C++ 与 gcc 和 visual studio 的不同编译错误， 'within this context'

Question

我之前发过类似的问题，但是我的代码有一点小错误，所以忽略了，让我再问一次。

在 Gcc 中，我得到了编译错误的确切行 在 VS2010/2012 中我不知道编译错误在哪里，有人可以帮忙吗？ ** 在 VS 中，我怎么知道哪一行调用了它？

我有以下代码:

#include "ObjectHolder.h"

int main()
{
    ObjectHolder first(1);
    ObjectHolder second(first);
    return 0;
}
#ifndef NonCopyableObject_Included
#define NonCopyableObject_Included

class NonCopyableObject 
{
    public:
        virtual ~NonCopyableObject () {}

        NonCopyableObject(int i) { m_index = i;}
        int m_index;
        private:
        NonCopyableObject(const NonCopyableObject& other) {}
};
#endif

#ifndef ObjectHolder_Included
#define ObjectHolder_Included
#include "NonCopyableObject.h"

class ObjectHolder 
{
    public:
        virtual ~ObjectHolder ();
        ObjectHolder(int i) : obj(i) {}

        NonCopyableObject obj;
};
#endif

VS 错误:

1>d:\users\user\documents\visual studio 2012\projects\tester\tester\objectholder.h(13): 

     error C2248: 'NonCopyableObject::NonCopyableObject' : cannot access private member declared in   class 'NonCopyableObject'
               d:\users\user\documents\visual studio 2012\projects\tester\tester  
     \noncopyableobject.h(13) : see declaration of 'NonCopyableObject::NonCopyableObject'
            d:\users\user\documents\visual studio 2012\projects\tester\tester
     \noncopyableobject.h(6) : see declaration of 'NonCopyableObject'
            This diagnostic occurred in the compiler generated function    
     'ObjectHolder::ObjectHolder(const ObjectHolder &)'

海湾合作委员会:

$ g++ -Wall -Werror --std=c++0x main.cpp -o test_no_copy
In file included from main.cpp:2:0:

     NonCopyableObject.h: In copy constructor `ObjectHolder::ObjectHolder(const ObjectHolder&)':
     NonCopyableObject.h:13:3: error: `NonCopyableObject::NonCopyableObject(const NonCopyableObject&)' is private
     ObjectHolder.h:7:1: error: within this context
     main.cpp: In function `int main()':
     main.cpp:8:27: note: synthesized method `ObjectHolder::ObjectHolder(const ObjectHolder&)' first required here

Answer 1

编译器无法在 ObjectHolder 中生成(合成)复制构造函数，因为它包含类 NonCopyableObject 的对象，该对象具有私有(private)复制构造函数。

默认情况下，生成的复制构造函数调用所有成员对象和父对象的复制构造函数。