Using the COMMAREA in RETURN commands

The COMMAREA option of the RETURN command is designed specifically for passing data between successive transactions in a pseudoconversational sequence. It is implemented as a special form of user storage, although the EXEC interface, rather than the application program, issues the GETMAIN and FREEMAIN requests.

The COMMAREA is allocated from the CICS® shared subpool in main storage, and is addressed by the TCTTE, between tasks of a pseudoconversational application. The COMMAREA is freed unless it is passed to the next task.

The first program in the next task has automatic addressability to the passed COMMAREA, as if the program had been invoked by either a LINK command or an XCTL command (see COMMAREA in LINK and XCTL commands). You can also use the COMMAREA option of the ADDRESS command to obtain the address of the COMMAREA.

For a COMMAREA passed between successive transactions in a pseudoconversational sequence in a distributed environment, z/OS® Communications Server for SNA imposes a limit of 32KB on the size of the total data length. This limit applies to the entire transmitted package, which includes control data added by Communications Server. The amount of control data increases if the transmission uses intermediate links.