Handling opaque-type arguments

When the routine manager receives opaque-type data for a C UDR, the way the routine manager passes this data to the UDR depends on the opaque data type, as follows:

• For fixed-length opaque types, the routine manager usually passes a pointer to the internal format of the opaque type.
• For varying-length opaque types, the routine manager passes a pointer to an mi_bitvarying varying-length structure.