This section describes a programmable interface to the resource definition
online (RDO) transaction, CEDA. The functions provided by RDO can be invoked
from application programs, by a command such as:
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:
- Address of a field containing the RDO command in source form.
- Address of a halfword binary field specifying the length of the command.
The maximum length of the input command is 1022 bytes.
- 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.
- Address of a field in which output is to be placed by DFHEDAP.
- 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.
Notes:
- 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.
- 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.)
- 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.
- 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 datasets.

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