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Re: OT: One of Anton's papers makes Hacker News

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From Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm>
Newsgroups comp.lang.forth
Subject Re: OT: One of Anton's papers makes Hacker News
Date Sat, 5 Mar 2016 19:43:09 -0500
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On Sat, 5 Mar 2016 13:51:44 -0000 (UTC)
Bernd Paysan <bernd.paysan@gmx.de> wrote:

> Am Fri, 04 Mar 2016 21:01:45 -0500 schrieb Rod Pemberton:

> > char a[10];
> > 
> >  memmove(a[2],a[5],5);
> > 
> > a[2] and a[5] "reduce" to pointers to char.  
> 
> No, to char.  a[2] is accessing the array.
> 
> > These pointers to char are converted to pointers to void to be
> > passed into memmove().
> > All type information is lost at that point.  
> 
> But not the segment information, if in a segmented architecture.
> 
> > It does not propagate as you've indicated in your article.  In
> > memmove(), there is no type association, no object association, etc
> > for dest and src.  
> 
> Ouch.  You are really not a C expert, as you pass two chars to
> memmove, instead of two char*, as it would be with
>   memmove(a+2, a+5, 5);
> 

Late night.  Simple typo:

 memmove(&a[2],&a[5],5);

> On the other hand, you also don't understand segmented memory,
> probably because you are too young to have programmed in DOS or
> worse, 16 bit Windows, with the far pointer model.

(Ok, here we go again with Bernd violating German law again which
prohibits German citizens from engaging in any hate speech, speech
which incites, or insults.  We have free speech.  You don't.)

I started programming in 1981.  I fully understand DOS segmented
memory, as DOS is the primary platform for my personal C code
for the last decade or so.

> A pointer comparison there was only an offset comparison,

A pointer comparison is only an offset comparison for any x86 mode,
be it 16-bit RM, 16-bit PM, 32-bit PM, or 64-bit PM.  There are no
absolute addresses in the x86 architecture.  It's entirely
segmented.  16-bit RM used segment and offset, and PM uses a base
address plus an offset.  What's your point?

> In your case, memmove has two pointers pointing to the same object.

No.  They no longer point to an object once converted to "void *" to
be passed into memmove().  They are pointers to nothing, i.e., "void".
Once in memmove(), they're just a pointer in C terminology, which
is usually mapped to a memory address for most implementations.

> If you do a memmove(a+2, b+5, 5), you would have two different
> objects, likely with two different segments and the offsets 2 and 5.

No.  No objects are involved once 'a+2' or 'b+5', presumed to be
pointers to char, "char *", when memmover() is called, are converted
to pointers to void, "void *" to pass them as parameters.  How do
you expect a memory function, memmove, to work with objects?  ...
They work on memory.

> The thing missing from the C standard is a description why
> something marked UB is an UB.

Why?  C allows for implementation defined behavior.  In fact,
you couldn't use C for much without defining UB to do something
meaningful for each platform.  E.g., conversion of pointers to
various types, conversion of integers to pointers, etc.

> You
> don't even understand that there can be different objects in C.

Not true, but neither you nor Anton seem to understand that ANSI C
standard introduced the concept of a non-object.  Prior to ANSI C,
all C objects had both data and an address, although historically
pointers to char were used as pointers to void.


None of this changes my point that Anton has a bad example
for something he didn't or doesn't understand in a formal
paper.


