The standard function
is implemented as a generic function. All external resources used by the stream should be freed and true returned when that has been done. The result value for
is as per the Common Lisp ANSI specification.
is an instance of a subclass of buffered-stream, if
is true then any remaining data in the buffer can be discarded. There are two built-in methods on buffered-stream. The primary method specialized on buffered-stream returns
. The other, an
method specialized on buffered-stream, flushes the stream buffer if
, calls the next method and marks the stream as closed if that method returns true. Thus the only requirement for a primary method specialized on a subclass of buffered-stream is that it must close any underlying data source and return true.