Using the programmable interface to CEDA

The resource definition online (RDO) transaction, CEDA has a programmable interface that you can use to invoke the functions provided by RDO from an application program.

The CSD update batch utility program DFHCSDUP and the EXEC CICS CSD commands are the preferred methods to examine and amend CSD files. DFHCSDUP can be used to update CSD files in bulk. DFHCSDUP can be invoked from a user program, running either in batch mode or under TSO.

To invoke the programmable interface to CEDA, use this command:
EXEC CICS LINK PROGRAM('DFHEDAP')
               COMMAREA(cedaparm)
where DFHEDAP is the name of the entry point in the RDO program, and cedaparm is a user-defined name of a parameter list consisting of five 31-bit addresses (each contained in a fullword) as follows:
  1. Address of a field containing the RDO command in source form.
  2. Address of a halfword binary field specifying the length of the command. The maximum length of the input command is 1022 bytes.
  3. Address of a 1-byte indicator field defined as follows:
    X'80'
    Display output at terminal instead of returning it to caller.
    X'00'
    Do not display output at terminal.
  4. Address of a field in which output is to be placed by DFHEDAP.
  5. Address of a halfword binary field specifying the maximum length of output that the application can handle.

If the indicator in address 3 is X'80', output is displayed at the terminal. In this case, you can enter any number of CEDA commands at the terminal, in response to the output displayed on your screen. Control is returned to your application program when you press PF3.

However, if the indicator is X'00' (output is not to be displayed at the terminal), DFHEDAP returns control to your application program immediately after processing the RDO command specified in the first address. At the same time, DFHEDAP returns the output as one or two concatenated, structured fields. The output from a single request comprises one field for the translation stage and one or none for the execution stage. Each field has the format:
  • Binary halfword containing inclusive length of field.
  • Binary halfword containing the number of messages produced.
  • Binary halfword containing the highest message-severity: ‘0' and ‘4' continue to execution; ‘8' and ‘12' do not continue to execution.
  • Variable-length data containing:
    • For the translation stage: diagnostic messages if there are any.
    • For the execution stage: data that would normally appear on the CEDA screen, including messages. Each line begins with a new line (NL) character and, otherwise, consists of blanks and uppercase alphanumeric characters.
The format of this data is not guaranteed from release to release, but it is the same as that displayed by CEDA. (Analysis of this data should not normally be necessary. Typically, your program is interested only in whether or not the command was successful.) If the total output is longer than the maximum length specified by the user, it is truncated.
Note:
  1. An attempt to start CEDA from an application program by an EXEC CICS START command must fail. This is because CEDA's first action is to request input from its associated terminal, whereas an automatically initiated transaction must first send data to the terminal.

    An attempt to start CEDA under CECI by an EXEC CICS START command fails for similar reasons.

  2. The RDO command passed in address 1 of the CEDAPARM parameter list must be valid. (For example, spelling errors such as PRORGAM for PROGRAM are not corrected automatically when you use the programmable interface.)
  3. You cannot use the programmable interface to change the values of CEDA keywords that are obsolete in this release of CICS®, but which are retained for compatibility with earlier releases. That is, the interface does not support compatibility mode.
  4. CEDA issues various syncpoints as part of its processing. Therefore, when your program links to DFHEDAP the current unit of work (UOW) of the transaction is completed. This may result in problems if, for example, there are outstanding browse operations against VSAM data sets.