
get_stream(+StreamId, ?Stream)

   Succeeds if Stream is the stream to which the stream StreamId is assigned.



Arguments
   +StreamId           Atom or integer.
   ?Stream             Integer, atom or variable.

Type
   Stream I/O

Description
   StreamId is an existing logical or physical stream.  If Stream is a
   variable, then it is bound to the physical stream number corresponding
   to StreamId.  Otherwise, the predicate succeeds if StreamId denotes the
   same stream as the symbolic stream name or physical stream number
   Stream.


   The predefined logical system stream names are:


   input, output, error, warning_output, log_output,
   stdin, stdout, stderr, null



Resatisfiable
      No.

Fail Conditions
      Fails if Stream is not a stream with the stream identifier StreamId.



Exceptions
     4 --- One or both of StreamId and Stream is not instantiated.
     5 --- Stream is neither an atom, an integer nor a variable.
     5 --- StreamId is neither an atom nor an integer.
   193 --- StreamId is an illegal stream specification.

Examples
   
Success:
      [eclipse]: get_stream(input,X), set_stream(a,input),
      > get_stream(input,a).
      X = 0
      yes.

Fail:
      set_stream(b,4), get_stream(b, 10).

Error:
      get_stream(Id, S).      (Error 4).
      get_stream(1.0,S).      (Error 5).
      get_stream(3, S).       (Error 5).
      get_stream(blah,S).     (Error 193). % does not exist





See Also
   set_stream / 2
