Differences between CICS, IMS TM, and MVS

For the most part, the use of Gateway-Library functions in CICS, IMS TM, and MVS is the same. The minor differences that exist are discussed in Table 1-1 and noted in the reference pages for the affected functions.

**Table 1-1: Coding differences between CICS, IMS TM, and MVS**
Function	Difference between CICS, IMS TM, and MVS
TDINFRPC TDSTATUS	The action taken when the communication state (COMM-STATE) is TDS-RESET can differ between CICS, MVS and the IMS TM implicit API: Under CICS, MVS, and the IMS TM explicit API, the transaction exits as soon as possible. Under the IMS TM implicit API, the transaction can call TDGETREQ to accept another client request or it can exit.
TDINIT	The first argument differs between CICS and IMS TM: Under CICS, the communications I/O block, passed as the first parameter in TDINIT, is the EIB (DFHEIBLK). Under IMS TM, the first TDINIT parameter is I/O PCB (IO-PCB). Under MVS, a null pointer should be used.
TDSETPT	Used with IMS TM only, to indicate the type of IMS TM transaction.
TDSNDDON	Value of CONN-OPTIONS in CICS, MVS, and the IMS TM explicit API can be set to TDS-ENDREPLY in long-running transactions. TDS-ENDREPLY cannot be used under the IMS TM implicit API. To learn how to simulate long-running transactions in the implicit API, see “Long-running transactions”.
TDINFACT TDSETACT	Accounting records are written to different logs under CICS, IMS TM, and MVS: Under CICS, accounting functions use VSAM files as log files. The default file name is SYTACCT1. Under IMS TM, accounting functions use the IMS TM log. Under MVS, the records are written to a sequential file. The DDNAME of this file is specified as a parameter in TDCUSTOM.
TDINFLOG TDINFSPT TDLSTSPT TDSETLOG TDSETSPT TDWRTLOG	Trace records are written to different logs under CICS, IMS TM, and MVS: Under CICS, tracing functions use VSAM files as log files. The default file name is SYTDLOG1. Under IMS TM, tracing functions use the IMS TM log. Under MVS, the records are written to a sequential file. The DDNAME of this file is specified as a parameter in TDCUSTOM.