A stream is an object that can be used with an input or output function to identify an appropriate source or sink of characters or bytes for that operation. A character stream is a source or sink of characters. A binary stream is a source or sink of bytes.
Some operations may be performed on any kind of stream; Figure 21–1 provides a list of standardized operations that are potentially useful with any kind of stream.
| close | stream-element-type |
| input-stream-p | streamp |
| interactive-stream-p | with-open-stream |
| output-stream-p |
Other operations are only meaningful on certain stream types. For example, read-char is only defined for character streams and read-byte is only defined for binary streams.
| Abstract Classifications of Streams (Introduction to Streams) | ||
| Input | ||
| Open and Closed Streams | ||
| Interactive Streams | ||
| Abstract Classifications of Streams | ||
| File Streams | ||
| Other Subclasses of Stream |