C++ gcc和Visual Studio的不同编译错误，'within this context'

C++ Different compilation error with gcc and visual studio, 'within this context'

本文关键字：within context this 错误 编译 Visual gcc Studio C++      更新时间：2023-10-16

我以前贴过一个类似的问题，但我在代码中有一个小错误，所以它被忽略了，让我再问一次。

在Gcc中，我得到了编译错误的确切行在VS2010/2012我不知道编译错误在哪里，有人能帮助吗?**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:usersuserdocumentsvisual studio 2012projectstestertesterobjectholder.h(13): 
     error C2248: 'NonCopyableObject::NonCopyableObject' : cannot access private member declared in   class 'NonCopyableObject'
               d:usersuserdocumentsvisual studio 2012projectstestertester  
     noncopyableobject.h(13) : see declaration of 'NonCopyableObject::NonCopyableObject'
            d:usersuserdocumentsvisual studio 2012projectstestertester
     noncopyableobject.h(6) : see declaration of 'NonCopyableObject'
            This diagnostic occurred in the compiler generated function    
     'ObjectHolder::ObjectHolder(const ObjectHolder &)'

GCC: 

$ 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

编译器不能在ObjectHolder中生成(合成)复制构造函数，因为它包含一个具有私有复制构造函数的NonCopyableObject类的对象。

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。

使用不同的编译器进行编译是一个好主意，因为不同的编译器之间的错误差异很大，其中一个可能比另一个更有帮助。在大多数情况下，我发现Clang的错误报告是最好的。在您的示例中:

source.cpp:9:48: error: unused parameter 'other' [-Werror,-Wunused-parameter]
    NonCopyableObject(const NonCopyableObject& other) {}
                                               ^
source.cpp:25:18: error: call to implicitly-deleted copy constructor of 'ObjectHolder'
    ObjectHolder second(first);
                 ^      ~~~~~
source.cpp:18:23: note: copy constructor of 'ObjectHolder' is implicitly deleted because field 'obj' has an inaccessible copy constructor
    NonCopyableObject obj;

您正在尝试复制ObjectHoder 

ObjectHolder second(first);

但是它包含一个不可复制的对象，所以它不能被复制。您正在尝试执行代码在编译时被设计为不允许的操作。两个编译器都告诉你这个

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