The change use attribute installation exit (CBRUXCUA) is passed by way of register 1, the pointer to a parameter list mapped by CBRUXCPL. Here is the format of CBRUXCPL.
UXCPL DSECT , CBRUXCUA PARAMETER LIST
SPACE 1
********************************************************************
* *
* CHANGE USE ATTRIBUTE INSTALLATION EXIT PARAMETERS *
* *
********************************************************************
UXCPARM DS 0D CBRUXCUA PARAMETER SECTION
UXCLIB DS CL8 LIBRARY NAME
* (INPUT VARIABLE)
UXCLDEV DS CL8 LIBRARY DEVICE TYPE
* (INPUT VARIABLE)
UXCLCON DS CL8 LIBRARY CONSOLE NAME
* (INPUT VARIABLE)
UXCLTYP DS CL1 LIBRARY LOGICAL TYPE
* 'R' FOR AUTOMATED LIBRARY
* 'M' FOR MANUAL LIBRARY
* (INPUT VARIABLE)
UXCSUPPT DS XL1 SUPPORTED FUNCTION
UXCLOPM EQU X'80' ON IF OUTBOARD POLICY MANAGEMENT
* SUPPORTED IN LIBRARY
* (INPUT VARIABLE)
UXCJOBP EQU X'40' ON IF CALLING EXIT FOR JOB
* PROCESSING AND POLICY NAME
* CHANGES IGNORED
* (INPUT VARIABLE)
DS CL6 RESERVED
UXCLDESC DS CL120 LIBRARY DESCRIPTION
* (INPUT VARIABLE)
DS CL8 RESERVED
UXCVOLSR DS CL6 VOLUME SERIAL NUMBER
* (INPUT VARIABLE)
UXCVINFO DS XL1 ADDITIONAL VOLUME INFORMATION
UXCVLOPM EQU X'80' ON IF OUTBOARD POLICY INFORMATION
* RETRIEVED AS REQUESTED WITH
* GETPOLICY
* (INPUT VARIABLE)
UXCVCOPM EQU X'40' ON IF POLICY INFORMATION
* SPECIFIED ON CUA INTERFACE
* (INPUT VARIABLE)
UXCVWORM EQU X'20' ON IF VOLUME IS PHYSICAL WORM
* (INPUT VARIABLE – NOT TURNED ON
* FOR LOGICAL WORM)
UXCCUSEA DS CL1 CURRENT USE ATTRIBUTE OF THE VOLUME
* AS RECORDED IN THE TAPE
* VOLUME RECORD IN THE TCDB
* 'P' FOR PRIVATE
* 'S' FOR SCRATCH
* (INPUT VARIABLE)
UXCUSEA DS CL1 REQUESTED VOLUME USE ATTRIBUTE
* SPECIFIED ON THE CBRXLCS MACRO
* 'P' FOR PRIVATE
* 'S' FOR SCRATCH
* (INPUT VARIABLE)
UXCWPROT DS CL1 WRITE PROTECTION STATUS
* 'Y' FOR WRITE-PROTECTED
* 'N' FOR NOT WRITE-PROTECTED
* (INPUT FOR CHANGE TO SCRATCH
* OUTPUT FOR CHANGE TO PRIVATE)
UXCCHKPT DS CL1 CHECKPOINT VOLUME INDICATOR
* 'Y' FOR CHECKPOINT VOLUME
* 'N' FOR NOT CHECKPOINT VOLUME
* (INPUT FOR CHANGE TO SCRATCH
* OUTPUT FOR CHANGE TO PRIVATE)
UXCLOC DS CL1 VOLUME LOCATION CODE
* 'L' FOR LIBRARY-RESIDENT
* 'S' FOR SHELF-RESIDENT
* (INPUT/OUTPUT VARIABLE)
UXCTDSI DS 0F TAPE DEVICE SELECTION INFORMATION
UXCREC DS XL1 RECORDING TECHNOLOGY
* (INPUT VARIABLE)
UXCMEDIA DS XL1 MEDIA TYPE
* (INPUT VARIABLE)
UXCCOMP DS XL1 COMPACTION
* (INPUT VARIABLE)
UXCSPEC DS XL1 SPECIAL ATTRIBUTE
* (INPUT VARIABLE)
UXCGROUP DS CL8 STORAGE GROUP NAME
* (INPUT FOR CHANGE TO SCRATCH
* OUTPUT FOR CHANGE TO PRIVATE)
UXCSHLOC DS CL32 SHELF LOCATION
* (INPUT/OUTPUT VARIABLE)
UXCOWNER DS CL64 VOLUME OWNER INFORMATION
* (INPUT/OUTPUT VARIABLE)
DS CL8 RESERVED
UXCCREAT DS CL10 VOLUME RECORD CREATION DATE
