The first parameter of the C/C++ function for a UDM is always the handle of the UDT on which the UDM is invoked. The UDM uses the UDT handle to get the values of the UDT on which it is invoked.
The parameters that follow the UDT handle parameter correspond to the parameter list in the METHOD specification of the CREATE TYPE statement.
Use parameter style SQL to allow a method to pass nulls for arguments; otherwise, use parameter style TD_GENERAL.
When you use parameter style SQL, you must define indicator parameters for each parameter.