During the LNKEDT step for USRIDXIT with IDMSSTRT getting the following:
UNRESOLVED EXTERNAL REFERENCES EXTRN TMMCEP1
Release : 18.5
Component : IDMS/DB
Up to IDMS 17.0 the USRIDXIT is enabled for batch jobs by linking it together with module IDMSSTRT.
SQLIWXTR is a weak external so it's not a problem if it's unresolved.
For the unresolved reference to TMMCEP1 add:
For IDMS 18.0 and later releases, the USRIDXIT is enabled by linking it together with module IDMSUXIT and must have an entry point of USRIDXIT.
See IDMS documentation USRIDXIT, Entry Point Names, Named User Exit Enablement and IDMSUXIT Module Creation.