C ++在构造函数初始化列表中获取类成员地址 [英] C++ Get class member address in constructor initialization list

问题描述

我遇到了内存冲突错误，我不知道它来自哪里. 我的问题是:我是否可以在构造函数初始化列表中获取类成员的地址，以便可以将其传递给需要对其进行引用的对象?

I'm having a memory violation error and I don't know where it comes from. My question is : am I allowed to get the address of a class member while inside the constructor initialization list so that I can pass it to an object that needs a reference to it ?

例如:

class A
{
};

class ReferencesA
{
    A * const pA;

    ReferencesA( A * ptrA ) : pA( ptrA ) { }
};

class B
{
    A a;

    ReferencesA referencesA;

    B() : referencesA( & a ) { }
};

构造函数初始化列表中的& a是安全的吗?在我看来确实如此，但事情并非总是能像我们期望的那样进行.

Is is safe to & a inside the constructor initialization list ? It seems to me that it would be, but things don't always work like we expect.

谢谢.

推荐答案

class B中基本成员的初始化顺序是a，然后是referencesA.那是因为它们在类声明中依次出现 . (如果有的话，它们在构造函数的初始化列表中出现的顺序无关紧要.)

The order of the initialisation of the base members in class B is a, then referencesA. That's because they appear in that order in the class declaration. (The order in which they appear, if at all, in the initialisation list in your constructor is not relevant.)

因此，使用&a初始化referencesA 是安全的，即使有点脆弱.对于您来说，&a是默认构造的成员a的地址.

So using &a to initialise referencesA is safe, if a little brittle. In your case, &a is the address of the default-constructed member a.

我建议不要像这样编码，以防有人更改您班级中成员的顺序.

I'd advise against coding like this in case someone changes the order of the members in your class.

这篇关于C ++在构造函数初始化列表中获取类成员地址的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！