The default tracing is TRACE N. If we don't have access to the GETFMADR module, then issuing the command will result into a return code -3, meaning 'Unknown CP/CMS command'.
As most programmers don't test the return code for "commands that never should fail" (such as GETFMADR, SET CMSTYPE,...) it remains possible to get a code -3 when the command module is not available.
With the default Normal tracing, we may get
10 *-* 'GETFMADR'
+++ RC(-3) +++
If however, we issue Trace Off, then the use will have no clue of why the procedure fails.
So, as explained in the lesson, TRACE OFF is not the best choice for your procedures.
Don't conclude however that with Trace N you get the return code while you don't get it with Trace Off. The return code is produced in both cases, but you not always see it.
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