int code = (int)gtk_object_get_data(GTK_OBJECT(item), "user-data");
int code = GPOINTER_TO_INT(gtk_object_get_data(GTK_OBJECT(item), "user-data"));
void special_menuitem(GtkMenuItem *item, gpointer data){    struct gui_data *inst = (struct gui_data *)data;    int code = (int)gtk_object_get_data(GTK_OBJECT(item), "user-data");    inst->back->special(inst->backhandle, code);}