Specifies that the type can be used as the template argument of std::valarray.
for a type T to be an NumericType:
T cannot be a reference T cannot be cv-qualified T is a class, it operator& T::T(const T&) T& T::operator=(const T&) or T& T::operator=(T) T() has the same effect as value-initialization T may throw exceptions
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/named_req/NumericType