read-line &optional input-stream eof-error-p eof-value recursive-p
⇒ line, missing-newline-p
| 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
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
*standard-input*, *terminal-io*.
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.
The corresponding output function is write-line.