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一、介绍

在C ++ 11之前，操作符delete 只有一个目的，即释放已动态分配的内存。而C ++ 11标准引入了此操作符的另一种用法，即：禁用成员函数的使用。这是通过附加= delete来完成的; 说明符到该函数声明的结尾。

使用’= delete’说明符禁用其使用的任何成员函数称为expicitly deleted函数。

虽然不限于它们，但这通常是针对隐式函数

二、实例

禁用拷贝构造函数：

// copy-constructor using delete operator #include 
   
     using namespace std;   class A { public:     A(int x): m(x) { }           // Delete the copy constructor     A(const A&) = delete;          // Delete the copy assignment operator     A& operator=(const A&) = delete;      int m; };   int main() {     A a1(1), a2(2), a3(3);     // Error, the usage of the copy assignment operator is disabled     a1 = a2;       // Error, the usage of the copy constructor is disabled     a3 = A(a2);      return 0; }
   

禁用不需要的参数转换

// type conversion using delete operator #include 
   
     using namespace std; class A { public:     A(int) {}     // Declare the conversion constructor as a  deleted function. Without this step,      // even though A(double) isn't defined,  the A(int) would accept any double value    //  for it's argumentand convert it to an int     A(double) = delete;  }; int main() {     A A1(1);     // Error, conversion from  double to class A is disabled.     A A2(100.1);      return 0; }
   

 禁止拷贝的基类

//禁止拷贝基类class noncopyable {protected:    noncopyable() {}    ~noncopyable() {}private:    //禁止拷贝    noncopyable(const noncopyable &that) = delete;    noncopyable(noncopyable &&that) = delete;    noncopyable &operator=(const noncopyable &that) = delete;    noncopyable &operator=(noncopyable &&that) = delete;};

最后，明确删除函数有什么好处？

参考：

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