Virtual function replaced by a non-virtual one

Asked Jun 21 '18 at 11:32

Active Jun 21 '18 at 11:32

Viewed 41 times

Today I have found something which really surprised me:

#include <iostream>

using namespace std;

class A {
public:
    virtual void reset() = 0;
};

class B : public A {
public:
    virtual void reset() override {
        cout << "reset()";
    }
};

class C : public B {
public:
    void reset(int r) {
        cout << "reset(" << r << ")";
    }
};

int main()
{
    C c;
    c.reset();
    return 0;
}

If I try to compile the code as is, the compiler complains about reset() not matched. However if I comment reset(int r) out, reset() is miraculously found. How is this possible? There isn't a signature conflict or whatever so why is this happening?

asked Jun 21 '18 at 11:32

Miro Kropacek

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3

When I turn on warnings, the compiler tells me that `C::reset` hides `B::reset` because it has a different signature. You should turn on warnings. – Eljay Jun 21 '18 at 11:34
2

This is called "name hiding" and there are loads of explanations on StackOverflow and elsewhere. – Jonathan Wakely Jun 21 '18 at 11:35
@Eljay at least my g++ 8.1 -Wall -std=gnu++11 doesn't emit any warnings. – Miro Kropacek Jun 21 '18 at 11:44
Ironically, GCC `-Wall` does not include all the warnings. Add `-Woverloaded-virtual`. – Eljay Jun 21 '18 at 11:50

Virtual function replaced by a non-virtual one

0 Answers0