To read or write one or more DSCBs by specifying only the data set name (that is, BFLEARG is zero), specify either ACCESS=READ or ACCESS=WRITE.

Specify the address of the data set name in the DSN keyword. Specify the address of the buffer list in the BUFLIST keyword. Each of these areas and the associated buffers must be in your program's protect key.

The buffer list must contain at least one buffer list entry with the skip bit off and a pointer to a 96-byte first buffer. Do not use a 140-byte buffer as the first buffer. You can chain buffer list headers together, but at this time, CVAF only uses the first buffer list.

For an indexed VTOC, CVAF searches the index for the data set name. If the data set name is found, the DSCB argument is put into the buffer list entry and used to read or write the DSCB. If the data set name cannot be found in the index, CVAF performs a key search of the VTOC.

For a nonindexed VTOC, CVAF uses a channel program to perform a key search of the VTOC to locate the data set name and read or write the DSCBs. If the data set name is found, CVAF puts the DSCB argument into the buffer list entry.

The DSCB argument returned in the buffer list entry is in the format determined by the BFLECHR or BFLETTR bits in the buffer list entry.

If CVAF does not find the data set name in the VTOC, a return code of 4 is indicated in register 15, and an error code of 1 in the CVSTAT field.

For CVAF calls that pass a data set name, a CVAFDIR request will fail if the EADSCB=OK indicator is not set and the DSCB associated with this data set name is a format-8 DSCB. CVAF return code of 4 with a CVAF status code (CVSTAT) of STAT082 will be set.

If you use CVAFDIR MULTIPLEDSCBS=YES ACCESS=READ, all DSCBs associated with this data set name are read and returned in the buffer list buffer (BFLEBUF) for entries without the skip bit on in logical VTOC order. The associated address of each DSCB is put in the corresponding BFLEARG field. The total number of DSCBs associated with this data set name is also returned in the BFLHNOEN field of the buffer list header. If there are not enough buffers to house all the DSCBs associated with this data set name, only those DSCBs that have BFLEs are processed. The buffer list header field BFLHNOEN will then have a number greater than the BFLHNOE field.

If you use CVAFDIR MULTIPLEDSCBS=YES ACCESS=WRITE, all BFLEs without the skip bit are used to write all DSCBs with one call. BFLARG must be correct for all entries (except the first 96-byte DSCB) and BFLEBUF must point to the correct corresponding DSCB to be written.