namespace std {
template<class T> struct is_bind_expression; // see below
}
The class template is_bind_expression can be used to detect function objects generated by bind. The function template bind uses is_bind_expression to detect subexpressions.
Instantiations of the is_bind_expression template shall meet the UnaryTypeTrait requirements. The implementation shall provide a definition that has a base characteristic of true_type if T is a type returned from bind, otherwise it shall have a base characteristic of false_type. A program may specialize this template for a user-defined type T to have a base characteristic of true_type to indicate that T should be treated as a subexpression in a bind call.