undefined reference to, but it is defined

Question

I have a class A with virtual inline getters and setters. From A there are two classes B and C derived. And I have a class D, derived from B and C. Creatung an object from D and using the getName() results in "undefined reference to getName()". Removing "inline" doens't work. The header file is included correctly. What's the problem here?

class A
{
    public:
        virtual inline std::string getName() const{return name;}

    protected:
        std::string name;
};

class B : public virtual A {};
class C : public virtual A {};

class D : public B, public C {};

Paste code that demonstrates the problem. The code above does not show it. — wilx, Mar 19 '11 at 09:02
possible duplicate of [gcc c++ virtual inheritance problem](http://stackoverflow.com/questions/2126522/gcc-c-virtual-inheritance-problem) — Prasoon Saurav, Mar 19 '11 at 09:07

score 2 · Accepted Answer · edited May 23 '17 at 12:04

2

Your code compiles fine with/without inline : with inline and without inline

But remember this otherwise : in a virtual inheritance, you've to initialize the base explicitly IF the base class constructor takes parameter as,

class D : public B, public C 
{
   public:
      D(string s) : A(s), B(s), C(s){}
                  //^^^^ note this!

};

Just D(string s) : B(s), C(s) would not be enough: http://ideone.com/MPUPj

A(s) is also needed : http://ideone.com/DNLkA

See this topic for more detail: about virtual base class and virtual inheritance in C++

edited May 23 '17 at 12:04

Community

1
1

answered Mar 19 '11 at 09:04

Nawaz

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No, you don't have to explicitly initialize the virtual base if it is default-constructible, which in this case it is. No? – Armen Tsirunyan Mar 19 '11 at 09:15
Wouldn't the compiler generate a working default constructor since there is no constructor defined in the code from the question? – rve Mar 19 '11 at 09:18
@Armen: You're right. I missed that point. Updated my answer! – Nawaz Mar 19 '11 at 09:20

undefined reference to, but it is defined

1 Answers1