C++ 为什么我的共享\u ptr内存泄漏？

我试图使用C++11的std:：tr1:：shared_ptr来管理SDL_曲面指针。注意，我没有使用Boost。我已经为共享的ptr定义了一个deleter来使用SDL_FreeSurface

声明如下：

class Engine {
private:
  std::tr1::shared_ptr<SDL_Surface> _scr;
  std::tr1::shared_ptr<SDL_Surface> _bg;  

Valgrind结果：

==3648== 8 bytes in 2 blocks are definitely lost in loss record 16 of 292
==3648==    at 0x402A018: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x431FBE0: strdup (in /lib/libc-2.14.1.so)

==3648== 1 bytes in 1 blocks are definitely lost in loss record 1 of 292
==3648==    at 0x402A018: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x494A590: _XlcDefaultMapModifiers (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A99A: XSetLocaleModifiers (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4097CDB: ??? (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x4083868: SDL_VideoInit (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x40594D9: SDL_InitSubSystem (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x42C3212: (below main) (in /lib/libc-2.14.1.so)

==3648== 980 (68 direct, 912 indirect) bytes in 1 blocks are definitely lost in loss record 258 of 292
==3648==    at 0x402A102: realloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x49402A6: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x49407A2: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494212F: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x49429BA: _XlcCreateLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4965957: _XlcUtf8Loader (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A793: _XOpenLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A8F1: _XlcCurrentLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4097CDB: ??? (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x4083868: SDL_VideoInit (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x40594D9: SDL_InitSubSystem (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x42C3212: (below main) (in /lib/libc-2.14.1.so)

使用

--track origins=yes

运行valgrind，这样它就会显示泄漏内存的分配位置

---

您可能还希望使用

--leak check=full

和

--leak resolution=high

（尽管后者应该是默认值）

不要在

SDL\u SetVideoMode

返回的指针上调用

SDL\u FreeSurface

。当您调用

SDL\u Quit

时，它将被释放。请参阅“返回值”下的内容。这还远远不够。我们需要了解如何使用共享指针。什么对象持有它们，什么对象控制它们，等等。同样，在C++11中没有像

std:：tr1:：shared\u ptr

这样的东西；它只是std:：shared_ptr；TR1早于C++11，如果您使用的是C++11，则不应使用它。@Google:我没有试图回答您关于内存泄漏的问题。我只是告诉你，你的删除者在那种情况下是无效的。另外，如果删除了删除器，这意味着它将使用默认的删除器，这实际上只是对指针调用

delete

，这也是不应该的。C++11中的共享指针只是

std:：shared\u ptr

，not

std:：tr1:：Sharedptr

Valgrind可能会对泄漏的数据给出一些误报，因为在应用程序退出时它仍然被分配，但它只分配一次，而且永远不会增长。如果你看实际字节数（989字节），它几乎不足以成为一个表面或任何重要的数据结构。可能是一些内部SDL状态变量

template<typename T>
class SurfaceDeleter{ 
public:
  void operator() (T*& d) const {
    if(d){
      SDL_FreeSurface(d);
    }
  }
};

  SDL_BlitSurface(_bg.get(), nullptr, _scr.get(), nullptr);
  SDL_Flip(_scr.get());

==3648== 8 bytes in 2 blocks are definitely lost in loss record 16 of 292
==3648==    at 0x402A018: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x431FBE0: strdup (in /lib/libc-2.14.1.so)

==3648== 1 bytes in 1 blocks are definitely lost in loss record 1 of 292
==3648==    at 0x402A018: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x494A590: _XlcDefaultMapModifiers (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A99A: XSetLocaleModifiers (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4097CDB: ??? (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x4083868: SDL_VideoInit (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x40594D9: SDL_InitSubSystem (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x42C3212: (below main) (in /lib/libc-2.14.1.so)

==3648== 980 (68 direct, 912 indirect) bytes in 1 blocks are definitely lost in loss record 258 of 292
==3648==    at 0x402A102: realloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==3648==    by 0x49402A6: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x49407A2: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494212F: ??? (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x49429BA: _XlcCreateLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4965957: _XlcUtf8Loader (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A793: _XOpenLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x494A8F1: _XlcCurrentLC (in /usr/lib/libX11.so.6.3.0)
==3648==    by 0x4097CDB: ??? (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x4083868: SDL_VideoInit (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x40594D9: SDL_InitSubSystem (in /usr/lib/libSDL-1.2.so.0.11.3)
==3648==    by 0x42C3212: (below main) (in /lib/libc-2.14.1.so)