COMMAREA (DFHCOMMAREA). The commarea is used to pass user data between programs. The Commarea is specified in the LINKAGE SECTION of your program. There will always be a DFHCOMMAREA in your program whether you specify it or not. If you don?t specify a DFHCOMMAREA in the program then a one byte DFHCOMMAREA is placed in the Linkage Section at compile time. (The compiler will also insert the USING DFHCOMMAREA after the Procedure Division statement).
The maximum size of DFHCOMMAREA is 32K, however it is recommended (by IBM) that it not exceed 24K. The length of the Commarea is returned to your program in the variable EIBCALEN.
This COMMAREA Link from one of your application programs to another, either locally or remotely, anticipating subsequent return to the requesting program (EXEC CICS LINK).