]> > close_out and close_in both perform the equivalent of a Unix.close on > the underlying Unix file descriptor, and, yes, closing something that > is already closed is an I/O exception. So, one possibility is to > close only one of the three entities file_descr, oc and ic. It's best > to close the output channel oc, since this will flush its buffer. What I did was just skipping the Unix.close, but close *both* in- and out-channels and it worked (until now ;-) ). > Side remark: you'd need to close the file descriptor also in the case > where the line is found and the exception Found is raised. Yup, I've seen this one already. This one makes it complicated, since for propagating the exception, I have to duplicate the closings: . . . with End_of_file -> output_string oc (line ^ "\n"); Found line -> (close_out oc; close_in ic; raise Found line); close_out oc; close_in ic Since I am new to streams & co, are there any kind of rules when to prefer streams to normal I/O? Is there more overhead when using streams? Shouldn't I use streams when working on a regular text file? What if I want to break from a stream with an exception (as above the Found exception)? Closing/accessing the channel is only possible in the stream creation as in my corrected version: let read_lines ch = let read_new_line n = try Some (input_line ch) with End_of_file -> close_in ch; None in Stream.from read_new_line Now I want to stop reading lines after a certain number of lines let rec read_n_lines n = parser [< 'line; rest >] -> if n <> 0 then print_endline line; read_n_lines (n-1) else () [< >] -> () Didn't type-check it, though ;-) Anyway, how can I close the stream in this case? Thanks! - Chris ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners