Returns information related to the primary and secondary device
    characteristics of an I/O device.

                                   NOTE

       All pathname-related information pertains only to Alpha and
       Integrity server systems.

    For synchronous completion, use the Get Device/Volume Information
    and Wait ($GETDVIW) service. The $GETDVIW service is identical to
    the $GETDVI service in every way except that $GETDVIW returns to
    the caller with the requested information.

    For additional information about system service completion, see
    the Synchronize ($SYNCH) service.

                          NOTE ABOUT ITEM CODES

       For item codes that return a string data type, failure to
       pass in a buffer that is large enough to hold the returned
       data results in silent data truncation. When $GETDVI
       completes, VSI recommends that you check the returned length
       field of an item list descriptor for each item code that
       can return a string. If the returned length is equal to the
       size of the buffer allocated to hold the returned data, the
       data might have been truncated. In that case, call $GETDVI
       iteratively with a larger buffer until the length of the
       returned data is less than the size of the buffer allocated.

       Unless the description of an item code specifies otherwise,
       VSI recommends that you use a buffer of 32 bytes to hold
       the returned string. $GETDVI pads the unused portion of the
       buffer with null characters.

    Format

      SYS$GETDVI  [efn] ,[chan] ,[devnam] ,itmlst [,iosb] [,astadr]

                  [,astprm] [,nullarg] [,pathname]

    C Prototype

      int sys$getdvi  (unsigned int efn, unsigned short int chan,

                      void *devnam, void *itmlst, struct _iosb *iosb,

                      void (*astadr)(__unknown_params), int astprm,

                      struct _generic_64 *nullarg,...);