For constructors, how do I choose between variadic-templates vs std::initializer_list?

Question

In the current state of c++11 (say gcc 4.7.2), how should I choose between using a variadic-template or a std::initializer_list when I need a constructor t

Answer 1

With a variadic template, the number of arguments is known during compilation (and accessible via sizeof...). With a std::initializer_list, the number of arguments is known only at runtime. So part of the decision depends on when you need or want to know how many arguments you have.