CA Compress/2 › Calling the Subroutines › Assembler Language › CALL to Subroutine CLOSE

CALL to Subroutine CLOSE

Each call to the CLOSE subroutine frees all main storage obtained to support one FDT-compressed data set. Application programs normally call CLOSE only if all processing is complete for the compressed file in question, or if the storage needs to be released for other processing.

CA Compress/2 obtains main storage for each data set compressed using an FDT for the FDT, the compression and expansion tables, and the custom-compiled code. The amount of storage obtained for a particular file varies, depending upon the extent and complexity of record definitions. It can vary from about 2K to as much as 24K per file, though approximately 6K is usual.

Once CLOSE is called for a file, the FDT, compression and expansion tables and custom-compiled code to perform subroutine functions for the file are no longer available. Any subsequent call referencing that data set causes the FDT and compression and expansion tables to be brought into storage again, and custom code to be recompiled. CLOSE requires one parameter—the File Descriptor Table Identifier. If the FDT is in sequential data set format, this is the address of a binary fullword containing the file number. If the FDT is in load module format, the File Descriptor Table Identifier is the address of the SCB associated with this data set. See Accessing the FDT in this chapter for more information.

The following are model statements for calling CLOSE:

Assembler Language

CALL CLOSE,(FDT),VL

COBOL

CALL 'CLOSE' USING FDT.

PL/I Optimizer

CALL CLOSE(FDT);