CLHS: Function READ-LINE

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Function READ-LINE

Syntax:

read-line `&optional` input-stream eof-error-p eof-value recursive-p

=> line, missing-newline-p

Arguments and Values:

input-stream---an input stream designator. The default is standard input.

eof-error-p---a generalized boolean. The default is true.

eof-value---an object. The default is nil.

recursive-p---a generalized boolean. The default is false.

line---a string or the eof-value.

missing-newline-p---a generalized boolean.

Description:

Reads from input-stream a line of text that is terminated by a newline or end of file.

If recursive-p is true, this call is expected to be embedded in a higher-level call to read or a similar function used by the Lisp reader.

The primary value, line, is the line that is read, represented as a string (without the trailing newline, if any). If eof-error-p is false and the end of file for input-stream is reached before any characters are read, eof-value is returned as the line.

The secondary value, missing-newline-p, is a generalized boolean that is false if the line was terminated by a newline, or true if the line was terminated by the end of file for input-stream (or if the line is the eof-value).

Examples:

     (setq a "line 1
     line2")
    =>  "line 1
     line2"
     (read-line (setq input-stream (make-string-input-stream a)))
    =>  "line 1", false
     (read-line input-stream)
    =>  "line2", true
     (read-line input-stream nil nil)
    =>  NIL, true

Side Effects: None.

Affected By:

*standard-input*, *terminal-io*.

Exceptional Situations:

If an end of file[2] occurs before any characters are read in the line, an error is signaled if eof-error-p is true.

See Also:

read

Notes:

The corresponding output function is write-line.

The following X3J13 cleanup issue, not part of the specification, applies to this section:

- ARGUMENTS-UNDERSPECIFIED:SPECIFY

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