
current_stream(?Stream)

   Succeeds if Stream is a currently open stream.



Arguments
   Stream              Atom, integer or variable.

Type
   Stream I/O

Description
   Used to test whether a given identifier denotes an open stream,
   or enumerates all currently open streams on backtracking.


   When called with a variable argument, only the physical stream
   numbers are returned, not the symbolic aliases.




Modes and Determinism
   current_stream(+) is semidet
   current_stream(-) is nondet

Fail Conditions
   Fails if Stream is instantiated but does not denote an open stream.

Exceptions
     5 --- Name is instantiated, but not to an atom or integer.

Examples
   
Success:
    [eclipse 1]: current_stream(S).
    S = 0     More? (;) 
    S = 1     More? (;) 
    S = 2     More? (;) 
    S = 3     More? (;) 
    S = 4     More? (;) 
    S = 5     More? (;) 
    no (more) solution.

    [eclipse 2]: current_stream(output).
    yes.

    [eclipse 3]: current_stream(junk).
    no (more) solution.





See Also
   open / 3, open / 4, get_stream_info / 3, get_stream / 2
