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社区首页 >问答首页 >g++ Double Free或corruption...But How？

问g++ Double Free或corruption...But How？
EN

Stack Overflow用户
提问于 2010-07-01 06:48:22
回答 3查看 2.1K关注 0票数 2

我的代码似乎有问题，不知道你们能不能帮我定位问题……我试过使用gdb和valgrind，后者更有用，但我仍然无法修复我的bug。

下面是我的类的代码(这是我的缩小版本，但问题的主要本质仍然存在)：

/*向量.h */

代码语言：javascript
复制
template<typename _TYPE_, Int _SIZE_>
class Vec
{
  public:
             Vec(void);
             Vec(const Vec<_TYPE_,_SIZE_>& vec);
    virtual ~Vec(void);

    Boolean             operator==(const Vec<_TYPE_,_SIZE_>& vec ) const;
    Boolean             operator!=(const Vec<_TYPE_,_SIZE_>& vec ) const;  
    Boolean             operator< (const Vec<_TYPE_,_SIZE_>& vec ) const;
    Boolean             operator> (const Vec<_TYPE_,_SIZE_>& vec ) const;
    Boolean             operator<=(const Vec<_TYPE_,_SIZE_>& vec ) const;
    Boolean             operator>=(const Vec<_TYPE_,_SIZE_>& vec ) const;

    const _TYPE_&       operator[](const Int index) const;
    _TYPE_&             operator[](const Int index);

    Vec<_TYPE_,_SIZE_>  operator+ (const Vec<_TYPE_,_SIZE_>& vec) const;
    Vec<_TYPE_,_SIZE_>  operator- (const Vec<_TYPE_,_SIZE_>& vec) const;
    Vec<_TYPE_,_SIZE_>  operator* (const _TYPE_ val ) const;

    _TYPE_              operator* (const Vec<_TYPE_,_SIZE_>& vec) const;

    Vec<_TYPE_,_SIZE_>& operator+=(const Vec<_TYPE_,_SIZE_>& vec);
    Vec<_TYPE_,_SIZE_>& operator-=(const Vec<_TYPE_,_SIZE_>& vec);
    Vec<_TYPE_,_SIZE_>& operator*=(const _TYPE_ val );

  private:
    _TYPE_* __data;
};

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>::Vec(void)
{
  me.__data = new _TYPE_[_SIZE_];

  for(Int i = 0; i < _SIZE_; i++)
    me.__data[i] = 0;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>::Vec(const Vec<_TYPE_,_SIZE_>& vec)
{
  me.__data = new _TYPE_[_SIZE_];

  for(Int i = 0; i < _SIZE_; i++)
    me.__data[i] = vec[i];
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>::~Vec(void)
{
  printf("~Vec<%p>...", (void*)this);

  if(me.__data != NOTHING)
    delete[] me.__data;
}

/*******************************************************************************
* COMPARISON OPERATORS.
*******************************************************************************/

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator==(const Vec<_TYPE_,_SIZE_>& vec) const
{
  if(this == &vec)
    return true;

  for(Int i = 0; i < _SIZE_; i++)
    if(me.__data[i] != vec[i])
      return false;

  return true;
}

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator!=(const Vec<_TYPE_,_SIZE_>& vec) const
{
  return !(me == vec);
}

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator< (const Vec<_TYPE_,_SIZE_>& vec ) const
{
  if(this == &vec)
    return false;

  for(Int i = 0; i < _SIZE_; i++)
    if(me.__data[i] >= vec[i])
      return false;

  return true;
}

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator> (const Vec<_TYPE_,_SIZE_>& vec ) const
{
  if(this == &vec)
    return false;

  for(Int i = 0; i < _SIZE_; i++)
    if(me.__data[i] <= vec[i])
      return false;

  return true;
}

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator<=(const Vec<_TYPE_,_SIZE_>& vec ) const
{
  return !(me > vec);
}

template<typename _TYPE_, Int _SIZE_>
Boolean Vec<_TYPE_,_SIZE_>::operator>=(const Vec<_TYPE_,_SIZE_>& vec ) const
{
  return !(me < vec);
}

/*******************************************************************************
* ELEMENT ACCESSORS.
*******************************************************************************/

template<typename _TYPE_, Int _SIZE_>
const _TYPE_& Vec<_TYPE_,_SIZE_>::operator[](const Int index) const
{
  return me.__data[index];
}

template<typename _TYPE_, Int _SIZE_>
_TYPE_& Vec<_TYPE_,_SIZE_>::operator[](const Int index)
{
  return me.__data[index];
}


/*******************************************************************************
* ARITHMATICAL OPERATORS.
*******************************************************************************/

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_> Vec<_TYPE_,_SIZE_>::operator+ (const Vec<_TYPE_,_SIZE_>& vec) const
{
  Vec<_TYPE_,_SIZE_> tmp;

  for(Int i = 0; i < _SIZE_; i++)
    tmp[i] = me.__data[i] + vec[i];

  return tmp;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_> Vec<_TYPE_,_SIZE_>::operator- (const Vec<_TYPE_,_SIZE_>& vec) const
{
  Vec<_TYPE_,_SIZE_> tmp;

  for(Int i = 0; i < _SIZE_; i++)
    tmp[i] = me.__data[i] - vec[i];

  return tmp;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_> Vec<_TYPE_,_SIZE_>::operator* (const _TYPE_ val ) const
{
  Vec<_TYPE_,_SIZE_> tmp;

  for(Int i = 0; i < _SIZE_; i++)
    tmp[i] = me.__data[i] * val;

  return tmp;
}

template<typename _TYPE_, Int _SIZE_>
_TYPE_ Vec<_TYPE_,_SIZE_>::operator* (const Vec<_TYPE_,_SIZE_>& vec) const
{
  _TYPE_ tmp = 0;

  for(Int i = 0; i < _SIZE_; i++)
    tmp += me.__data[i] * vec[i];

  return tmp;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>& Vec<_TYPE_,_SIZE_>::operator+=(const Vec<_TYPE_,_SIZE_>& vec)
{
  for(Int i = 0; i < _SIZE_; i++)
    me.__data[i] = me.__data[i] + vec[i];

  return me;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>& Vec<_TYPE_,_SIZE_>::operator-=(const Vec<_TYPE_,_SIZE_>& vec)
{
  for(Int i = 0; i < _SIZE_; i++)
    me.__data[i] = me.__data[i] - vec[i];

  return me;
}

template<typename _TYPE_, Int _SIZE_>
Vec<_TYPE_,_SIZE_>& Vec<_TYPE_,_SIZE_>::operator*=(const _TYPE_ val )
{
  for(Int i = 0; i < _SIZE_; i++)
    me.__data[i] = me.__data[i] * val;

  return me;
}

/*******************************************************************************
********************************************************************************
**  3D Vector Class.
********************************************************************************
*******************************************************************************/

template<typename _TYPE_>
class Vec3 : public Vec<_TYPE_,3>
{
  public:
    Vec3(_TYPE_ x = 0, _TYPE_ y = 0, _TYPE_ z = 0);
    Vec3(const Vec<_TYPE_,3>& vec);
    ~Vec3(void);
};

#define Vec3_f  Vec3<Float>

template<typename _TYPE_>
Vec3<_TYPE_>::Vec3(_TYPE_ x, _TYPE_ y, _TYPE_ z)
{
  me[XYZ::X] = x;
  me[XYZ::Y] = y;
  me[XYZ::Z] = z;
}

template<typename _TYPE_>
Vec3<_TYPE_>::Vec3(const Vec<_TYPE_,3>& vec)
{
  me[XYZ::X] = vec[XYZ::X];
  me[XYZ::Y] = vec[XYZ::Y];
  me[XYZ::Z] = vec[XYZ::Z];
}

template<typename _TYPE_>
Vec3<_TYPE_>::~Vec3(void)
{

}

/*物理状态.h */

代码语言：javascript
复制
class PhysicalState
{
  public:
    PhysicalState(Vec3_f pos = Vec3_f(1,1,1), Vec3_f rot = Vec3_f(2,2,2), Vec3_f scale = Vec3_f(3,3,3));
    PhysicalState(const PhysicalState& phys);
    ~PhysicalState(void);

    PhysicalState& operator=(const PhysicalState& phys);

  //Private:
    Vec3_f position;
    Vec3_f rotation;
    Vec3_f scale;
};

/* PhysicalState.cpp */

代码语言：javascript
复制
PhysicalState::PhysicalState(Vec3_f pos, Vec3_f rot, Vec3_f scale)
{
  me.position = pos;
  me.rotation = rot;
  me.scale    = scale;
}

PhysicalState::PhysicalState(const PhysicalState& phys)
{
  me.position = phys.position;
  me.rotation = phys.rotation;
  me.scale    = phys.scale;
}

PhysicalState::~PhysicalState(void)
{

}

PhysicalState& PhysicalState::operator=(const PhysicalState& phys)
{
  if(this != &phys)
  {
    me.position = phys.position;
    me.rotation = phys.rotation;
    me.scale    = phys.scale;
  }

  return me;
}

/* Test.cpp */

代码语言：javascript
复制
int main(void)
{
  PhysicalState ps;

  return 0;
}

很抱歉这么长。下面是valgrind的输出：

代码语言：javascript
复制
darkdivine@darkdivine-laptop:~/Development/Projects/Engines/DarkDivine$ LD_LIBRARY_PATH=./Bin/Debug/ valgrind
--track-origins=yes --leak-check=full ./Bin/Debug/Test
    ==18549== Memcheck, a memory error detector
    ==18549== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
    ==18549== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
    ==18549== Command: ./Bin/Debug/Test
    ==18549== 
    ==18549== Invalid free() / delete / delete[]
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x4036B69: DarkDivine::PhysicalState::~PhysicalState() (PhysicalState.cpp:23)
    ==18549==    by 0x8048E77: main (Test.cpp:15)
    ==18549==  Address 0x4740128 is 0 bytes inside a block of size 12 free'd
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x8048E3B: main (Test.cpp:13)
    ==18549== 
    ==18549== Invalid free() / delete / delete[]
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x4036B77: DarkDivine::PhysicalState::~PhysicalState() (PhysicalState.cpp:23)
    ==18549==    by 0x8048E77: main (Test.cpp:15)
    ==18549==  Address 0x4740168 is 0 bytes inside a block of size 12 free'd
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x8048E04: main (Test.cpp:13)
    ==18549== 
    ==18549== Invalid free() / delete / delete[]
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x4036B9C: DarkDivine::PhysicalState::~PhysicalState() (PhysicalState.cpp:23)
    ==18549==    by 0x8048E77: main (Test.cpp:15)
    ==18549==  Address 0x47401a8 is 0 bytes inside a block of size 12 free'd
    ==18549==    at 0x40244D3: operator delete[](void*) (vg_replace_malloc.c:409)
    ==18549==    by 0x804905A: DarkDivine::Vec<float, 3>::~Vec() (Vector.h:91)
    ==18549==    by 0x8048FE3: DarkDivine::Vec3<float>::~Vec3() (Vector.h:282)
    ==18549==    by 0x8048DE2: main (Test.cpp:13)
    ==18549== 
    ==18549== 
    ==18549== HEAP SUMMARY:
    ==18549==     in use at exit: 36 bytes in 3 blocks
    ==18549==   total heap usage: 10 allocs, 10 frees, 120 bytes allocated
    ==18549== 
    ==18549== 12 bytes in 1 blocks are definitely lost in loss record 1 of 3
    ==18549==    at 0x402532E: operator new[](unsigned int) (vg_replace_malloc.c:299)
    ==18549==    by 0x804923C: DarkDivine::Vec<float, 3>::Vec() (Vector.h:72)
    ==18549==    by 0x8048F76: DarkDivine::Vec3<float>::Vec3(float, float, float) (Vector.h:265)
    ==18549==    by 0x40367F1: DarkDivine::PhysicalState::PhysicalState(DarkDivine::Vec3<float>, DarkDivine::Vec3<float>, DarkDivine::Vec3<float>) (PhysicalState.cpp:6)
    ==18549==    by 0x8048DD7: main (Test.cpp:13)
    ==18549== 
    ==18549== 12 bytes in 1 blocks are definitely lost in loss record 2 of 3
    ==18549==    at 0x402532E: operator new[](unsigned int) (vg_replace_malloc.c:299)
    ==18549==    by 0x804923C: DarkDivine::Vec<float, 3>::Vec() (Vector.h:72)
    ==18549==    by 0x8048F76: DarkDivine::Vec3<float>::Vec3(float, float, float) (Vector.h:265)
    ==18549==    by 0x403681A: DarkDivine::PhysicalState::PhysicalState(DarkDivine::Vec3<float>, DarkDivine::Vec3<float>, DarkDivine::Vec3<float>) (PhysicalState.cpp:6)
    ==18549==    by 0x8048DD7: main (Test.cpp:13)
    ==18549== 
    ==18549== 12 bytes in 1 blocks are definitely lost in loss record 3 of 3
    ==18549==    at 0x402532E: operator new[](unsigned int) (vg_replace_malloc.c:299)
    ==18549==    by 0x804923C: DarkDivine::Vec<float, 3>::Vec() (Vector.h:72)
    ==18549==    by 0x8048F76: DarkDivine::Vec3<float>::Vec3(float, float, float) (Vector.h:265)
    ==18549==    by 0x4036843: DarkDivine::PhysicalState::PhysicalState(DarkDivine::Vec3<float>, DarkDivine::Vec3<float>, DarkDivine::Vec3<float>) (PhysicalState.cpp:6)
    ==18549==    by 0x8048DD7: main (Test.cpp:13)
    ==18549== 
    ==18549== LEAK SUMMARY:
    ==18549==    definitely lost: 36 bytes in 3 blocks
    ==18549==    indirectly lost: 0 bytes in 0 blocks
    ==18549==      possibly lost: 0 bytes in 0 blocks
    ==18549==    still reachable: 0 bytes in 0 blocks
    ==18549==         suppressed: 0 bytes in 0 blocks
    ==18549== 
    ==18549== For counts of detected and suppressed errors, rerun with: -v
    ==18549== ERROR SUMMARY: 6 errors from 6 contexts (suppressed: 63 from 6)

提前感谢任何可以帮助我的人，这让我发疯！GD。

PS: me = (*this)；NOTHING = 0；

corruption
delete-operator
c++
free
EN

回答 3

Stack Overflow用户

回答已采纳

发布于 2010-07-01 07:03:05

向量类有一个指针成员，但没有定义赋值运算符。赋值发生在PhysicalState的构造函数中，您可以通过值传递向量。

使用std::vector或boost::array。请。

票数 7
EN

Stack Overflow用户

发布于 2010-07-01 07:03:27

您的Vec类似乎没有自定义赋值运算符。

自动生成的operator=()只会复制__data指针，而实际上应该复制该数组中的元素。如果只复制了指针，那么在赋值之后，两个Vec对象将包含相同的指针，从而导致您所看到的问题。

需要自定义赋值运算符的一个很好的提示是，您已经需要一个自定义复制构造函数和一个自定义析构函数。如果你需要其中一个，你通常也需要另外两个("rule of three")。

票数 4
EN

Stack Overflow用户

发布于 2010-07-01 07:07:45

PhysicalState使用Vec3，但赋值不是复制构造。

基于使用指针的Vec的Vec3没有定义赋值运算符，因此指针被复制到丢失指向原始未初始化的指针，并导致早期意外删除和后来的双重删除。

在vec/vec3上创建operator=()以匹配复制构造函数。

票数 2
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/3153966

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