The IKJADTAB Parameter List

On entry to IKJADTAB, register 1 must point to an IKJADTAB parameter list that you have built.

Figure 1 shows the standard parameter list structure for IKJADTAB.

Figure 1. Parameter List Structure for IKJADTAB

You must turn on the high-order bit of the last address in the parameter list to indicate the end of the list.

Use the IKJADFMT mapping macro, which is provided in SYS1.MACLIB, to map the parameter list for IKJADTAB. IKJADFMT has the following syntax: 
    IKJADFMT    [ADMAXCNT=xx]
ADMAXCNT=xx
specifies the number of elements in the array of table tokens. ADMAXCNT=1 is the default.

Table 1 shows the names and descriptions of the IKJADTAB parameters.

Table 1. The parameters for IKJADTAB
Parameter Function
ADTAB_FUNCTION An 8-byte character string that indicates the function to be performed. Set the contents of the 8-byte field to one of the following EBCDIC values:
Value
Function
NEWTABLE
Create a new table. If your program uses the ADTAB_LIKE parameter to specify a model table, IKJADTAB copies the contents of the model table into the new table. Otherwise, IKJADTAB initializes a new table.
ADD_LOAD
If a table to contain alternative libraries does not exist, create one. IKJADTAB adds the DCB address, which you specify in the ADTAB_LOADLIB parameter, to the table.
ENDTABLE
Remove one or more tables.
ALLTABLS
Remove all tables. IKJADTAB removes tables created by your program and by callers of your program.
ADTAB_LIKE A fullword containing the token for a model alternative library table. Use this parameter to pass alternative library definitions to a new environment. Specify the ADTAB_LIKE parameter with the NEWTABLE function to copy the contents of the model table into the new table being created.
The calling program must set the token for the model table to zero if:
  • You use the NEWTABLE function to initialize a new alternative library table.
  • You specify a function other than NEWTABLE.
ADTAB_LOADLIB A fullword containing the address of the DCB for an alternative load module library. Use this parameter with the ADD_LOAD function to place the DCB address for a load module library in an existing or newly created alternative library table. If you specify a function other than ADD_LOAD, you must set the address of the DCB to zero.
ADTAB_COUNT A fullword containing the number of tables to be freed. Use this parameter with the ENDTABLE function to specify the number of tables to be freed. Use the ADTAB_ARRAY parameter to specify the tokens for the tables to be freed. If you specify a function other than ENDTABLE, you must set the number of tables to zero.
ADTAB_ARRAY An array of table tokens. Each element of the array is a fullword containing the token for a table to be freed. Use this parameter with the ENDTABLE function to specify the tokens for the tables to be freed. Use the ADTAB_COUNT parameter to specify the number of tables to be freed. When IKJADTAB successfully frees a table, it sets the corresponding token in the parameter list to zero. If you specify a function other than ENDTABLE, you must set the value of the first array element to zero.
ADTAB_ECTADDR A fullword containing the address of the current ECT under which the ALTLIB environment is to be created or removed. This parameter is optional. If you do not specify this parameter, or if you specify a binary zero as the ECT address, IKJADTAB uses the system ECT.
ADTAB_ABEND A fullword containing the hexadecimal abend code issued by IKJADTAB. IKJADTAB sets this parameter only when it sets a return code of 100 (decimal) or 104 (decimal). A return code of 100 indicates that a parameter is in inaccessible storage. A return code of 104 indicates an internal IKJADTAB error.

This parameter is optional. If you do not specify this parameter, IKJADTAB will not return an abend code when it sets a return code of 100 or 104.
ADTAB_REASON_ A fullword containing the hexadecimal abend reason code issued by IKJADTAB. IKJADTAB sets this parameter only when it sets a return code of 100 (decimal) or 104 (decimal). A return code of 100 indicates that a parameter is in inaccessible storage. A return code of 104 indicates an internal IKJADTAB error.

This parameter is optional. If you do not specify this parameter, IKJADTAB will not return an abend reason code when it sets a return code of 100 or 104.
Notes: IKJADFMT provides a bounded parameter list, which means that you must indicate the number of tables to be freed at the time the parameter list is built. If your program cannot determine the number of tables to be freed before building the parameter list, perform the following steps:
  1. Use the IKJADFMT mapping macro specifying ADMAXCNT=1.
  2. Obtain sufficient virtual storage for the array of table tokens.
  3. Modify the ADTAB_COUNT parameter to reflect the number of tables to be freed.
  4. In the parameter list, set the pointer to the array data (ADTAB_ARRAY@ field) to the address of the virtual storage obtained for the array.