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Re: To C or not to C++

From Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups comp.lang.c++
Subject Re: To C or not to C++
Date 2022-08-16 12:56 -0700
Organization None to speak of
Message-ID <87h72cc67o.fsf@nosuchdomain.example.com> (permalink)
References (9 earlier) <tdcobl$129p$1@gioia.aioe.org> <tde56t$1jr6$1@gioia.aioe.org> <jlvo7lF3u0kU1@mid.individual.net> <tdfeji$91u$1@dont-email.me> <tdgqk2$17pq$1@gioia.aioe.org>

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Muttley@dastardlyhq.com writes:
> On Tue, 16 Aug 2022 08:48:18 +0200
> David Brown <david.brown@hesbynett.no> wrote:
>>On 15/08/2022 22:22, Bo Persson wrote:
>>> On 2022-08-15 at 21:01, Muttley@dastardlyhq.com wrote:
>>>> On Mon, 15 Aug 2022 06:16:23 -0000 (UTC)
>>>> Juha Nieminen <nospam@thanks.invalid> wrote:
>>>>> Muttley@dastardlyhq.com wrote:
>>>>>> Rubbish. I've got multi thousand line originally C programs which I've
>>>>> happily
>>>>>> compiled with C++ compilers in C++ mode due to a few minor C++ 
>>>>>> additions.
>>>>>
>>>>> I assume it's C89. Modern C is more unlikely to be compilable as C++ 
>>>>> as-is
>>>>> (for example because of out-of-order designated initializers, 
>>>>> 'restrict',
>>>>> and so on). Even some completely standard-legal C89 won't compile as 
>>>>> C++,
>>>>> such as:
>>>>>
>>>>>   char *str = "hello";
>>>>>
>>>>> (which is 100% valid standard C, but not valid C++.)
>>>>
>>>> Both clang and gcc will compile it but with a warning.
>>>>
>>> 
>>> And the warning says that it *is* valid?!
>>
>>No, the warning tells you that it is /invalid/ :
>>
>>	warning: ISO C++ forbids converting a string constant to 'char*'
>>	[-Wwrite-strings]
>>
>>Muttley must have forgotten to mention that.
>
> I didn't forget anything. The fact is both those compilers will compile it.
> A warning is a warning, its not an error.

As you probably already know, the standard does not require a conforming
compiler to reject anything unless there's a #error directive that
survives preprocessing.  (At least that's the rule for C; I haven't
found wording in the C++ standard that requires rejecting a program with
a #error directive.)  For any other violation of the language rules, all
the standard requires is a diagnostic, which can be a non-fatal warning.

You're right, it's not correct to say that `char *str = "hello";` "won't
compile as C++".  A conforming compiler must diagnose it, but after
doing so it may either accept it or reject it.  The warning quoted above
satisifies the standard's requirement for a diagnostic.

A C++ program containing that declaration is *ill-formed*.

The distinction between a warning and an error is less significant than
you imply it is.

I'd say the content of the warning was relevant.  You chose to omit it
for some reason.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

