Re: Never use strncpy!

From	"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups	comp.lang.c++
Subject	Re: Never use strncpy!
Date	2022-10-03 13:49 -0700
Organization	A noiseless patient Spider
Message-ID	<thfhtg$2ahuv$2@dont-email.me> (permalink)
References	(11 earlier) <IL2ZK.114890$6gz7.16864@fx37.iad> <th8fih$18v7q$1@dont-email.me> <Yn_ZK.97606$chF5.85448@fx08.iad> <837042c7-ced4-4fd6-92c4-8952d2d4ed07n@googlegroups.com> <XWB_K.233427$51Rb.232244@fx45.iad>

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On 10/3/2022 7:01 AM, Scott Lurndal wrote:
> Michael S <already5chosen@yahoo.com> writes:
>> On Saturday, October 1, 2022 at 8:02:05 PM UTC+3, Scott Lurndal wrote:
>>> Bonita Montero <Bonita....@gmail.com> writes:
>>>> Am 28.09.2022 um 23:11 schrieb Scott Lurndal:
>>>>
>>>>> When ARM was designing their 64-bit architecture (ARMv8) circa 2011/2, they
>>>>> only provided a LL/SC equivalent (load-exclusive/store-exclusive). Their
>>>>> architecture partners at the time quickly requested support for
>>>>> real RMW atomics, which were added as part of the LSE (Large System ISA
>>>>> Extensions). LDADD, LDCLR (and with complement), LDSET (or), LDEOR (xor),
>>>>> LDSMAX (signed maximum), LDUMAX (unsigned maximum), LDSMIN, LDUMIN.
>>>>
>>>> Eh, RMW can be emulated with LL/SC but not vice versa.
>>>> A CAS emulated by LL/SC isn't slower than a native CAS.
>>>> But atomic increments, decrements, ands, ors or whatever
>>>> ebulated with LL/SC is sometimes slower.
>>>>
>>> Who said anything about CAS[*]?
>>>
>>>
>>> [*] For your edification, CAS on modern archtitectures isn't
>>> handled by the CPU, but rather by the point of coherency (LLC
>>> or PCI-Express/CXL endpoint).
>>
>> I don't think so.
> 
> The processors that we build implement it exactly as I say.
> 
>> IMHO, a typical implementation is that CPU acquires the ownership
>> of location and refuses all attempts by other agents to take it back
>> until both parts of CAS are completed and committed to L1$.
> 
> That hasn't been my experience (in the past with Intel/AMD x86_64
> where we extended the coherency protocol from HT/QPI over a high
> speed fabric (IB/10Ge), and currently with custom high-end ARM64
> processors that my CPOE sells).
> 
> Note that I said at the "point of coherency".    That may very
> well be the L1 cache for some processors, the L2/LLC for others
> (depending on cache inclusivity etc.).

Correct.

Thread

Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-21 10:04 +0000
  Re: Never use strncpy! "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-09-21 15:06 +0200
  Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-21 15:24 +0200
    Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-21 15:30 +0200
      Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-21 19:20 +0200
        Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-21 19:33 +0200
          Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-21 23:14 +0200
            Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-22 04:40 +0200
              Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-22 08:56 +0200
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-22 12:02 +0200
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-23 13:23 +0200
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-23 13:49 +0200
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-23 15:25 +0200
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-23 16:03 +0200
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-23 14:34 +0000
                Re: Never use strncpy! Michael S <already5chosen@yahoo.com> - 2022-09-23 08:19 -0700
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-23 17:57 +0000
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-23 18:36 +0200
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-24 16:22 +0200
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-24 16:25 +0200
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-24 17:09 +0200
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-24 17:14 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-09-26 17:34 -0700
                Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-26 07:53 +0000
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-26 10:21 +0200
                Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-26 08:34 +0000
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-26 13:39 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-09-26 17:47 -0700
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-27 14:17 +0000
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-27 18:07 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-09-27 12:42 -0700
                Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-28 09:32 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-09-28 13:34 -0700
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-28 21:11 +0000
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-01 06:26 +0200
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-10-01 17:01 +0000
                Re: Never use strncpy! Michael S <already5chosen@yahoo.com> - 2022-10-02 15:32 -0700
                Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-10-03 14:01 +0000
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-03 13:49 -0700
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-02 12:46 -0700
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-03 04:14 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-02 19:43 -0700
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-02 19:48 -0700
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-03 04:53 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-02 19:58 -0700
                Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-10-03 08:27 +0200
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-03 13:49 -0700
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-04 10:53 -0700
                Re: Never use strncpy! "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-02 12:44 -0700
            Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-22 05:59 +0000
              Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-22 09:32 +0200
    Re: Never use strncpy! Muttley@dastardlyhq.com - 2022-09-21 15:42 +0000
      Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-21 18:10 +0200
        Re: Never use strncpy! Muttley@dastardlyhq.com - 2022-09-21 16:19 +0000
          Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-21 18:27 +0200
            Re: Never use strncpy! Muttley@dastardlyhq.com - 2022-09-23 14:47 +0000
      Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-21 16:12 +0000
    Re: Never use strncpy! Philipp Klaus Krause <pkk@spth.de> - 2022-09-23 19:52 +0200
      Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-24 16:25 +0200
  Re: Never use strncpy! scott@slp53.sl.home (Scott Lurndal) - 2022-09-21 14:00 +0000
    Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-22 06:03 +0000
      Re: Never use strncpy! Philipp Klaus Krause <pkk@spth.de> - 2022-09-23 19:50 +0200
        Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-26 07:54 +0000
  Re: Never use strncpy! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-21 15:56 +0100
  Re: Never use strncpy! Muttley@dastardlyhq.com - 2022-09-21 15:36 +0000
  Re: Never use strncpy! Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-09-21 08:59 -0700
  Re: Never use strncpy! Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-09-21 13:23 -0700
    Re: Never use strncpy! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-21 21:49 +0100
      Re: Never use strncpy! Richard Damon <Richard@Damon-Family.org> - 2022-09-21 19:18 -0400
        Re: Never use strncpy! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-22 00:39 +0100
          Re: Never use strncpy! Richard Damon <Richard@Damon-Family.org> - 2022-09-21 20:45 -0400
            Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-21 18:00 -0700
          Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-21 17:55 -0700
        Re: Never use strncpy! Juha Nieminen <nospam@thanks.invalid> - 2022-09-22 06:09 +0000
          Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-22 11:44 -0700
          Re: Never use strncpy! Richard Damon <Richard@Damon-Family.org> - 2022-09-22 23:33 -0400
      Re: Never use strncpy! Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-09-22 19:00 -0700
        Re: Never use strncpy! Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-09-22 19:04 -0700
          Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-22 22:49 -0700
    Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-24 11:38 +0200
      Re: Never use strncpy! Muttley@dastardlyhq.com - 2022-09-24 09:43 +0000
        Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-24 11:59 +0200
      Re: Never use strncpy! Richard Damon <Richard@Damon-Family.org> - 2022-09-24 06:27 -0400
        Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-24 11:53 -0700
          Re: Never use strncpy! Bonita Montero <Bonita.Montero@gmail.com> - 2022-09-24 20:58 +0200
  Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-21 16:01 -0700
    Re: Never use strncpy! David Brown <david.brown@hesbynett.no> - 2022-09-22 09:37 +0200
    Re: Never use strncpy! Manfred <noname@add.invalid> - 2022-10-01 01:24 +0200
      Re: Never use strncpy! Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-30 16:43 -0700
  Re: Never use strncpy! Lynn McGuire <lynnmcguire5@gmail.com> - 2022-09-22 21:03 -0500

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