Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

System Functions (n - p) put_regOSSFileIOHandler(2)
PUT_ERROR The specified filedes was less than 0 (zero).
PUT_ERROR filedes was already registered prior to this call.
PUT_ERROR functionPtr is NULL.
527186-023 Hewlett-Packard Company 5−257