Question

如果某个类型的默认成员被删除，那么该声明的可访问性是否有所不同？

class FooA {
public:
  FooA() = delete;
  FooA(FooA const&) = delete;
  FooA& operator=(FooA const&) = delete;
}

class FooB {
private:
  FooB() = delete;
  FooB(FooB const&) = delete;
  FooB& operator=(FooB const&) = delete;
}

class FooC {
protected:
  FooC() = delete;
  FooC(FooC const&) = delete;
  FooC& operator=(FooC const&) = delete;
}

Answer 1

虽然accessibility and deletedness are orthogonal，但很难看出你提议的案例会有什么实际差异。

Answer 2

可能是人为的，但确实有所不同

class FooA {
private:
  FooA& operator=(FooA const&) = delete;
};

class FooB : FooA {
  // ill-formed because FooB has no access
  using FooA::operator=;  
};

是否是实用的差异......我真的不知道。如果FooA是模板参数，并且您说using T::BazBang，则可能会在实践中发生。

被删除的构造函数/运算符的可访问性是否重要？

2 个答案: