Predefined values are IBM-defined fixed values that have predefined uses in the CL and are considered to be reserved in the i5/OS™ operating system.
Predefined values have an asterisk (*) as the first character in the value followed by a word or abbreviation, such as *ALL or *PGM. The purpose of the * in predefined values is to prevent possible conflicts with user-specified values, such as object names. Each predefined value has a specific use in one or more command parameters, and each is described in detail in the command description.
Some predefined values are used as operators in expressions, such as *EQ and *AND. The predefined value *N is used to specify a null value and can be used to represent any optional parameter. A null value (*N) indicates a parameter position for which no value is being specified; it allows other parameters that follow it to be entered in positional form. To specify the characters *N as a character value (not as a null), the string must be enclosed in apostrophes ('*N') to be passed. Also, when the value *N appears in a CL program variable at the time it is run, it is always treated as a null value.