GdkWindow

  GdkDeviceManager *device_manager;
  GdkDevice *pointer;
  gint px, py;
  g_signal_emit (scroll_area, signals[VIEWPORT_CHANGED], 0,
                 new_viewport, old_viewport);

  if (scroll_area->priv->input_window == NULL)
    return;

  device_manager = gdk_display_get_device_manager (gtk_widget_get_display (scroll_area->priv->input_window));
  pointer = gdk_device_manager_get_client_pointer (device_manager);
  gdk_window_get_device_position (GDK_WINDOW(scroll_area->priv->input_window), pointer, &px, &py, NULL);


warning: passing argument 1 of 'gtk_widget_get_display' from incompatible pointer type [enabled by default]
In file included from /opt/gnome/include/gtk-3.0/gtk/gtkapplication.h:27:0,
                 from /opt/gnome/include/gtk-3.0/gtk/gtkwindow.h:33,
                 from /opt/gnome/include/gtk-3.0/gtk/gtkdialog.h:33,
                 from /opt/gnome/include/gtk-3.0/gtk/gtkaboutdialog.h:30,
                 from /opt/gnome/include/gtk-3.0/gtk/gtk.h:31,
                 from scrollarea.h:19,
                 from scrollarea.c:19:
/opt/gnome/include/gtk-3.0/gtk/gtkwidget.h:714:15: note: expected 'struct GtkWidget *' but argument is of type 'struct GdkWindow *'