Detailed Description

Some templates cannot use void as a parameter: void is not a complete type, and it cannot be a function argument or a member. Void is an empty complete type that fills that slot. A traits specialization, a signal with no value, or a tuple-like parameter pack can name Void to mean "this parameter is absent" without leaving the type system.

Void has no data and no operations of its own. Compare it with typeid or a template specialization, do not construct values of it as application data.