Did you know that it is possible to install CICS definitions without using the CEDA transaction and without doing a shutdown and restart of CICS. This is a feature that has been around for almost ten years starting at least in version 3.3 of CICS. You can read all about "The programmable interface to the RDO transaction" in the Customization Guide. The beaty of this interface is that you can make your own install transaction without needing any kind of access to the CEDA transaction. The interface can carry out all the same commands as CEDA, but install is the only interesting one, because the batch interface DFHCSDUP cannot issue an install, although it can carry out all the nessecary commands to manipulate CICS definitions.

The interface is called by using an EXEC CICS LINK to program DFHEDAP. The COMMAREA must consist of five storage addresses. These five addresses must reference their own piece of storage and through these five storage areas you must communicate with DFHEDAP. You must use pointers and related stuff to make it work from COBOL or PL/1, but it is indeed possible.

At the end of this tip I will give the usual words of advise. You have to read the whole chapter about "The programmable interface to the RDO transaction" before starting. You must be aware that the interface executes SYNCPOINTS when it finds it nessecary (which is probably not when you do). This fact can cause a lot of headache if you are using DB2 in the same transaction. You must also be aware that if the output area that you supply is smaller than the actual amount of output, then the interface wraps around and overlays the area from the beginning. The result is that return codes are lost. Because communication with DFHEDAP is carried out using pointers you must ensure that the storage areas are located at the same CICS as you are executing the DFHEDAP program on.