C ++私有指针“泄漏"? [英] C++ private pointer "leaking"?

问题描述

我将创建一个类来保存一长串将传递给函数的参数.让我们使用这个较短的示例:

I'm going to create a class to hold a long list of parameters that will be passed to a function. Let's use this shorter example:

class ParamList{

public:
    ParamList(string& a_string);
    string& getString(); //returns my_string
private:
    string& my_string;
}

我的问题是这样的:my_string是私有的，但我正在返回对其的引用.这不是在C ++中称为私有指针泄漏之类的东西吗?这不是好的编程习惯吗?我希望getString的调用者能够获取引用并对其进行修改.

My question is this: my_string is private, yet I'm returning the reference to it. Isn't that called something like private pointer leaking in C++? Is this not good programming practice? I want callers of getString to be able to get the reference and also modify it.

请让我知道.

谢谢， 杰布

edit1:调用者将使用getString()并修改返回的字符串.

edit1: callers will use getString() and modify the string that was returned.

推荐答案

只要满足以下条件，恢复私有引用就可以了:

Returing a private reference is perfectly okay so long as:

A.这是一个const引用，并且您已记录了该引用何时可以无效或
B.该引用旨在进行修改(即std::vector<T>::operator[])

A. That is a const reference, and you have documented when that reference can be invalidated or
B. That reference is intended to be modified (i.e. std::vector<T>::operator[])

虽然在返回非常量引用的情况下很有用，但通常应避免使用它. Scott Meyers的有效C ++ (第三版，条款28):如果您想看一下，请避免将句柄"返回给对象内部.

While there are useful cases for returning a non-const reference you should usually avoid it. This is covered in Scott Meyers' Effective C++ (3rd Edition, Item 28): Avoid returning "handles" to object internals, if you'd like to take a look.

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