Specialize member function for stl container

Question

I have a class like this:

class Foo
{

    ...
    template<template<typename...> class container>
    void fillContainer(container<int> &out)
    {
        //add some numbers to the container
    }
    ...

}

I did it this way to be able to handle different stl Containers. Now I want to create a specialization for std::vector to reserve the Memory (I know the amount of numbers to insert). I read this and this post, so I did the following:

class Foo
{
    //Same Thing as above
}

template<>
void Foo::fillContainer(std::vector<int> &out)
{
    //add some numbers to the container
}

Now I get the error: error: no member function 'fillContainer' declared in 'Foo' . I guess the Problem is template<template<typename...> class container> .

Is there a possibility to specialize this function for std::vector ?

Answer 1

There is no reason to try and specialize it, just add an overload:

class Foo
{
    ...
    template<template<typename...> class container>
    void fillContainer(container<int>& out)
    {
        //add some numbers to the container
    }

    void fillContainer(std::vector<int>& out)
    {
        //add some numbers to the container
    }

    ...
};

(There are a few, obscure cases where it makes a difference, such as if someone wants to take the address of the function template version, but nothing that requires it to be specialized rather than the much simpler approach of overloading.)