Reads a character from a serial port.
A serial-port object.
reads and returns a character from the serial port associated with
A timeout will occur if the character is not available before the read timeout (as specified by values given when the serial port was opened by open-serial-port).
When a timeout occurs, if
is non-nil, then an error of type
is signalled, otherwise
is returned. The default value of
LispWorks User Guide and Reference Manual - 21 Dec 2011