SICStus Prolog streams are divided into two categories, those opened by
tell/1 and those opened by
open/[3,4]. A stream
in the former group is referred to by its file specification,
while a stream in the latter case is referred to by its stream
object (see the figure “Categorization of Stream Handling Predicates”).
For further information about file specifications, see
ref-fdi. Stream objects are discussed in
ref-iou-sfh-sob. Reading the state of open streams is discussed
Each operating system permits a different number of streams to be open.