User Exits › Transparency User Exit › Enabling the User Exit

Enabling the User Exit

The user exit is enabled by the UEXIT parameter of the Control File Maintenance Utility ADD and ALTER statements. UEXIT is coded just like the EXCLUDE parameter, whose syntax is found in the descriptions of the ADD and ALTER statements in the chapter Control File Maintenance.

If UEXIT is not specified, or if the exit is unavailable when CA Compress tries to load it, compression and expansion are performed without it. If the exit is specified but is unavailable, CA Compress issues message ZSUR296I, described below.

The expansion phases can only receive control if the preceding GET was successful, because CA Compress attempts expansion only when the record has been successfully read. Because compression is performed before writing the record, the PUT has not yet been done when the compression phases receive control, so errors in the exit may cause I/O errors when CA Compress tries to write the record.