Guidelines for defining stdin, stdout, and stderr

For BPXBATCH, the default for stdin and stdout is /dev/null.

The default for stderr is the same as what is defined for stdout. For instance, if you define stdout to be /tmp/output1 and you do not define stderr, then both printf() and perror() direct their output to /tmp/output1.

Rule: If you define stdin, it must be a z/OS UNIX file.

If you define stdout or stderr, it can be a z/OS UNIX file or an MVS™ data set.

If you use an MVS data set for stdout or stderr:

It can be a sequential data set, a partitioned data set (PDS) member, a partitioned data set extended (PDSE) member, or SYSOUT.
It must have a nonzero logical record length (LRECL) and a defined record format (RECFM). Otherwise, BPXBATCH will redirect the DD to/dev/null and issue message BPXM081I, indicating the redirection of the effected ddname.