I want to inherit from a class with a template contructor but it seems i cannot call this contructor the way i want.

The error is not finding a matching Base::Base()

I tried to call the contructor with Base<T>() but it doesn’t work. it gets me ‘class Base Base::Base’ is not a non-static data member of ‘Derived’ error.

I thought about using Base::Base or using Base::Base<T> but it doesn’t help. and my Base class is not a class template so i shouldn’t inherit this way : class Derived : public Base<T>

Why do i use templates, you may ask ? I want to instantiate my Derived class this way : ‘Derived’ so i don’t havec to declare it this way :

Derived d;
d.setFoo(new Foo);

main.cpp

#include "Foo.hpp"


int main(void)
{
    Derived<Foo> derived;

    return 0;
}

Base.hpp

#include "Foo.hpp"

class Foo;

class Base
{
private:
Foo* m_p_foo;

public:
    template <typename T>
    Base()
    {
        m_p_foo = new T(this);
    }

    ~Base();
};

template <typename T>
class Derived : public Base
{
public:
    Derived():Base(){};
};

Base.cpp

#include "Base.hpp"

Base::~Base()
{
    delete m_p_foo;
};

Foo.hpp

#pragma once
#include "Base.hpp"

class Base;

class Foo
{
Base* m_p_base;

public :
    Foo(Base* p_base){m_p_base = p_base;};
    ~Foo();
};

Foo.cpp

#include "Foo.hpp"

Foo::~Foo()
{
    delete m_p_base;
};

Errors :

In file included from src/Foo.hpp:2,
                 from src/main.cpp:1:
src/Base.hpp: In instantiation of 'Derived<T>::Derived() [with T = Foo]':
src/main.cpp:6:18:   required from here
src/Base.hpp:25:20: error: no matching function for call to 'Base::Base()'
   25 |     Derived():Base(){};
      |                    ^
src/Base.hpp:13:5: note: candidate: 'template<class T> Base::Base()'
   13 |     Base()
      |     ^~~~
src/Base.hpp:13:5: note:   template argument deduction/substitution failed:
src/Base.hpp:25:20: note:   couldn't deduce template parameter 'T'
   25 |     Derived():Base(){};
      |                    ^
src/Base.hpp:6:7: note: candidate: 'constexpr Base::Base(const Base&)'
    6 | class Base
      |       ^~~~
src/Base.hpp:6:7: note:   candidate expects 1 argument, 0 provided