r used.

<p>For more complicated situations, the application may need to pass data
in a user-defined type. The strong type checking of Fortran does not allow
passing an arbitrary type without modifying the Fortran interface for each
desired type. So the Fortran interface provides a type to be used for this
purpose, <b>Zoltan_User_Data_1</b>. Since different types of data may need
to be passed to different query functions, four such types are provided,
using the numerals 1, 2, 3 and 4 as the last character i