Returns either a character from the stream, an
:eof
if the end-of-file is reached, or
nil
if no input is currently available.
The generic function
stream-read-char-no-hang
implements
read-char-no-hang
. It returns either a character read from the stream, or
:eof
if end-of-file is reached, or
nil
if no input is available. The default method provided by
fundamental-character-input-stream
simply calls
stream-read-char
which is sufficient for file streams, but interactive streams should define their own method.