The output mask used to present the formatted data value of a field in a list, report or output command.
The applicable masking pattern characters depend on the data type (Type) of the field (e.g., char, varchar, alpha, varalpha, numeric, int, longint, vastint, or date).
For a more detailed explanation of mask patterns and their relation to data types, see Masking.
The FieldMask is used automatically unless an explicit mask has been applied:
If FieldMask is $Null, the field will be output without masking unless only an explicitly programmed mask will be used, if provided.