XABKEY

   You must provide a key definition XAB (XABKEY) for each key in an
   indexed file in order to define the key's characteristics. Before
   you create an indexed file, you must establish the contents of
   the XABKEY fields for the primary key and for each alternate key.

   When you invoke an Open or Display service for an existing
   indexed file, you can use XABKEYs if you want to provide your
   program with one or more of the key definitions specified when
   the file was created. Alternatively, the summary XAB provides
   the number of keys, the number of allocated areas, and the prolog
   version assigned to the file.

   The following table lists the symbolic offset, the size in bytes,
   FDL equivalent, and a brief description of each field.

   Offset        Size    FDL Equivalent    Description

   XAB$B_BLN     1       None              Block length
   XAB$B_COD     1       None              Type code
   XAB$L_COLNAM  4       None              Collating sequence name
   XAB$L_COLSIZ  4       None              Collating sequence table
                                           size
   XAB$L_COLTBL  4       COLLATING_        Collating sequence table
                         SEQUENCE          address
   XAB$B_DAN     1       KEY DATA_AREA     Data bucket area number
   XAB$B_DBS     1       None              Data bucket size
   XAB$W_DFL     2       KEY DATA_FILL     Data bucket fill size
   XAB$B_DTP     1       KEY TYPE          Data type of the key
   XAB$L_DVB     4       None              First data bucket virtual
                                           block number
   XAB$B_FLG     1       KEY               Key options flag
   XAB$B_IAN     1       KEY INDEX_AREA    Index bucket area number
   XAB$B_IBS     1       None              Index bucket size
   XAB$W_IFL     2       KEY INDEX_FILL    Index bucket file size
   XAB$L_KNM     4       KEY NAME          Key name buffer address
   XAB$B_LAN     1       KEY LEVEL1_       Lowest level of index
                         INDEX_AREA        area number
   XAB$B_LVL     1       None              Level of root bucket
   XAB$W_MRL     2       None              Minimum record length
   XAB$B_NSG     1       None              Number of key segments
   XAB$B_NUL     1       KEY NULL_VALUE    Null key value
   XAB$L_NXT     4       None              Next XAB address
   XAB$W_POSn    2       KEY POSITION and  Key position, XAB$W_POS0
                         SEGn_POSITION     to XAB$W_POS7
   XAB$B_PROLOG  1       KEY PROLOG        Prolog level
   XAB$B_REF     1       KEY n             Key of reference
   XAB$L_RVB     4       None              Root bucket virtual block
                                           number
   XAB$B_SIZn    1       KEY LENGTH and    Key size XAB$B_SIZ0 to
                         SEGn_LENGTH       XAB$B_SIZ7
   XAB$B_TKS     1       None              Total key field size