# Class Netchannels.output_filter

    class output_filter : io_obj_channel -> out_obj_channel -> out_obj_channel

An `output_filter` filters the data written to it through the `io_obj_channel` (usually a `pipe`), and writes the filtered data to the passed `out_obj_channel`.

If the filter is closed, the `io_obj_channel` will be closed, too, but not the destination `out_obj_channel` (so you can still append further data).