Non-type variadic function templates in C++11

Question

I saw a blog post which used non-type variadic templates (currently not supported by gcc, only by clang).

template 
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Answer 1

You are simply confusing type names and non-type names. What you want simply doesn’t work.

You can probably use variadic non-type templates in functions, but not as (non-template) arguments:

template 
int max()
{
    int tmp = max();
    return N < tmp ? tmp : N;
}

std::cout << max<3, 1, 4, 2, 5, 0>() << std::endl;

… although I haven’t tested this and I’m not sure how this should work given that you need to have a partial specialisation as the base case. You could solve this by dispatching to a partially specialised struct:

template 
struct max_t {
    static int const value = max_t::value > N ? max_t::value : N;
};

template 
struct max_t {
    static int const value = N;
};


template 
int max()
{
    return max_t::value;
}

This will work.