Rowset functions in Firebird

Question

I have table like data coming from a c++ module and I want to use this in Firebird SQL queries/stored procedure.

Firebird allows hooking c++ code through UDFs. But it can return only a single value. I am planning to return xml string value from UDF, populate this in global table and use it for any use.

Is this right way of doing? Are there any alternative approaches to do this?

Thanks in advance

-Gopala