porting Gtk to Qt?

[mismael85]

hi everybody;
i have a problem in porting Gtk code to Qt ,i am using the following code.

control = location_gpsd_control_get_default();
    device = (LocationGPSDevice *)g_object_new(LOCATION_TYPE_GPS_DEVICE, NULL);
 
    g_object_set(G_OBJECT(control),
                 "preferred-method", LOCATION_METHOD_USER_SELECTED,
                 "preferred-interval", LOCATION_INTERVAL_DEFAULT,
                 NULL);
 
    g_signal_connect(control, "error-verbose", G_CALLBACK(on_error), loop);
    g_signal_connect(device, "changed", G_CALLBACK(on_changed), control);
    g_signal_connect(control, "gpsd-stopped", G_CALLBACK(on_stop), loop);

control = location_gpsd_control_get_default();
    device = (LocationGPSDevice *)g_object_new(LOCATION_TYPE_GPS_DEVICE, NULL);
    
    g_object_set(G_OBJECT(control),
                 "preferred-method", LOCATION_METHOD_USER_SELECTED,
                 "preferred-interval", LOCATION_INTERVAL_DEFAULT,
                 NULL);
    
    g_signal_connect(control, "error-verbose", G_CALLBACK(on_error), loop);
    g_signal_connect(device, "changed", G_CALLBACK(on_changed), control);
    g_signal_connect(control, "gpsd-stopped", G_CALLBACK(on_stop), loop);

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i got an error

invalid use of member (did you forget the '&' ?)

how can i use g_signal_connect in Qt application?