在C中,减少派生类中返回类型的cv限定符是有效的：
class Base {
virtual const Base* f();
};
class Derived : public Base {
Base* f() override;
};
这对指向原始类型的指针有效吗？
class Base {
virtual const int* f();
};
class Derived : public Base {
int* f() override;
};
解决方法
协变cv限定符是否适用于C中的原始类型？
没有
§ 10.3.7 Virtual functions
The return type of an overriding function shall be either identical to the return type of the overridden function or covariant with the classes of the functions. If a function
D::foverrides a functionB::f,the return types of the functions are covariant if they satisfy the following criteria:
- both are pointers to classes,both are lvalue references to
classes,or both are rvalue references to classes- the class in the return type of
B::fis the same class as the class
in the return type ofD::f,or is an unambiguous and accessible
direct or indirect base class of the class in the return type ofD::f- both pointers or references have the same cv-qualification and the
class type in the return type ofD::f
