Re: terminal designed for C

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: terminal designed for C
Date	2012-10-24 11:55 -0700
Organization	None to speak of
Message-ID	<lnehknvgxc.fsf@nuthaus.mib.org> (permalink)
References	<90bcf5bb-f8e9-4ea2-9cbe-82110bfd059c@googlegroups.com>

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kerravon <kerravon@w3.to> writes:
> According to the 1990 C standard (which is what I wish to code to),
> there is no "escape" character. So the only way to produce an escape
> character is to harcode its ASCII or EBCDIC value (x'1b'/x'27'
> respectively). I don't like doing that. I want to be able to write an
> editor like micro-emacs without having to have an #ifdef EBCDIC.
[...]

One of C's greatest strengths it the ability to use it to write
*non-portable* code.

If you need to use the ASCII Escape character, just write:

    #define ESCAPE '\x1b'

If you need the EBCDIC Escape character (assuming that it's actually
useful, and that EBCDIC defines it usefully):

    #define EBCDIC_ESCAPE '\x27'

If you need one or the other, depending on the environment, this might
work:

    #if '0' == 48
    #define ESCAPE '\x1b' /* ASCII */
    #else
    #define ESCAPE '\x27' /* EBCDIC */
    #endif

except that, according to N1370 6.10.1p4:

    Whether the numeric value for these character constants matches
    the value obtained when an identical character constant occurs
    in an expression (other than within a #if or #elif directive)
    is implementation-defined.

If it works for the compiler(s) you're using, that's probably good
enough.  If not, you'll need to find some other way to determine whether
the target uses ASCII or EBCDIC.

>                I don't like doing that. I want to be able to write an
> editor like micro-emacs without having to have an #ifdef EBCDIC.

My advice: grit your teeth and write "#ifdef EBCDIC".  Portable code is
good, all else being equal -- but in this case all else is not equal.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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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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