DBCAIRX is used when initiating requests. It is of variable length, is not initialized by DBCHINI, and is allocated by the application. It is ignored by other DBCHCL functions.
When the DBCAREA Extension-pointer field is not zero, it points to one or more DBCAIRX and DBCACNX extensions; when zero, no DBCAIRX or DBCACNX extensions exist for the request.
The prologue for the Assembler, COBOL, C, and PL/I mappings of the DBCAIRX provides language-dependent information in constructing an extension and should be consulted.
The application should set unused fields to binary zeroes. This will allow successful execution of existing applications should these fields ever be used.