Effective C++ 笔记 —— Item 6: Explicitly disallow the use of compiler-generated functions you do not want.

To disallow functionality automatically provided by compilers:

1. declare the corresponding member functions private and give no implementations.

class HomeForSale 
{
public:
    //...
private:
    //...
    HomeForSale(const HomeForSale&);        // declarations only
    HomeForSale& operator=(const HomeForSale&);
};

2. Using a base class like Uncopyable is one way to do this

class Uncopyable 
{
protected:                // allow construction
    Uncopyable() {}        // and destruction of
    ~Uncopyable() {}    // derived objects...
private:
    Uncopyable(const Uncopyable&);        // ...but prevent copying
    Uncopyable& operator=(const Uncopyable&);
};

/*To keep HomeForSale objects from being copied, all we have to do now is inherit from Uncopyable :*/
class HomeForSale : private Uncopyable 
{ 
    // class no longer declares copy ctor or copy assign. operator
};