我有一个用例,即我的对象不得以任何方式复制。我在下面写了一份夸张的复制构造函数和复制赋值运算符删除的完整列表。它们太多了,我无法确定该使用哪些,有时这让我变得偏执。我不必将它们全部写在我的代码中,不是吗?那么,为了防止任何类型的对象复制,我应该使用其中哪一个?
MyClass ( MyClass &) = delete;
MyClass (const MyClass &) = delete;
MyClass ( MyClass &&) = delete;
MyClass (const MyClass &&) = delete;
MyClass operator=( MyClass &) = delete;
MyClass operator=(const MyClass &) = delete;
const MyClass operator=( MyClass &) = delete;
const MyClass operator=(const MyClass &) = delete;
MyClass & operator=( MyClass &) = delete;
MyClass & operator=(const MyClass &) = delete;
const MyClass & operator=( MyClass &) = delete;
const MyClass & operator=(const MyClass &) = delete;
MyClass && operator=( MyClass &) = delete;
MyClass && operator=(const MyClass &) = delete;
const MyClass && operator=( MyClass &) = delete;
const MyClass && operator=(const MyClass &) = delete;
MyClass operator=( MyClass &&) = delete;
MyClass operator=(const MyClass &&) = delete;
const MyClass operator=( MyClass &&) = delete;
const MyClass operator=(const MyClass &&) = delete;
MyClass & operator=( MyClass &&) = delete;
MyClass & operator=(const MyClass &&) = delete;
const MyClass & operator=( MyClass &&) = delete;
const MyClass & operator=(const MyClass &&) = delete;
MyClass && operator=( MyClass &&) = delete;
MyClass && operator=(const MyClass &&) = delete;
const MyClass && operator=( MyClass &&) = delete;
const MyClass && operator=(const MyClass &&) = delete;
您只需将单个复制构造函数和复制赋值运算符标记为
delete
。复制版本的存在将阻止移动构造函数和移动赋值运算符的隐式声明,并且声明一种形式的复制特殊成员函数会抑制其他形式的隐式声明。
MyClass (const MyClass&) = delete;
MyClass& operator= (const MyClass&) = delete;
请注意,C++11 后,默认的赋值运算符隐式定义已被弃用,而应将其定义为已删除。