Rod Pemberton

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Thread

OT: One of Anton's papers makes Hacker News Paul Rubin <no.email@nospam.invalid> - 2016-03-03 16:24 -0800
  Re: OT: One of Anton's papers makes Hacker News Julian Fondren <julian.fondren@gmail.com> - 2016-03-03 21:06 -0800
    Re: OT: One of Anton's papers makes Hacker News Ron Aaron <rambamist@gmail.com> - 2016-03-04 07:18 +0200
    Re: OT: One of Anton's papers makes Hacker News Paul Rubin <no.email@nospam.invalid> - 2016-03-03 21:33 -0800
      Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-04 17:52 +0000
    Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-04 12:32 +0000
      Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-04 18:20 +0000
        Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-05 02:23 +0000
          Re: OT: One of Anton's papers makes Hacker News hughaguilar96@gmail.com - 2016-03-04 19:06 -0800
            Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-05 20:32 -0500
          Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 11:28 +0000
            Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-06 18:02 +0000
              Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-06 23:55 +0000
            Re: OT: One of Anton's papers makes Hacker News hughaguilar96@gmail.com - 2016-03-06 14:48 -0800
              Re: OT: One of Anton's papers makes Hacker News Julian Fondren <julian.fondren@gmail.com> - 2016-03-07 03:36 -0800
            Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-07 19:19 -0500
              Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 17:40 +0000
        Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-05 03:35 -0600
          Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-05 13:37 +0000
            Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-05 15:42 -0600
              Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-06 00:50 +0000
                Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-05 20:33 -0500
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-06 02:01 +0000
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-06 11:57 +0000
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-07 07:35 +0000
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-07 12:40 +0000
                Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-07 19:20 -0500
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-08 00:49 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-06 02:20 -0600
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-07 00:35 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-07 02:53 -0600
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-07 16:07 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-08 05:17 -0600
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-08 22:01 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-09 03:14 -0600
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-09 11:17 +0000
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-09 23:58 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-10 04:45 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-10 11:39 +0000
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-10 13:29 +0000
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 16:02 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-10 08:22 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 15:49 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-12 13:35 -0600
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-10 21:58 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-11 06:11 -0600
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-12 00:05 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-12 04:23 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 12:05 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-12 08:36 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 16:57 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-12 13:44 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 14:29 +0000
                Re: OT: One of Anton's papers makes Hacker News "Elizabeth D. Rather" <erather@forth.com> - 2016-03-11 15:02 -1000
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 16:20 +0000
                Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-12 13:53 -0600
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 13:02 +0000
          Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 11:52 +0000
            Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-06 12:42 -0600
              Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-06 13:12 -0600
  Re: OT: One of Anton's papers makes Hacker News Ron Aaron <rambamist@gmail.com> - 2016-03-04 07:20 +0200
  Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-04 17:37 +0000
  Re: OT: One of Anton's papers makes Hacker News Julian Fondren <julian.fondren@gmail.com> - 2016-03-04 11:23 -0800
    Re: OT: One of Anton's papers makes Hacker News Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-09 03:24 -0600
  Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-04 21:01 -0500
    Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-05 13:51 +0000
      Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-05 19:43 -0500
        Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-06 01:45 +0000
          Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-07 19:19 -0500
            Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 17:24 +0000
              Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-13 12:27 +0000
                Re: OT: One of Anton's papers makes Hacker News raltbos@xs4all.nl (Richard Bos) - 2016-03-13 13:50 +0000
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-13 19:52 +0000
                Re: OT: One of Anton's papers makes Hacker News Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-03-13 16:08 -0400
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-13 13:40 -0700
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-14 00:41 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-13 18:23 -0700
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-14 02:59 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-13 20:29 -0700
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-14 22:44 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-14 16:23 -0700
                Re: OT: One of Anton's papers makes Hacker News Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-03-14 23:55 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-14 17:19 -0700
                Re: OT: One of Anton's papers makes Hacker News Robert Wessel <robertwessel2@yahoo.com> - 2016-03-14 19:26 -0500
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-15 00:48 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-14 22:30 -0700
                Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-15 07:23 +0000
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-15 10:09 +0000
                Re: OT: One of Anton's papers makes Hacker News Keith Thompson <kst-u@mib.org> - 2016-03-15 08:56 -0700
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-15 19:33 +0000
                Re: OT: One of Anton's papers makes Hacker News Rosario19 <Ros@invalid.invalid> - 2016-03-17 09:46 +0100
                Re: OT: One of Anton's papers makes Hacker News Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-17 09:37 -0400
                Re: OT: One of Anton's papers makes Hacker News Rosario19 <Ros@invalid.invalid> - 2016-03-17 18:40 +0100
                Re: OT: One of Anton's papers makes Hacker News Jerry Stuckle <jstucklex@attglobal.net> - 2016-03-17 13:53 -0400
                Re: OT: One of Anton's papers makes Hacker News invalid <address@is.invalid> - 2016-03-17 18:00 +0000
                Re: OT: One of Anton's papers makes Hacker News Rosario19 <Ros@invalid.invalid> - 2016-03-17 18:37 +0100
                Re: OT: One of Anton's papers makes Hacker News Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-18 14:36 +0000
                Re: OT: One of Anton's papers makes Hacker News David Brown <david.brown@hesbynett.no> - 2016-03-14 09:17 +0100
                Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-14 22:56 +0000
                Re: OT: One of Anton's papers makes Hacker News Robert Wessel <robertwessel2@yahoo.com> - 2016-03-14 20:00 -0500
                Re: OT: One of Anton's papers makes Hacker News David Brown <david.brown@hesbynett.no> - 2016-03-15 11:22 +0100
                Re: OT: One of Anton's papers makes Hacker News raltbos@xs4all.nl (Richard Bos) - 2016-03-14 22:38 +0000
                Re: OT: One of Anton's papers makes Hacker News Randy Howard <rhoward.mx@EverybodyUsesIt.com> - 2016-03-14 01:40 -0500
    Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 11:00 +0000
      Re: OT: One of Anton's papers makes Hacker News Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-07 19:19 -0500
        Re: OT: One of Anton's papers makes Hacker News Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-08 01:02 +0000
  Re: OT: One of Anton's papers makes Hacker News Julian Fondren <ayrnieu@gmail.com> - 2016-03-14 07:29 -0700
    Re: OT: One of Anton's papers makes Hacker News anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-18 17:45 +0000

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