Constructs a ByteStream for accessing the file named url#. Arguments url# and mode# are similar to the arguments of the well known stdio function fopen#. In addition a url of #-# will be interpreted as the standard output or the standard input according to mode#. This constructor will open a stdio file and construct a ByteStream object accessing this file. Destroying the ByteStream object will flush and close the associated stdio file. Returns an error code if the stdio file cannot be opened.
Referenced by ByteStream::create().