Joined: 14 Jan 2008 Posts: 2504 Location: Atlanta, Georgia, USA
I know this is an old topic, but I was told recently by a CICS 'Expert' that the next release of CICS would be increasing the size of the COMMAREA up in the megabytes.
This would wreak havoc on current applications and I don't believe the expert's information is correct.
EIBCALEN would need to be redefined as a signed-fullword (currently, it's a signed-halfword). However, please understand that the current maximum value for EIBCALEN is 32763, with IBM encouraging a value of not more than 24576 (24K). Although the maximum value of a signed-halfword is 32767 (32K-1), IBM reserves a fullword (4-Bytes), resulting in 32763 (32K-5). A signed-halfword greater than 32767 will be considered a negative value (the high-order bit of the 1st-Byte is on) so keep this in mind. An unsigned-halfword has a maximum value of X'FFFF' (65535) and would be considered a negative one (-1) if it were addressed as a signed-halfword.
The current version/release of CICS/TS is 4.1 (released this past June) and EIBCALEN remains as it always has.
All of the offsets in DFHEIBLK would be off by 2-Bytes and the overall length of this DSECT would increase to decimal 87.
There are many DSECTS and Assembler labels which would need to be increased to accommodate this new DFHEIBLK, such as the commarea-DSECT for DFHPEP and the user-EIB commarea label in this commarea.
Having said this, IBM would need to back-fill previous releases to accommodate this increased EIBCALEN definition.
Also, when a commarea is passed from program to program, the address is not passed, rather the commarea gets recreated (via an internal CICS GETMAIN) upon each LINK and/or XCTL, would would cause a substantial increase in EUDSA if EIBCALEN were defined as a signed-fullword, maximum value of X'7FFFFFFF' and most likely (as with the halfword EIBCALEN), minus 4.
Please have the expert point us to some authentic IBM documentation and/or press releases (not just hearsay) so we can mull over this, but he'll probably come up short.