为什么包含此标头会导致此错误？

Question

This is a header and source for a class I have. There are similar other classes, all of which have to be included in one central class.

However, including the file GameObject.h in the header below causes an error:

error C2582: 'operator =' function is unavailable in 'Node'

Although this error seems a little obscure, I have a slightly older working version of the code, and the only difference is that Node now inherits from GameObject.

Header:

#ifndef NODE_H
#define NODE_H

#include <d3d10.h>
#include <d3dx10.h>
#include "GameObject.h"

class Mesh;

class Node : public GameObject
{
public: 
Node(Mesh& mesh);
};

#endif

source:

#include "Node.h"
#include "Mesh.h"

Node::Node(Mesh& mesh) : GameObject(mesh)
{

}

In the call stack I am eventually pointed to a declaration of a vector of node objects as the cause, but I have no idea why this is happening as there are other objects that also inherit from gameObject that are also in vectors.

std::vector<Node> nodes;

Answer 1

However, including the file GameObject.h in the header below causes an error:

This implies that the only difference between the working and non-working code is the inclusion of that header file, but ,

I have a slightly older working version of the code, and the only difference is that Node now inherits from GameObject.

This implies that there is another difference: Node now inherits from GameObject . Which is the the inclusion of the inheritance that is causing the problem?

Assuming that it is the inheritance that is causing the problem, I guess you have a private or otherwise unavailable operator= in GameObject . Since vector s like to copy objects around, you'll be needing an operator= available in both GameObject and Node .

In the alternative, you may have a reference inside GameObject that is preventing the compiler from providing its automatic assignment operator, thus preventing Node from having an automatic assignment operator.

In sum: If, inside GameObject , you have either a private operator= or a non-static reference (like Mesh& ), then you will need to create an Node::operator= for vector to use.

References :

• http://msdn.microsoft.com/en-us/library/aa983787(v=vs.71).aspx