_addr;

    memset(&src_addr, 0, sizeof(src_addr));
    src_addr.sin_family = AF_INET;
    src_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    src_addr.sin_port = htons(SOURCE_PORT);

    int res = bind(socket_descriptor, (struct sockaddr *) &src_addr, sizeof(src_addr));

    return (res >= 0);
}

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

    QCoreApplication app(argc, argv);

    QTcpSocket qt_socket;

    if ( createSocket() )
    {
        if ( bindSocket() ) {
            // emit connectionok
            qt_socket.setSocketDescriptor(socket_descriptor, QAbstractSocket::SocketState::BoundState);
            qt_socket.connectToHost(HOST, DST_PORT);
        } else
            std::cout << "Error while creating socket: " << strerror(errno) << std::endl;
    } else
        std::cout << "Error while creating socket: " << strerror(errno) << std::endl;

    return app.exec();
}

Using QT_VERSION > 5 this can be achieved with

qt_socket.bind(SRC_PORT);