Makes file FileOrStream the current output stream.
If there is an open output stream associated with FileOrStream,
and that stream was opened by
tell/1, then it is made the
current output stream. Otherwise, the specified file is opened for
output in text mode with default options and made the current output stream.
Different file names (that is, names that do not unify) represent different streams (even if they correspond to the same file). Therefore, assuming food and ./food represent the same file, the following sequence will open two streams, both connected to the same file.
tell(food) ... tell('./food')
It is important to remember to close streams when you have finished with
fileerrorsProlog flag is