Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sources.redhat.com/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com
Reply-To:	zeil AT cs DOT odu DOT edu
Subject:	Re: how do i simulate a null character from the keyboard?
To:	cygwin AT cygwin DOT com
Cc:	emallove AT yahoo DOT com
X-Mailer:	Lotus Notes Release 5.0.2b December 16, 1999
Message-ID:	<OFDDF8933A.F444C8BE-ON85256B67.0062B0FE@cs.odu.edu>
From:	szeil AT notesmail DOT cs DOT odu DOT edu
Date:	Thu, 21 Feb 2002 13:08:13 -0500
X-MIMETrack:	Serialize by Router on lotus/ODUCS(Release 5.0.8 |June 18, 2001) at 02/21/2002
	01:08:14 PM
MIME-Version:	1.0

Ethan Mallove <emallove at yahoo dot com> wrote:
>
>  why is ctrl-d a logout command
>instead of NULL?
>
Because that's what ctrl-d is supposed to be for!

In the ASCII character code set, ctrl-d is defined as the EOT
signal, short for "End Of Transmission".  So Unix (and
consequently Cygwin) were just following the published
standard.

NUL would, in general, be a terrible choice for an OS to
adopt because NUL characters have perfectly useful
applications in serial data streams (e.g., as something
that you can insert into a stream to affect the timing
without altering the message).

ctrl-z, by the way, used as the terminator by MSDOS and other
early PC operating systems was an unintentionally humorous
choice. It's defined as the SUB character, used as
a placeholder to indicate the data lost during a garbled transmission.

Steve Z



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

- Raw text -