5.11 The STREAMS module
stream-position-setter
Open generic function
Summary
Sets the position of a stream.
Signature
stream-position-setter position positionable-stream
=> new-position
Arguments
- position
- An instance of
<position-type>. - positionable-stream
-
An instance of
<positionable-stream>.
Values
- new-position
- An instance of
<stream-position>, or an instance of<integer>.
Library
io
Module
streams
Description
Changes the stream's position for reading or writing to position.
When it is an integer, if it is less than zero or greater than positionable-stream.stream-size this function signals an error. For file streams, a <stream-position-error> is signalled. For other types of stream, the error signalled is <simple-error>.
When position is a <stream-position>, if it is invalid for some reason, this function signals an error. Streams are permitted to restrict the position to being a member of the set of values previously returned by calls to stream-position on the same stream.
The position may also be #"start", meaning that the stream should be positioned at its start, or #"end", meaning that the stream should be positioned at its end.
Note: You cannot use stream-position-setter to set the position past the current last element of the stream: use adjust-stream-position instead.