公共运营商新，私人运营商删除：获得C2248“不能访问私有成员”当使用新 [英] Public operator new, private operator delete: getting C2248 "can not access private member" when using new

问题描述

类有重载的操作符 new 和 delete 。 新是公开的，删除是私人的。

A class has overloaded operators new and delete. new is public, delete is private.

构造此类的实例，我得到以下错误：

When constructing an instance of this class, I get the following error:

pFoo = new Foo(bar)

example.cpp（1）：error C2248：'Foo：operator delete'：无法访问在类中声明的私有成员'Foo'

但是这里没有调用 delete 扭曲的编译器头脑？ ：）

But there's no call to delete here, so what is going on in the twisted mind of the compiler? :)

1. 错误的原因是什么？


2. 是否可以不使用成员 CreateInstance 函数来解决问题？

1. What is the reason for the error?
2. Is it possible to resolve the problem without resorting to a member CreateInstance function?

推荐答案

当你做 new Foo（） c $ c> operator new 被调用来分配内存，然后调用 Foo 的构造函数。如果该构造函数抛出，因为你不能访问已经分配的内存，C ++运行时会通过将它传递到相应的 operator delete 来处理它。这就是为什么你总是必须为每个运算符new 实现一个匹配的运算符delete ，这就是为什么它需要可访问。

When you do new Foo() then two things happen: First operator new is invoked to allocate memory, then a constructor for Foo is called. If that constructor throws, since you cannot access the memory already allocated, the C++ runtime will take care of it by passing it to the appropriate operator delete. That's why you always must implement a matching operator delete for every operator new you write and that's why it needs to be accessible.

作为出路，您可以将它们都设为私有，并从公共成员函数中调用 operator new create（））。

As a way out you could make both of them private and invoke operator new from a public member function (like create()).

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