![]() So interactive queries to such streams might not have the expected effect. Output to batch streams is typically discarded or saved for later viewing, Streams containing batch (or background or command-file) input. Interactive streams is to allow them to be distinguished from ![]() The general intent of having some streams be classified as Instead of immediately returning a character or end-of-file. * read-char might wait for the user to type something before returning The program is expected to prompt for input and support "normal input editing". That the program can prompt for information and expect to receive different The stream is connected to a person (or equivalent) in such a way Implementation might choose to use as identifying characteristics Implementation-defined, and may depend on the underlying The precise meaning of an interactive stream is Is one on which it makes sense to perform The result might be different for an open streamĪnd for that same stream once it has been closed. In some situations, such as for a truename computation, The consequences are undefined when a closed stream Structures, and to free any external resources which might have been locked by theĮxcept as explicitly specified otherwise, Or sink of data, permitting the implementation to reclaim its internal data ![]() The action of closing a stream marks the end of its use as a source Operations that create and return streams return open streams. Streams are either as explicitly specified otherwise, Shows a list of operators that relate specificaly toįigure 21-4: Operators relating to Bidirectional Streams. Is called a the functions input-stream-p and output-stream-p.Īny of the operators listed in Figure~21-2 or Figure~21-3Ĭan be used with bidirectional streams. Peek-char read-char-no-hang read-preserving-whitespaceįigure 21-2: Operators relating to Input Streams.įigure 21-3: Operators relating to Output Streams.Ī stream that is both an input stream and an output stream Or ( e.g., when " :direction :probe" is given to open) neither. Other operations are only meaningful on certain stream types.įor example, read-char is only defined for character streamsĪnd read-byte is only defined for binary streams.Ībstract Classifications of Streams Input, Output, and Bidirectional StreamsĪ stream, whether a character stream or a binary stream, That are potentially useful with any kind of stream.įigure 21-1: Some General-Purpose Stream Operations Some operations may be performed on any kind of stream įigure 21-1 provides a list of standardized operations Streams Stream Concepts Introduction to StreamsĪ an object that can be used with an input or outputįunction to identify an appropriate source or sink of characters or Go to the first, previous, next, last section, table of contents. ANSI and GNU Common Lisp Document - Streams
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