Using input data sets in a TSO-environment REXX check

A REXX check running in a TSO environment (REXXTSO(YES)) can use TSO services. A REXXTSO(YES) check can allocate and read from or write to any data set that it can access When there is a lot of input parameter data, we recommend that the check parameter be the name of the data set and the exec would allocate and read from that data set to access its parameters. For example, lets say a TSO REXX check is defined with the PARMS parameter, as follows:

PARMS('DSN(IBMUSER.HZSSXCHK.DATA)')

Based on the data set specified in PARMS, the REXX check uses data set IBMUSER.HZSSXCHK.DATA as its input data set.

In order to get consistent results from your REXX checks, IBM® suggests that the exec has exclusive access to the input data set. If the system cannot allocate or use a requested input data set, the REXX check does not run successfully.