open_null_stream/1
open_null_stream(-Stream)
opens an output text stream that is not connected to any file and unifies its stream object with Stream.
stream_object
Characters or terms that are sent to this stream are thrown away.
This predicate is useful because various pieces of local state are
kept for null streams: the predicates
character_count/2
, line_count/2
, and
line_position/2
can be used on these streams.
uninstantiation_error
Stream is not a variable
system_error
Unexpected error detected by the operating system