具有相同纯虚函数的两个基类

Question

我有一个class A继承自class B。所以class A的接口包含class B的一些纯虚函数和一些函数class A 的。现在我需要为 class A 进行单元测试，所以想要为 class A 提供一些我可以模拟的接口。所以现在我想知道给定的代码在 C++14 中是否正确，它是否会导致 UB:

class Base1 {
public:
  virtual void func() = 0;
};

class Base2 {
public:
  virtual void func() = 0;
};

class Derived : public Base1, public Base2 {
public:
  void func() override { }
};

int main() {
  Derived d;
  d.func();
  return 0;
}

Answer 1

是的，此代码是 well-formed，void func() 覆盖了 A::func() 和 B::func()。来自 C++14 标准：

[class.virtual]

If a virtual member function vf is declared in a class Base and in a class Derived, derived directly or indirectly from Base, a member function vf with the same name, parameter-type-list (8.3.5), cv-qualification, and ref-qualifier (or absence of same) as Base::vf is declared, then Derived::vf is also virtual (whether or not it is so declared) and it overrides Base::vf.

具有相同纯虚函数的两个基类

Two base classes with the same pure virtual function

c++

inheritance

virtual-functions