character—a character.
output-stream—an output stream designator. The default is standard output.
write-char
outputs character to output-stream.
(write-char #\a) ▷ a → #\a (with-output-to-string (s) (write-char #\a s) (write-char #\Space s) (write-char #\b s)) → "a b"
The output-stream is modified.
*standard-output*
,
*terminal-io*
.