Question

所以......我正试图消除我的GTK + 3程序中的一些内存泄漏。我虽然回顾一些简单的例子来看看是否有一些我忘记的清理工具是个好主意，但文档中提供的hello_world程序也有漏洞。（下面的Valgrind输出）。

这些泄漏是否可以接受？如果是这样，我应该使用其他一些应用来调试GTK程序吗？

==13717== Memcheck, a memory error detector
==13717== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
==13717== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==13717== Command: ./a
==13717== 
Hello World
==13717== 
==13717== HEAP SUMMARY:
==13717==     in use at exit: 1,578,162 bytes in 11,614 blocks
==13717==   total heap usage: 45,699 allocs, 34,085 frees, 6,461,970 bytes allocated
==13717== 
==13717== LEAK SUMMARY:
==13717==    definitely lost: 2,560 bytes in 5 blocks
==13717==    indirectly lost: 6,656 bytes in 207 blocks
==13717==      possibly lost: 363,228 bytes in 1,937 blocks
==13717==    still reachable: 1,205,718 bytes in 9,465 blocks
==13717==         suppressed: 0 bytes in 0 blocks
==13717== Rerun with --leak-check=full to see details of leaked memory
==13717== 
==13717== For counts of detected and suppressed errors, rerun with: -v
==13717== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)

代码：

#include <gtk/gtk.h>

/* This is a callback function. The data arguments are ignored
 * in this example. More on callbacks below.
 */
static void
print_hello (GtkWidget *widget,
             gpointer   data)
{
  g_print ("Hello World\n");
}

static gboolean
on_delete_event (GtkWidget *widget,
                 GdkEvent  *event,
                 gpointer   data)
{
  /* If you return FALSE in the "delete_event" signal handler,
   * GTK will emit the "destroy" signal. Returning TRUE means
   * you don't want the window to be destroyed.
   *
   * This is useful for popping up 'are you sure you want to quit?'
   * type dialogs.
   */

  g_print ("delete event occurred\n");

  return TRUE;
}

int
main (int   argc,
      char *argv[])
{
  /* GtkWidget is the storage type for widgets */
  GtkWidget *window;
  GtkWidget *button;

  /* This is called in all GTK applications. Arguments are parsed
   * from the command line and are returned to the application.
   */
  gtk_init (&argc, &argv);

  /* create a new window, and set its title */
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "Hello");

  /* When the window emits the "delete-event" signal (which is emitted
   * by GTK+ in response to an event coming from the window manager,
   * usually as a result of clicking the "close" window control), we
   * ask it to call the on_delete_event() function as defined above.
   *
   * The data passed to the callback function is NULL and is ignored
   * in the callback function.
   */
  g_signal_connect (window, "delete-event", G_CALLBACK (on_delete_event), NULL);

  /* Here we connect the "destroy" event to the gtk_main_quit() function.
   *
   * This signal is emitted when we call gtk_widget_destroy() on the window,
   * or if we return FALSE in the "delete_event" callback.
   */
  g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

  /* Sets the border width of the window. */
  gtk_container_set_border_width (GTK_CONTAINER (window), 10);

  /* Creates a new button with the label "Hello World". */
  button = gtk_button_new_with_label ("Hello World");

  /* When the button receives the "clicked" signal, it will call the
   * function print_hello() passing it NULL as its argument.
   *
   * The print_hello() function is defined above.
   */
  g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);

  /* The g_signal_connect_swapped() function will connect the "clicked" signal
   * of the button to the gtk_widget_destroy() function; instead of calling it
   * using the button as its argument, it will swap it with the user data
   * argument. This will cause the window to be destroyed by calling
   * gtk_widget_destroy() on the window.
   */
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);

  /* This packs the button into the window. A GtkWindow inherits from GtkBin,
   * which is a special container that can only have one child
   */
  gtk_container_add (GTK_CONTAINER (window), button);

  /* The final step is to display this newly created widget... */
  gtk_widget_show (button);

  /* ... and the window */
  gtk_widget_show (window);

  /* All GTK applications must have a gtk_main(). Control ends here
   * and waits for an event to occur (like a key press or a mouse event),
   * until gtk_main_quit() is called.
   */
  gtk_main ();

  return 0;
}

Answer 1

这个答案来自同一问题的答案（现已解散的www.gtkforums.com）。

GTK +在分配和释放应用程序生命周期所需的内部缓冲区方面非常懒惰。例如，它可以在初始化期间为查找表分配存储器区域，这是应用程序生命周期所需的。 GTK +将永远不会解除分配。对于Valgrind来说，这看起来像是内存泄漏（从技术上来说），但是作为优化，GTK +不会释放它，因为它将在应用程序退出期间解除分配，因此不会出错。这就是您需要抑制文件的原因，以便Valgrind可以忽略这些文件。问题是您需要在大多数GTK +版本更改时更改这些。

抑制文件的存储库： https://github.com/dtrebbien/GNOME.supp

克隆存储库后，您可以使用＆＃34; make＆＃34;生成抑制文件（也包含glib，gdk和其他文件）。然后像这样将valgrind引用给他们：

valgrind ./a --suppression=/path/to/gtk3.supp

Answer 2

为了调试glib / gtk程序，我会使用这个命令：

G_SLICE=debug-blocks valgrind --tool=memcheck --leak-check=full <gtk program>

G_SLICE = debug-blocks将关闭gtk的高级内存管理，以允许valgrind显示正确的结果。

- leak-check = full将显示泄漏的内存块的堆栈跟踪。

您还可以使用--show-reachable = yes查看程序退出时尚未释放的所有内存块的堆栈跟踪。

还有一个massif valgrind工具可以跟踪内存使用情况，以显示程序的哪些部分使用的内存最多。

在地块下运行程序：

G_SLICE=always-malloc valgrind --tool=massif --detailed-freq=2 --max-snapshots=400 --num-callers=20 <gtk program>

显示结果：

ms_print massif.out.<pid>

Answer 3

代替 valgrind 的是“泄漏消毒剂”对我有用。

编译：

gcc -g -fsanitize=leak `pkg-config --cflags gtk+-3.0` hello_world.c `pkg-config --libs gtk+-3.0`

*注意 -fsanitize=leak 选项

运行：

./a.out

GTK hello_world计划中的内存泄漏

3 个答案: