[C++] C++11 template Parameter Packs

A function parameter pack declaration is a function parameter declaration containing
a template parameter pack expansion.

It must be the last parameter in the function
parameter list.

Class templates may have at most one parameter pack, which must be at the end of
the template parameter list;

but function templates, thanks to template argument type
deduction, may have multiple parameter packs, e.g. (from C++11),


template<class... TTypes, class... UTypes>
bool operator==(const tuple<TTypes...>& t, const tuple<UTypes...>& u);