* (INPUT VARIABLE)
UXCENTEJ DS CL10 LAST ENTRY OR EJECTION DATE
* (INPUT VARIABLE)
UXCMOUNT DS CL10 LAST MOUNTED DATE
* (INPUT/OUTPUT VARIABLE)
UXCWRITE DS CL10 LAST WRITTEN DATE
* (INPUT/OUTPUT VARIABLE)
UXCEXPIR DS CL10 VOLUME EXPIRATION DATE
* (INPUT FOR CHANGE TO SCRATCH
* OUTPUT FOR CHANGE TO PRIVATE)
DS CL10 RESERVED
DS CL4 RESERVED
UXCEXITI DS CL16 INFORMATION TO BE PASSED TO THE
* INSTALLATION EXIT
UXCLMOPM DS 0CL32 OUTBOARD POLICY MANAGEMENT
UXCLMSG DS CL8 LIBRARY MANAGER STORAGE GROUP
* TO CHANGE VALUE, USE UXCGROUP
* (INPUT VARIABLE)
UXCLMSC DS CL8 LIBRARY MANAGER STORAGE CLASS
* (INPUT/OUTPUT VARIABLE)
UXCLMMC DS CL8 LIBRARY MANAGER MANAGEMENT CLASS
* (INPUT/OUTPUT VARIABLE)
UXCLMDC DS CL8 LIBRARY MANAGER DATA CLASS
* (INPUT/OUTPUT VARIABLE)
DS 0D END OF UXCPL
UXCPLLEN EQU *-UXCPL
SPACE 1
***********************************************************************
* *
* RETURN CODES *
* *
***********************************************************************
UXCNOCHG EQU 0 CHANGE THE VOLUME USE ATTRIBUTE AS
* REQUESTED USING PARAMETER VALUES
* PASSED IN ON INPUT
UXCCHG EQU 4 CHANGE THE USE ATTRIBUTE AS
* REQUESTED BUT NOTE THAT PARAMETER
* VALUES HAVE BEEN RETURNED BY EXIT
UXCFAIL EQU 8 DO NOT CHANGE THE VOLUME USE
* ATTRIBUTE
* EQU 12 RESERVED
UXCDONT EQU 16 DO NOT CALL THE VOLUME USE
* ATTRIBUTE INSTALLATION EXIT
* AGAIN, BUT CHANGE THE USE
* ATTRIBUTE AS REQUESTED USING
* PARAMETER VALUES PASSED IN
* ON INPUT
SPACE 1
***********************************************************************
* *
* LIBRARY LOGICAL TYPE CONSTANTS *
* *
***********************************************************************
UXCREAL EQU C'R' AUTOMATED LIBRARY
UXCMAN EQU C'M' MANUAL LIBRARY
SPACE 1
***********************************************************************
* *
* USE ATTRIBUTE CONSTANTS *
* *
***********************************************************************
UXCPRIV EQU C'P' PRIVATE USE ATTRIBUTE
UXCSCRT EQU C'S' SCRATCH USE ATTRIBUTE
SPACE 1
***********************************************************************
* *
* TAPE DEVICE SELECTION INFORMATION CONSTANTS *
* *
***********************************************************************
UXNOCAR EQU 0 ZERO IS AN ACCEPTABLE TDSI VALUE
***********************************************************************
* CONSTANTS TO DEFINE RECORDING TECHNOLOGY *
***********************************************************************
UXCNOREC EQU 0 RECORDING TECHNOLOGY UNKNOWN OR
* UNSPECIFIED
UXC18TRK EQU 1 READ/WRITE ON 18-TRACK DEVICE
UXC36TRK EQU 2 READ/WRITE ON 36-TRACK DEVICE
UXC128TRK EQU 3 READ/WRITE ON 128-TRACK DEVICE
UXC256TRK EQU 4 READ/WRITE ON 256-TRACK DEVICE
UXC384TRK EQU 5 READ/WRITE ON 384-TRACK DEVICE
