The Cascade DataHub, by default, creates any points that do not currently exist whenever it receives a read, write or exception request message. This allows the DataHub to populate itself without having any a-priori information about the system in which it is running. On occasion, it may be useful for a task to determine whether a point exists. This may be done using the functions DH_WriteExistingPoint, DH_ReadExistingPoint and DH_RegisterExistingPoint. These functions will return an error if the named point does not exist when the function is called.