rowtype and ecpg - Mailing list pgsql-sql

I have a function that takes as a parameter ROWTYPE:

create or replace function test_func(test_table) 
returns varchar as '
declare  lv_return   varchar;
begin  ......  return lv_return;
end;
' LANGUAGE 'plpgsql';

How do I call this function from the C program (ecpg)? How my
declaration should look like?

I trued structure and got error: Too many arguments

Thanks for your help