The APPC/MVS application programming interface (API) trace facility allows programmers to more easily diagnose problems with APPC/MVS TPs, by collecting data about APPC/MVS or CPI-C calls that an APPC/MVS TP issues. Through the ATBTRACE REXX exec, programmers can start tracing activity for only specific TPs or users, or for many TPs, many conversations, and many users. They can stop or list the status of tracing activity through the exec, as well.

If necessary, see z/OS MVS Programming: Writing Transaction Programs for APPC/MVS for more information about using the API trace facility.