boost::algorithm::operator! — predicate negation operator
template<typename PredT> unspecified operator!(const predicate_facade< PredT > & Pred);
Construct the class_not predicate. This predicate represents a negation. class_or holds if of the predicates return false.
class_not
class_or
Parameters
The predicate to be negated
Returns: An instance of the class_not predicate