Re: Working with files on different operating systems

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: Working with files on different operating systems
Date	2015-10-31 21:38 +0000
Organization	A noiseless patient Spider
Message-ID	<87r3ka90rs.fsf@bsb.me.uk> (permalink)
References	(2 earlier) <mv8r8o$ru8$1@speranza.aioe.org> <45fdb118-722c-4c06-97c2-e79bad82dc63@googlegroups.com> <cfcc242d-1e3e-415f-8a6e-a166152029de@googlegroups.com> <87r3kaak4r.fsf@bsb.me.uk> <4b7bb2fa-96c8-48db-a460-d756517f44a4@googlegroups.com>

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supercat@casperkitty.com writes:

> On Saturday, October 31, 2015 at 2:55:10 PM UTC-5, Ben Bacarisse wrote:
>> And then there were bit-field selectors.  I'm sure many people would
>> like to have had them in C.  Still, C is what it is.  Given the bad
>> press, it's surprising how popular it still is!
>
> Tell me more.  What I've long wished for in C would have been a means of
> indicating that ".someIdentifier" should be regarded as an alias for some
> bits taken from other members of the structure.  That would have provided
> all the utility of bitfields, but with a system-independent meaning.

No, it's very different, though it might be applicable in some of the
same situations.  There is a construct

  SLCT len : shift : offset

which, at least conceptually, packs those three values into a word
(everything's a word in BCPL).  The OF operator takes a selector on the
left and evaluates its right hand side to get a pointer, p.  The OF
exporession denotes the 'len' bits 'shift' bits from the right-hand end
of the word at address p + offset.  The main thing of interest is that
OF expressions can be assigned to.

-- 
Ben.

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Thread

Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 05:11 +0200
  Re: Working with files on different operating systems Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-10-08 22:12 -0600
  Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 00:18 -0500
    Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 11:13 +0100
      Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:05 +0200
        Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:49 -0500
        Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 17:32 -0400
        Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-10 12:37 +1300
      Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:48 -0500
        Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 19:53 +0100
          Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:09 +0200
            Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 20:28 +0100
              Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:40 +0200
                Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 15:59 -0400
                Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 22:07 +0200
                Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 16:24 -0400
                Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-10 03:08 +0200
                Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-09 21:50 +0100
        Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 14:54 -0400
          Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:05 +0200
            Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 21:47 +0200
            Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 15:53 -0400
              Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 22:01 +0200
                Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-09 16:05 -0400
          Re: Working with files on different operating systems glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-10 01:16 +0000
            Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-10 03:46 +0200
            Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-10 08:08 -0400
          Re: Working with files on different operating systems raltbos@xs4all.nl (Richard Bos) - 2015-10-10 17:02 +0000
        Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 15:53 -0400
    Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:00 +0200
      Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 12:59 -0500
        Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 12:37 -0700
          Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 17:36 -0500
            Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 16:52 -0700
              Re: Working with files on different operating systems raltbos@xs4all.nl (Richard Bos) - 2015-10-14 11:27 +0000
                Re: Working with files on different operating systems James Kuyper <jameskuyper@verizon.net> - 2015-10-14 11:27 -0400
                Re: Working with files on different operating systems Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-14 16:46 +0000
                Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-14 10:18 -0700
              Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-14 23:06 -0500
    Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 09:16 -0700
      Re: Working with files on different operating systems Les Cargill <lcargill99@comcast.com> - 2015-10-09 17:43 -0500
        Re: Working with files on different operating systems Keith Thompson <kst-u@mib.org> - 2015-10-09 16:57 -0700
          Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-09 22:41 -0700
    Re: Working with files on different operating systems David Thompson <dave.thompson2@verizon.net> - 2015-10-31 06:50 -0400
  Re: Working with files on different operating systems Siri Cruz <chine.bleu@yahoo.com> - 2015-10-08 23:25 -0700
    Re: Working with files on different operating systems Geoff <geoff@invalid.invalid> - 2015-10-10 10:35 -0700
  Re: Working with files on different operating systems Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-09 08:42 -0400
    Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-09 18:51 +0200
      Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-15 18:09 -0700
        Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-17 04:01 +0200
          Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-17 15:55 +1300
            Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-16 20:09 -0700
              Re: Working with files on different operating systems Ian Collins <ian-news@hotmail.com> - 2015-10-17 16:36 +1300
            Re: Working with files on different operating systems "Morten W. Petersen" <morphex@gmail.com> - 2015-10-17 05:10 +0200
        Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 12:05 -0700
          Re: Working with files on different operating systems Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-31 12:42 -0700
            Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 13:40 -0700
          Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-31 19:55 +0000
            Re: Working with files on different operating systems supercat@casperkitty.com - 2015-10-31 13:43 -0700
              Re: Working with files on different operating systems Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-31 21:38 +0000

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