Re: terminal designed for C

From	Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups	comp.lang.c
Subject	Re: terminal designed for C
Date	2012-10-24 14:15 -0400
Organization	A noiseless patient Spider
Message-ID	<k69b78$etp$1@dont-email.me> (permalink)
References	(1 earlier) <XnsA0F5AAF4B251Asjoukeburrysoesterbe@213.75.12.10> <lnehkpdkc1.fsf@nuthaus.mib.org> <c73cf9be-fc1f-4147-9a65-c2bba81d6b8d@googlegroups.com> <k67cp7$ii$1@dont-email.me> <11d96836-1882-4aa1-8ae2-058752a41328@googlegroups.com>

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On 10/24/2012 5:59 AM, kerravon wrote:
> On Wednesday, October 24, 2012 11:29:28 AM UTC+11, Eric Sosman wrote:
>
> A truly great response - thanks Eric!
>
>> 	"The C89 Committee considered proposals to add the character
>> 	constant '\e' to represent the ASCII ESC ('\033') character.
>> 	This proposal was based upon the use of ESC as the initial
>> 	character of most control sequences in common terminal driving
>> 	disciplines such as ANSI X3.64. However, this usage has no
>
> The exact situation I face.
>
>> 	obvious counterpart in other popular character codes such as
>> 	EBCDIC."
>
>> of this.  I do not know their reasons for declaring that EBCDIC/ESC
>> was not an "obvious counterpart" for ASCII/ESC -- but then, I'm not
>> a character-set expert.  On the evidence at hand, neither are you.
>
> I am using as reference the IBM S/370 reference summary
> 4th edition dated November 1976 (ie more than a decade
> before C90).
>
> It has an ESC at position x'27'.
>
> I have never seen an EBCDIC ESC used for anything though.

     Perhaps that's why the C89 Committee didn't deem EBCDIC/ESC
an "obvious counterpart" to ASCII/ESC: The fact that two control
codes have the same three-letter name doesn't mean they have
similar or even comparable significance.  An EBCDIC table on
Wikipedia lists 001B as the "Unicode equivalent" of EBCDIC ESC,
meaning that whoever prepared the table thought there was a
correspondence, but perhaps the C89 Committee deemed Wikipedia
an insufficiently authoritative source.  (At the time, they
probably also considered Wikipedia too new to be trusted. :)

> I wonder what it all means?

     One thing I think it means is that if you want to drive
X3.64 terminals from EBCDIC-based systems, you'd better find
out from those systems' experts how it's done.  It's possible
that system software would notice \x27 being written and say
"Hey, that's an EBCDIC ESC, and I happen to know it's going to
an X3.64 device that expects ASCII ESC; I'll send \x1B instead."
But it seems more likely that the system would provide some
kind of curses-like facility, allowing the application to be
mostly unaware of the type of terminal hardware in use.  The
abstract model presented by such a library (assuming it exists)
would be a candidate for your "terminal designed for C."

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

Thread

terminal designed for C kerravon <kerravon@w3.to> - 2012-10-22 21:19 -0700
  Re: terminal designed for C Robert Wessel <robertwessel2@yahoo.com> - 2012-10-22 23:34 -0500
    Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-22 21:56 -0700
  Re: terminal designed for C Sjouke Burry <s@b> - 2012-10-23 14:42 +0000
    Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-23 13:06 -0700
      Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-23 15:46 -0700
        Re: terminal designed for C Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-23 20:29 -0400
          Re: terminal designed for C Lew Pitcher <lpitcher@teksavvy.com> - 2012-10-23 21:26 -0400
          Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-24 02:59 -0700
            Re: terminal designed for C Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-24 14:15 -0400
            Re: terminal designed for C Lew Pitcher <lpitcher@teksavvy.com> - 2012-10-24 17:23 -0400
  Re: terminal designed for C Lew Pitcher <lpitcher@teksavvy.com> - 2012-10-23 18:55 -0400
    Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-23 19:56 -0700
    Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-24 16:10 -0700
      Re: terminal designed for C Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-24 20:15 -0400
      Re: terminal designed for C Lew Pitcher <lpitcher@teksavvy.com> - 2012-10-24 21:13 -0400
        Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-24 21:09 -0700
          Re: terminal designed for C "BartC" <bc@freeuk.com> - 2012-10-25 11:29 +0100
            Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-25 03:51 -0700
          Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-10-25 08:49 -0400
          Re: terminal designed for C Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-25 09:04 -0400
            Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-25 14:11 -0700
              Re: terminal designed for C Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-25 17:29 -0400
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 03:33 -0700
                Re: terminal designed for C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-26 12:35 +0100
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 15:46 -0700
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-26 17:11 -0700
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 17:27 -0700
                Re: terminal designed for C Ian Collins <ian-news@hotmail.com> - 2012-10-27 13:39 +1300
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 18:30 -0700
                Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-10-26 22:50 -0400
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-27 01:42 -0700
                Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-10-27 19:18 -0400
                Re: terminal designed for C Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 10:48 -0800
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-12-17 12:27 -0800
                Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-12-17 15:51 -0500
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-12-17 13:35 -0800
                Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-12-17 16:48 -0500
                Re: terminal designed for C Robert Wessel <robertwessel2@yahoo.com> - 2012-12-17 14:53 -0600
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-12-17 13:20 -0800
                Re: terminal designed for C Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-20 10:19 -0800
                Re: terminal designed for C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-27 02:35 +0100
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 18:58 -0700
                Re: terminal designed for C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-27 05:01 +0100
                Re: terminal designed for C Robert Wessel <robertwessel2@yahoo.com> - 2012-10-27 00:56 -0500
                Re: terminal designed for C James Kuyper <jameskuyper@verizon.net> - 2012-10-26 09:03 -0400
                Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-26 11:13 -0700
                Re: terminal designed for C kerravon <kerravon@w3.to> - 2012-10-26 15:15 -0700
            Re: terminal designed for C lawrence.jones@siemens.com - 2012-11-12 18:08 -0500
  Re: terminal designed for C falk@rahul.net (Edward A. Falk) - 2012-10-24 17:29 +0000
  Re: terminal designed for C Keith Thompson <kst-u@mib.org> - 2012-10-24 11:55 -0700

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