IBM S544-5285-01 - Manual (Page 95)

trc (Bytes 49–51)
The value of the trc parameter as specified on the acif command. ACIF uses
the default value if this parameter is not explicitly specified.
Notes:
1. Each of the previous character values is left-justified; that is, padding blanks
are added to the end of the string. For example, if pagedef=P1TEST is
specified on the acif command, the page definition value in the above data
structure is ‘P1TEST’.
2. Exit programs cannot change the values supplied in this data structure. For
example, if ‘P1TEST’ is the page definition value, and an exit program changes
the value to ‘P1PROD’, ACIF still uses ‘P1TEST’.
3. This data structure is provided for informational purposes only.
Chapter 4. User Exits and Attributes of the Input Print File in AIX 75