How to use LINK MODULE

Assume you have installed GDDM and CICS®, and some of the GDDM modules must be linked into CICS load modules. GDDM resides in zone GDDTZN, and the zone controlling CICS is CICTZN. Because GDDM and CICS are controlled by different zones, SMP/E does not automatically link the GDDM modules into the CICS load modules when GDDM is installed. The LINK MODULE command can be used instead.

In this example, GDDM module ADMABCD needs to be linked into CICS load module DFHWXYZ. Module ADMABCD is installed in a target library as a single-CSECT load module when GDDM is installed. Therefore, SMP/E can use the target library version of ADMABCD to update CICS load module DFHWXYZ. (If a module does not reside in a target library as a single-CSECT load module, SMP/E uses the related distribution zone copy of the module to update the load module.)

The following commands can be used to have SMP/E install and track the installation of GDDM module ADMABCD in the CICS load module:

SET   BDY(CICTZN)         /* Target zone for CICS.      */.
LINK  MODULE(ADMABCD)     /* Link module ADMABCD        */
      FROMZONE(GDDTZN)    /* residing in zone GDDTZN    */
      INTOLMOD(DFHWXYZ)   /* into load module DFHWXYZ.  */.

These commands cause GDDM module ADMABCD to be linked into CICS load module DFHWXYZ. SMP/E also adds cross-zone subentries to the affected entries:

An XZLMOD subentry is added to the ADMABCD MOD entry in target zone GDDTZN so that if ADMABCD is updated, it can be automatically replaced in the CICS load module.
Note: The CICS load module is automatically updated only if the XZLINK subentry was previously set to AUTOMATIC in the TZONE entry for zone CICTZN. Here is an example of the commands that can be used to do this:
```
SET  BDY(CICTZN)        /* Target zone for CICS.    */.
UCLIN.
ADD  TZONE(CICTZN)      /* Update TZONE entry       */
     XZLINK(AUTOMATIC). /* to do automatic links.   */.
ENDUCL.
```
An XZMOD subentry is added to the CICS DFHWXYZ LMOD entry in target zone CICTZN to indicate that:
- DFHWXYZ now contains ADMABCD.
- Any updates for ADMABCD should be accepted only from zone GDDTZN.
TIEDTO subentries are added to the TZONE entries for CICTZN and GDDTZN to indicate that there is a relationship between modules and load modules in these zones.

For more information about the LINK MODULE command and cross-zone updating during APPLY and RESTORE processing, see the LINK MODULE topic in SMP/E for z/OS Commands.