Variadic template call in subclass

Question

I'm struggeling with variadic templates in C++: I want to call a variadic template function implemented in class A from class B which inherits from A:

a.hpp

class A{
protected:
    template<typename... Ts>
    void variadic(Ts... args); 
};

a.cpp

#include "a.hpp"
template<typename... Ts>
void A::variadic(Ts... args) {/*something*/}

b.hpp

#include "a.hpp"
class B : public A {
public:
     void func() {
         variadic(4, 3.4, "hello");
     }
};

When I call the method (e.g. B testobj;testobj.func();) I always get the following linker error:

$ clang++ -std=c++11 main.cpp a.cpp -o main
/tmp/main-2e3fd9.o: In function `B::func()':
main.cpp:(.text._ZN1B4funcEv[_ZN1B4funcEv]+0x29): undefined reference to    `void A::variadic<int, double, char const*>(int, double, char const*)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

If I implement the variadic method directly in the header file I don't get any error. If I put func in class A it will also compile without error.

It seems to me that the variadic template isn't visible in class B. Is there any way to solve my issue?

Variadic template call in subclass

0 Answers0