Use brace-enclosed initializer lists in a variadic template?

Question

I\'m trying to use brace-enclosed initializer lists in a variadic template function, but the compiler complains... am I asking too much or did I do something wrong?

Answer 1

This is a rough attempt at what you want...

#include <iostream>
#include <initializer_list>

struct Bracy {
    Bracy(int x, int y) {}
};

struct Test {
    void consumeOne(std::initializer_list<int>) { std::cout << "initializer list version (Bracy?)\n"; /* Bracy? */}

    void consumeOne(int) { std::cout << "int version\n"; }

    template<typename T>
    void consume(T t) { consumeOne(t); }

    template<typename T, typename ... Args>
    void consume(T first, Args ... args) {
        consumeOne(first);
        consume(args...);
    }

    template<typename ... Args>
    Test(Args ... args) {
        consume(args...);
    }
};

int
main(int argc, char** argv) {
    Test(1, std::initializer_list<int>{1,2}, 2, 3, std::initializer_list<int>{1,2});
    return 0;
}

output: int version
        initializer list version (Bracy?)
        int version
        int version
        initializer list version (Bracy?)

Answer 2

A brace enclosed initializer list cannot be forwarded, so you are unfortunately out of luck.