iolib.termios - an iolib (
extension for RS-422/485/232 (aka serial) interfaces - i.e. termios (3)
api common lisp wrappers.  It is still proof of concept now, and
there is no documentation either, except for docstrings and this readme.

I started writing this stuff in order to make my code for communication
with some embedded devices with via RS-422/485 interface not depended
on implementation (I used some sbcl wrappers from sb-posix:  In other words the main purpose of
the iolib.termios is more likely to provide a portable way to talk with
modem from lisp, than to cover all termios features.


Each instance of the `dual-channel-tty-gray-stream' stores original
termios settings (baud rates, control characters values etc.) and
the call of `close' on such stream will restore this settings.
`*open-serial-streams*' variable give you access to the list of all open
instances of the `dual-channel-tty-gray-stream', so you can call
(map 'nil #'close *open-serial-streams*) or something like that
in signal handler.

If you specify `read-timeout' & `write-timeout' options of the
`dual-channel-tty-gray-stream' (via `setf'), then
`stream-read/write-sequence' methods (from iolib.base package) will
poll stream `fd' for corresponding i/o operation with specified timeout
values before reading/writing.

Usage of `with-serial-stream' macro is recommended. Syntax is like
 (with-serial-stream (stream path &key
 	               (speed :b115200)
		       (parity :n)
		       (byte-size 8)
		       (flag (logior o-rdwr o-nonblock o-noctty))
                       (mode *default-open-mode*)
                       (external-format :default)
		       timeout read-timeout write-timeout)
    &body body)

I.e. only serial device pathname is necessary parameter.  You can
specify require baud rate (in keyword form: `:b9600` and so),
byte/character size and parity checking mode. Also you can turn on
hardware/software flow control and specify additional stream
parameters. Note, that this macro will allways set `raw` mode, so if
you prefer `canonical` mode you should use `with-open-stream` and
`stty` (see below) instead. There is variant for multiple strams:

`stty` function is like `stty' shell utility:
  (stty fd :b115200 :raw t :hupcl nil)


In theory it should work on all posix platforms supported by iolib.

I run it under sbcl 1.0.31 & 1.0.32 under archlinux and debian lenny,
clisp 2.47 under archlinux and debian lenny, ccl 1.3 and 1.4 under archlinux.
(all 32 bit).


0 Checking right `#+' and `#-' for non posix features.

1 Testing on other OS and lisp implementation.

2 Testing units.

3 Restarts on i/o methods.

4 Streams class and methods for 9-bit mode (using parity checking bits
  for data too).