g_signal_connect＆amp;函数g_signal_connect_swapped

Question

我正在使用此tutorial进行GTK学习。该链接中的第二个示例使用两个函数：g_signal_connect和g_signal_connect_swapped。我没有看到调用这两个函数有任何不同，但我在gsignal.h中找到了以下内容（也可以找到here）：

    For example, this allows the shorter code:
    |[<!-- language="C" -->
    g_signal_connect_swapped (button, "clicked",
                              (GCallback) gtk_widget_hide, other_widget);
    ]|

    Rather than the cumbersome:
    |[<!-- language="C" -->
    static void
    button_clicked_cb (GtkButton *button, GtkWidget *other_widget)
    {
        gtk_widget_hide (other_widget);
    }

    …

    g_signal_connect (button, "clicked",
                      (GCallback) button_clicked_cb, other_widget);
    ]|

当我编译代码g_signal_connect_swapped替换为g_signal_connect时，程序将无法正常工作;但是，如果我做相反的事情，它仍然有效。谁能告诉我这两个功能有什么区别？另外，如果不想要混淆，最好总是使用g_signal_connect_swapped代替另一个吗？

编辑： “第二个例子”的代码：

    #include <gtk/gtk.h>

    static void
    print_hello (GtkWidget *widget,
                 gpointer   data)
    {
      g_print ("Hello World\n");
    }

    static void
    activate (GtkApplication *app,
              gpointer        user_data)
    {
      GtkWidget *window;
      GtkWidget *button;
      GtkWidget *button_box;

      window = gtk_application_window_new (app);
      gtk_window_set_title (GTK_WINDOW (window), "Window");
      gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);

      button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
      gtk_container_add (GTK_CONTAINER (window), button_box);

      button = gtk_button_new_with_label ("Hello World");
      g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
      g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
      gtk_container_add (GTK_CONTAINER (button_box), button);

      gtk_widget_show_all (window);
    }

    int
    main (int    argc,
          char **argv)
    {
      GtkApplication *app;
      int status;

      app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
      g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
      status = g_application_run (G_APPLICATION (app), argc, argv);
      g_object_unref (app);

      return status;
    }