5.11 The STREAMS module
unread-element
Open generic function
Summary
Returns an element that has been read back to a positionable stream.
Signature
unread-element positionable-stream element => element
Arguments
- positionable-stream
-
An instance of
<positionable-stream>. - element
- An instance of
<object>.
Values
- element
- An instance of
<object>.
Library
io
Module
streams
Description
"Unreads" the last element from positionable-stream. That is, it returns element to the stream so that the next call to read-element will return element. The stream must be a <positionable-stream>.
It is an error to do any of the following:
- To apply
unread-elementto an element that is not the element most recently read from the stream. - To call
unread-elementtwice in succession. - To unread an element if the stream is at its initial position.
- To unread an element after explicitly setting the stream's position.