UXCEFMT1 EQU 6 READ/WRITE ON ENTERPRISE FORMAT 1
* (EFMT1) DEVICE
UXCEFMT2 EQU 7 READ/WRITE ON ENTERPRISE FORMAT 2
* (EFMT2) DEVICE
UXCEEFMT2 EQU 8 READ/WRITE ON ENTERPRISE ENCRYPTED FORMAT 2
* (EEFMT2) DEVICE
UXCEFMT3 EQU 9 READ/WRITE ON ENTERPRISE
* FORMAT 3 (EFMT3) DEVICE
UXCEEFMT3 EQU 10 READ/WRITE ON ENTERPRISE ENCRYPTED
* FORMAT 3 (EEFMT3) DEVICE
UXCEFMT4 EQU 11 READ/WRITE ON ENTERPRISE
* FORMAT 4 (EFMT4) DEVICE
UXCEEFMT4 EQU 12 READ/WRITE ON ENTERPRISE ENCRYPTED
* FORMAT 4 (EEFMT4) DEVICE
***********************************************************************
* CONSTANTS TO DEFINE MEDIA TYPE *
***********************************************************************
UXCNOMED EQU 0 MEDIA TYPE UNKNOWN OR UNSPECIFIED
UXCMED1 EQU 1 MEDIA1 - CARTRIDGE SYSTEM TAPE
UXCMED2 EQU 2 MEDIA2 - ENHANCED CAPACITY CARTRIDGE
* SYSTEM TAPE
UXCMED3 EQU 3 MEDIA3 - HIGH PERFORMANCE CARTRIDGE
* TAPE
UXCMED4 EQU 4 MEDIA4 - EXTENDED HIGH PERFORMANCE
* CARTRIDGE TAPE
UXCMED5 EQU 5 MEDIA5 - ENTERPRISE TAPE
* CARTRIDGE
UXCMED6 EQU 6 MEDIA6 - ENTERPRISE WORM TAPE
* CARTRIDGE
UXCMED7 EQU 7 MEDIA7 - ENTERPRISE ECONOMY
* TAPE CARTRIDGE
UXCMED8 EQU 8 MEDIA8 - ENTERPRISE ECONOMY
* WORM TAPE CARTRIDGE
UXCMED9 EQU 9 MEDIA9 - ENTERPRISE EXTENDED TAPE
* CARTRIDGE
UXCMED10 EQU 10 MEDIA10 - ENTERPRISE EXTENDED WORM TAPE
* CARTRIDGE
UXCMED11 EQU 11 MEDIA11 - ENTERPRISE ADVANCED
* TAPE CARTRIDGE
UXCMED12 EQU 12 MEDIA12 - ENTERPRISE ADVANCED
* WORM TAPE CARTRIDGE
UXCMED13 EQU 13 MEDIA13 - ENTERPRISE ADVANCED
* ECONOMY TAPE CARTRIDGE
***********************************************************************
* CONSTANTS TO DEFINE COMPACTION (THE MEANING OF THE *
* COMPACTION FIELD HAS CHANGED FROM TYPE OF COMPACTION *
* TO COMPACTION YES/NO - UXCIDRC AND UXCCOMPT *
* CAN BE USED INTERCHANGEABLY) *
***********************************************************************
UXCCMPNS EQU 0 COMPACTION UNKNOWN OR NOT SET
UXCNOCMP EQU 1 NO COMPACTION
UXCCOMPT EQU 2 COMPACTION
UXCIDRC EQU 2 COMPACTION
***********************************************************************
* CONSTANTS TO DEFINE SPECIAL ATTRIBUTE *
***********************************************************************
UXCNOSPC EQU 0 VOLUME HAS NO SPECIAL ATTRIBUTE
UXCRDCOM EQU 1 VOLUME WILL BE MOUNTED FOR READ ONLY -
* ALL READ-COMPATIBLE DEVICES MAY BE
* SELECTED
***********************************************************************
* *
* MISCELLANEOUS CONSTANTS *
* *
***********************************************************************
UXCPLSP EQU 230 UXCPL SUBPOOL NUMBER
UXCYES EQU C'Y' YES
UXCNO EQU C'N' NO
UXCBLANK EQU C' ' BLANK
SPACE 2
MEND ,Storage is obtained below the line, from subpool 230, user key, for the installation exit parameter list.