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Thread

To C or not to C++ NOSPAM.Alan.Beck@darkrealms.ca (Alan Beck) - 2022-08-08 09:43 +0000
  Re: To C or not to C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-08 20:02 +0300
  Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-09 05:38 +0000
    Re: To C or not to C++ Ralf Fassel <ralfixx@gmx.de> - 2022-08-09 11:07 +0200
      Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-10 02:25 +0200
        Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-09 17:52 -0700
          Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-09 21:39 -0700
            Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-10 07:45 +0000
          Re: To C or not to C++ scott@slp53.sl.home (Scott Lurndal) - 2022-08-10 19:50 +0000
            Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-10 13:13 -0700
            Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-11 04:29 +0200
        Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-10 02:41 +0000
        Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-10 07:39 +0000
          Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-10 10:11 -0700
            Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-12 08:23 +0000
              Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-12 12:12 +0000
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-12 14:41 +0000
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-12 12:09 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-13 10:28 +0200
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-13 09:37 +0000
              Re: To C or not to C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-12 15:55 +0300
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-12 14:43 +0000
                Re: To C or not to C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-12 18:07 +0300
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-12 15:14 +0000
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-12 12:11 -0700
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-13 09:38 +0000
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-13 17:56 +0200
                Re: To C or not to C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-24 11:32 +0300
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 11:33 +0100
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-24 04:37 -0700
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 13:31 +0100
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-24 14:09 +0000
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 15:31 +0100
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-24 14:38 +0000
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 15:57 +0100
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-24 10:41 -0700
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 21:48 +0100
                Re: To C or not to C++ "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-08-25 07:34 +0200
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-25 11:29 +0100
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-25 04:14 -0700
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-25 12:36 +0100
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-25 05:16 -0700
                Re: To C or not to C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-25 17:16 +0100
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-25 20:35 +0200
                [OT] Bad CS course, no cookie (Was: To C or not to C++) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-25 21:32 +0100
                Re: [OT] Bad CS course, no cookie (Was: To C or not to C++) David Brown <david.brown@hesbynett.no> - 2022-08-25 23:16 +0200
                Re: [OT] Bad CS course, no cookie Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-26 00:33 +0100
                Re: [OT] Bad CS course, no cookie David Brown <david.brown@hesbynett.no> - 2022-08-26 10:39 +0200
                Re: [OT] Bad CS course, no cookie Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-26 10:57 +0100
                Re: [OT] Bad CS course, no cookie David Brown <david.brown@hesbynett.no> - 2022-08-26 12:49 +0200
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-25 19:56 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-26 10:47 +0200
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-26 02:48 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-26 13:02 +0200
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-26 04:57 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-26 14:55 +0200
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-26 06:20 -0700
                Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-27 18:44 +0200
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-28 11:30 +0200
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-25 10:06 -0700
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-25 10:32 -0700
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-25 11:36 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-25 20:47 +0200
                Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-26 03:11 +0200
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-25 09:21 +0200
                Re: To C or not to C++ scott@slp53.sl.home (Scott Lurndal) - 2022-08-25 12:58 +0000
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-25 10:23 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-25 20:51 +0200
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-25 12:14 -0700
                Re: To C or not to C++ scott@slp53.sl.home (Scott Lurndal) - 2022-08-24 13:56 +0000
                Re: To C or not to C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-24 17:18 +0300
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-24 14:25 +0000
                Re: To C or not to C++ scott@slp53.sl.home (Scott Lurndal) - 2022-08-12 16:46 +0000
                Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-15 06:16 +0000
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-15 19:01 +0000
                Re: To C or not to C++ Bo Persson <bo@bo-persson.se> - 2022-08-15 22:22 +0200
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-16 08:48 +0200
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-16 19:19 +0000
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-16 12:56 -0700
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-17 18:47 +0000
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-17 14:49 -0700
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-18 14:49 +0000
                Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-19 03:10 +0200
                Re: To C or not to C++ d thiebaud <thiebauddick2@aol.com> - 2022-08-18 22:12 -0400
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-18 20:08 -0700
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-19 10:39 +0000
                Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-17 06:45 +0000
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-17 18:48 +0000
                Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-16 19:16 +0000
              Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-12 12:03 -0700
        Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-10 10:13 +0200
          Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-11 04:25 +0200
            Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-11 01:03 -0700
            Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-11 08:11 +0000
            Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-11 13:53 +0200
              Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-13 04:13 +0200
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-13 21:13 +0200
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-13 12:29 -0700
                Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-13 13:12 -0700
                Re: To C or not to C++ David Brown <david.brown@hesbynett.no> - 2022-08-14 00:44 +0200
            Re: To C or not to C++ Öö Tiib <ootiib@hot.ee> - 2022-08-12 02:54 -0700
              Re: To C or not to C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-12 12:12 -0700
                Re: To C or not to C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-12 16:22 -0700
                Re: To C or not to C++ Öö Tiib <ootiib@hot.ee> - 2022-08-12 17:49 -0700
                Re: To C or not to C++ Manfred <noname@add.invalid> - 2022-08-13 03:16 +0200
                Re: To C or not to C++ Öö Tiib <ootiib@hot.ee> - 2022-08-13 09:08 -0700
                Re: To C or not to C++ Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-15 14:44 -0700
        Re: To C or not to C++ Ralf Fassel <ralfixx@gmx.de> - 2022-08-10 12:06 +0200
        Re: To C or not to C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-11 07:04 +0000
  Re: To C or not to C++ Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-09 12:31 +0200
    Re: To C or not to C++ Muttley@dastardlyhq.com - 2022-08-09 15:59 +0000
    Re: To C or not to C++ Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-08-19 04:09 -0700
  Re: To C or not to C++ "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-08-13 12:17 -0700
  Re: To C or not to C++ "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-08-27 23:15 -0700

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