Determining if Ddname or Dsname is Allocated (Entry Code X’00’)
Build the DAIR parameter block shown in Table 1 to request that DAIR determine whether the specified dsname or ddname is allocated. Use the IKJDAP00 mapping macro, which is provided in SYS1.MACLIB, to map this DAIR parameter block.
| Number of bytes | Field name | Contents or meaning |
|---|---|---|
| 2 | DA00CD | Entry code X'0000' |
| 2 | DA00FLG | A flag field set by DAIR before returning to the
calling routine. The flags have the following meaning: Byte 1:
Byte 2:
|
| 4 | DA00PDSN | Place in this field the address of the dsname
buffer. The dsname buffer is a 46-byte field with the following format: The first two bytes contain the length, in bytes of the dsname; the next 44 bytes contain the dsname, left justified, and padded to the right with blanks. |
| 8 | DA00DDN | Contains the ddname for the requested data set. If a dsname is present, the DAIR service routine ignores the contents of this field. |
| 1 | DA00CTL | A flag field:
|
| 2 | Reserved. Set these bytes to zero. | |
| 1 | DA00DSO | A flag field. These flags describe the organization
of the data. They are returned to the calling routine by the DAIR
service routine.
|
After DAIR searches the data set entry for the fully-qualified data set name, register 15 contains one of the following DAIR return codes: 0, 4, or 52. See Return Codes from DAIR for return code meanings.