The list of parameters for a UDF is very specific. It includes the input parameters that Teradata Database passes when the UDF appears in a DML statement. It also includes output parameters that return the result of the UDF and the SQLSTATE result code.
A UDF can have 0 to 128 input parameters. The types that you use as input parameters and return type of a UDF correspond to SQL data types in the function call. For details, see SQL Data Type Mapping.
Additional parameters might be required, depending on the parameter passing convention you choose.
Parameters are almost always specified as pointers to the data.