22.7 Exception Delivery in the Callback Model

   The ReplyHandler interface is expressed in IDL and thus cannot have operations that take exceptions as arguments. Furthermore, the most natural way for a ReplyHandler to deal with exceptions is by invoking some operation that raises exceptions, not through inspecting operation parameters. Therefore, exception replies are propagated to the ReplyHandler in the form of a type-specific Messaging::ExceptionHolder valuetype instance that contains the marshaled exception as its state and has raise_exception and raise_exception_with_list operations for raising the encapsulated exception.