D.2 Basic Stream Functions

These generic functions must be defined for all stream classes. [annotate]

stream-element-type  stream [Generic Function]

This existing Common Lisp function is made generic, but otherwise behaves the same. Class fundamental-character-stream provides a default method that returns character. [annotate]


open-stream-p  stream [Generic Function]

This function is made generic. A default method is provided by class fundamental-stream that returns true if close has not been called on the stream. [annotate]


close  stream &key abort [Generic Function]

The existing Common Lisp function close is redefined to be a generic function, but otherwise behaves the same. The default method provided by the class fundamental-stream sets a flag used by open-stream-p. The value returned by close will be as specified by the X3J13 issue closed-stream-operations. [annotate]


stream-pathname  stream [Generic Function]
stream-truename  stream [Generic Function]

These are used to implement pathname and truename. There is no default method since these are not valid for all streams. [annotate]