/usr/local/lib/swipl/library/csv.pl
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 csv_write_stream(+Stream, +Data, +Options) is det
Write the rows in Data to Stream. This is similar to csv_write_file/3, but can deal with data that is produced incrementally. The example below saves all answers from the predicate data/3 to File. 
save_data(File) :-
   setup_call_cleanup(
       open(File, write, Out),
       forall(data(C1,C2,C3),
              csv_write_stream(Out, [row(C1,C2,C3)], [])),
       close(Out)).