Coding the DSECT macro for interleaved files

The following statements are needed in the DSECT of any program that accesses data in any of the three interleaves:

&SW00ILV SETC '3'         Number of interleaves
&SW00BOR SETC '0'         Starting ordinal
&SW00EOR SETC '25'        Ending ordinal
&SW00RBV SETC '#TPFDB01'  Addressing algorithm
&SW00EO# SETC '-1'        FACE end ordinal

&SW00ILV defines a set of three interleaved files. Code the remaining &SW00xxx fields, including &SW00RBV as if the file were non-interleaved. &SW00EO# is coded as '-1', but can also be coded as '77'.

The application program can specify the interleave by coding the INTERLV parameter in a DBOPN macro. For example:

DBOPN REF=zzzzzz,...,INTERLV=label

In this example, store the interleave number in location label before coding the DBOPN macro statement.

Alternatively, the program can specify the interleave by using the INTERLV parameter when it calls other macros (for example, DBRED or DBADD). This is less controlled, and is not recommended.

For C applications, a program accesses an interleave using the dfopt function with the DFOPT_INTERLEAVE option.