Question

我正在尝试了解如何在完成GTK小部件时正确释放内存，例如，如果我需要创建和销毁许多小部件。但是，无论我尝试什么，valgrind似乎都表明内存泄漏。我已经查看了其他问题，包括列出GTK的valgrind抑制文件，但它没有改变结果。

以下是重现我的问题的最简单的代码段：

#include "gtk/gtk.h"

int main()
{
    GtkWidget * widget = gtk_fixed_new();
    g_object_ref(widget);
    g_object_ref_sink(widget); // remove floating reference, and own this object ourselves

    g_object_unref(widget);

    gtk_widget_destroy(widget);
}

我的期望是（在处理浮动引用之后），unref（）函数应该将引用计数减少到零，然后释放所有内存。我把gtk_widget_destroy（）放在那里以便进行测量，但我不确定它是否真的必要（并且它不会改变泄漏的大小）。

来自问题Memory Leaks in GTK hello_world program的valgrind命令G_SLICE=debug-blocks valgrind ./t3 --supression=~/Downloads/GNOME.supp的输出是

==10079== HEAP SUMMARY:
==10079==     in use at exit: 164,338 bytes in 847 blocks
==10079==   total heap usage: 1,380 allocs, 533 frees, 219,176 bytes allocated
==10079== 
==10079== LEAK SUMMARY:
==10079==    definitely lost: 0 bytes in 0 blocks
==10079==    indirectly lost: 0 bytes in 0 blocks
==10079==      possibly lost: 21,350 bytes in 174 blocks
==10079==    still reachable: 142,988 bytes in 673 blocks
==10079==         suppressed: 0 bytes in 0 blocks
==10079== Rerun with --leak-check=full to see details of leaked memory

我看过的其他文档是http://www.demko.ca/blog/posts/200705_gtkmm_refcoutning.txt和https://developer.gnome.org/gtk2/2.24/GtkObject.html

您可以使用

编译我的代码段

gcc -std=gnu99 `pkg-config --cflags gtk+-2.0` t3.c -o t3 `pkg-config --libs gtk+-2.0 gthread-2.0`

任何人都知道我错过了什么？我应该调用另一个函数来确保释放内存吗？

Answer 1

 - g_object_ref

  Increases ref count by one

 - g_object_unref

  Decreases ref count by one, if ref count == 0, the object is destroyed

 - g_object_ref_sink

  IF the object has a floating ref, it converts that reference to a normal ref (sinks it)
  ELSE it increases the ref count by one

 - All objects start with a floating ref count of 1

如需进一步阅读，我建议您查看以下文章：Introduction to Memory Management in GTK+

现在，继续您的示例，让我们看看函数调用及其执行的操作：

GtkWidget * widget = gtk_fixed_new(); //widget created with ref count of 1 | floating = true
g_object_ref(widget); // floating = true, ref count increased to 2
g_object_ref_sink(widget); // floating = false, ref count remains at 2

g_object_unref(widget); // floating = false, ref count decreases to 1

//No further unrefs, hello leak!

我希望能解释你的泄密，一定要阅读上面提到的文章。

Answer 2

g_object_is_floating是一个api调用，可用于查找gtk对象是否为浮点引用计数。以下是示例代码的链接： http://wikistack.com/managing-gtk-memorygui-application-interview-question/

如何正确（和有效）释放gtk小部件中的内存

2 个答案: