使用基类指针删除派生类时发生内存泄漏 [英] memory leak when deleting derived class with base-class pointer

问题描述

我的内存泄漏有问题.我有一个基类的指针.从中，我使用new分配不同的派生类.然后，当我尝试使用引用delete这些类(未强制转换)时，出现内存泄漏.我研究了这个问题，发现我应该在基类中添加一个虚拟析构函数，但是我尝试了这一点，但仍然存在内存泄漏.也就是说，根据我的任务管理器，每次使用基类指针分配和删除派生类时，内存使用量将继续上升.我尝试使其成为抽象析构函数，并将析构函数添加到派生类，但出现未定义的引用错误.我还尝试将指针类型转换为delete的派生类指针，但是显然这会使程序崩溃.

I have an issue with a memory leak. I have a base-class pointer. From it, I use new to allocate different derived classes. Then, when I try to delete those classes with the reference (not typecasted), I get a memory leak. I researched the problem and found that I should add a virtual destructor to the base-class, but I tried this and I still have a memory leak; that is, according to my task-manager, the memory usage continues to rise with each allocation and deletion of the derived class using the base-class pointer. I tried making it an abstract destructor and added destructors to the derived classes, but I got an undefined reference error. I also tried typecasting the pointer as a derived-class pointer for the delete, but apparently this crashes the program.

有人知道我应该做什么吗?

Does anyone have any idea what I should do?

示例代码:

class A {
public:
  A();
  ~A() {};
  virtual ~A();      /*or*/
  virtual ~A()=0;    /*or*/
                     /*or nothing?*/
}

class B: private A {
public:
  B();
  ~B() {};           /*this?*/
                     /*or nothing?*/
}

推荐答案

使用virtual ~A();

如果允许使用virtual ~A()=0，我会感到惊讶.

I'd be surprised if virtual ~A()=0 is allowed.

使用以下代码:

A* base = new B();
delete base;

B的析构函数然后是A会被调用.

the destructor for B then A will be called.

如果您确实还在泄漏内存，那么其他地方还会泄漏.

If you're really still leaking memory, then you have another leak elsewhere.

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