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Re: I want to ask a question...

From glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups comp.lang.c
Subject Re: I want to ask a question...
Date 2015-08-08 05:51 +0000
Organization Aioe.org NNTP Server
Message-ID <mq45cr$hao$1@speranza.aioe.org> (permalink)
References (2 earlier) <lnmvy2g291.fsf@kst-u.example.com> <mq3cqv$7el$1@speranza.aioe.org> <lnio8qfyr7.fsf@kst-u.example.com> <mq3f0j$bgp$1@speranza.aioe.org> <lnegjefsrd.fsf@kst-u.example.com>

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Keith Thompson <kst-u@mib.org> wrote:

(snip on referencing pointers to unallocated memory)
(then I wrote)
>> I presume you are still not allowed to copy them with memcpy(),
>> which you might want to use to copy such an array. You can see
>> that it might be a lot easier (and faster) to memcpy() a whole 
>> array, instead of carefully testing each one.
 
> Yes, you can use mempcy().  memcpy() operates (logically) on character
> values, which have no trap representations.

Interesting loophole in the pointer reference question.
 
> Also, the value of a structure or union object is never a trap
> representation, even if some of its members might be (N1570 6.2.6p6).

I suppose there aren't so many hardware processors that don't allow
such copying of pointers now, but some virtual machines don't like it.

Then do I suppose you can also memcmp() pointers that you couldn't
otherwise compare?

-- glen

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Thread

Re: I want to ask a question... Gareth Owen <gwowen@gmail.com> - 2015-08-07 20:00 +0100
  Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 19:04 +0000
  Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 15:30 -0700
    Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 22:52 +0000
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 16:46 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 23:29 +0000
          Re: I want to ask a question... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-08 01:37 +0100
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 18:55 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-08 05:51 +0000
              Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-08 01:44 -0500
    Re: I want to ask a question... Ken Brody <kenbrody@spamcop.net> - 2015-08-10 12:46 -0400
    Re: I want to ask a question... supercat@casperkitty.com - 2015-08-19 16:43 -0700
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 18:09 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 01:00 +0000
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 20:25 -0700
            Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 08:15 -0700
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 11:38 -0700
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 18:47 +0000
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 14:01 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 16:43 +0000
              Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 13:02 -0400
                Re: I want to ask a question... Tonton Th <tTh@nowhere.invalid> - 2015-08-20 17:40 +0000
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 15:27 -0400
                Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 22:58 +0200
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 23:24 -0400
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-21 06:19 +0000
                Re: I want to ask a question... Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-08-21 09:20 -0600
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:25 -0700
                Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-23 01:33 -0500
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 19:28 +0000
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 12:11 -0700
          Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 10:02 +0200
        Re: I want to ask a question... raltbos@xs4all.nl (Richard Bos) - 2015-08-22 13:42 +0000
          Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:23 -0700

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