You can use the CVAFFILT macro to invoke the CVAF filter service. You can also use it to map or initialize the CVAF parameter list (CVPL). CVAF filter retrieves data set DSCB chains from an indexed or nonindexed VTOC and places them in buffers you provide. You can request the DSCBs for a single partially-qualified data set name or for a list of fully-qualified data set names.

Identify a specific DASD device and provide both a filter criteria list (FCL) defining the request, and a CVAF buffer list (with buffers) for DSCB return. The format of the two elements of the FCL is shown in Table 1 and Table 2. The format of the buffer list is shown in Using Buffer Lists. CVAFFILT returns a complete set of DSCBs in the order that they are chained in the VTOC (format-1, format-2, then format-3).

Keywords coded on the list form of the macro need not be coded on the execute form. Keywords coded on one CVAFFILT call remain in effect for subsequent calls unless overridden, if you use the same CVAFFILT parameter list.

See Reading Sets of DSCBs with CVAF Filter for additional information.

The format of the CVAFFILT macro is:

>>-+-------+--CVAFFILT--+---------------------+----------------->
   '-label-'            |          .-READ---. |   
                        '-,ACCESS=-+-RESUME-+-'   
                                   '-RLSE---'     

>--+---------------------+--+-----------------+----------------->
   '-,BUFLIST=-+-addr--+-'  +-,UCB=-(ucbaddr)-+   
               '-(reg)-'    '-,DEB=addr-------'   

>--+-----------------+------------------------------------------>
   '-,FCL=-+-addr--+-'   
           '-(reg)-'     

>--+------------------------------------+----------------------->
   |           .-NOKEEP---------------. |   
   '-,FLTAREA=-+-KEEP-----------------+-'   
               +-(KEEP,-+-addr--+-)---+     
               |        '-(reg)-'     |     
               '-(NOKEEP,-+-addr--+-)-'     
                          '-(reg)-'         

>--+-----------------------------------+------------------------>
   |          .-NOKEEP---------------. |   
   '-,IOAREA=-+-KEEP-----------------+-'   
              +-(KEEP,-+-addr--+-)---+     
              |        '-(reg)-'     |     
              '-(NOKEEP,-+-addr--+-)-'     
                         '-(reg)-'         

>--+------------------------------+--+--------------------+----->
   |          .-NO--------------. |  |          .-NOTOK-. |   
   '-,BRANCH=-+-YES-------------+-'  '-,EADSCB=-+-OK----+-'   
              '-(YES,-+-SUP-+-)-'                             
                      '-PGM-'                                 

>--+--------------------------+--------------------------------><
   |      .-I---------------. |   
   '-,MF=-+-D---------------+-'   
          +-L---------------+     
          '-(E,-+-addr--+-)-'     
                '-(reg)-'