Variadic templates with exactly n parameters

Question

I want to make a variadic template with exactly N arguments, where N is also a template parameter. For example,

template 
void fu         


        

Answer 1

You can use std::enable_if instead of static_assert:

template <std::size_t N, typename ...Args>
auto function(Args&&... args)
    -> typename std::enable_if<N == sizeof...(Args), void>::type
{
    ...
}

Update: It's also possible to use it in constructors, where N is a template argument of the class.

template <std::size_t N>
struct foobar
{
    template <typename ...Args, typename = typename std::enable_if<N == sizeof...(Args), void>::type>
    foobar(Args&&... args) { ... }
};