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read-line (Function)

— Function: 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.


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).

 (setq a "line 1
 "line 1
 (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
Affected By:

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

Exceptional Situations:

If an end of file2 occurs before any characters are read in the line, an error is signaled if eof-error-p is true.

See Also:



The corresponding output function is write-line.