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Groups > comp.lang.c++ > #81598

Re: NULL versus 0

From Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups comp.lang.c++
Subject Re: NULL versus 0
Date 2021-09-26 02:15 -0700
Organization None to speak of
Message-ID <87a6jzlmu6.fsf@nosuchdomain.example.com> (permalink)
References <21138a34-469b-4c7a-9ef1-e9307ba52673n@googlegroups.com> <c52e136c-17bb-4eb4-8407-891571d9ef92n@googlegroups.com> <slrnsl06g7.5o3.grahn+nntp@frailea.sa.invalid> <aAV3J.57544$2Q_3.32321@fx35.iad>

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Branimir Maksimovic <branimir.maksimovic@gmail.com> writes:
> On 2021-09-26, Jorgen Grahn <grahn+nntp@snipabacken.se> wrote:
>> On Sat, 2021-09-25, see.my....@gmail.com wrote:
>>>> int *pInt = 0; 
>>>> 
>>>> Nothing inherently wrong with that, but in C, it would be more
>>>> traditional to use NULL.
>>>
>>> It would be more traditional in C++, as well.
>>
>> Opinions varied.  Before nullptr, I always used NULL in C and 0 in
>> C++.  IIRC using 0 was a common recommendation here, too, for whatever
>> reason.
>
> #define NULL (void*)0 
> simple, problem is that in C++, one have to cast from void
> and that does not works, and this is BuG in C++.

That's not a valid definition of NULL in either C or C++.

In C or C++, the definition has to be parenthesized to avoid parsing
errors in some contexts;

    #define NULL ((void*0)

I'm not sure what you mean by "this is BuG in C++".  A C++
implementation that defined NULL that way would be non-conforming.

-- 
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

NULL versus 0 "das...@gmail.com" <dashley@gmail.com> - 2021-09-25 11:03 -0700
  Re: NULL versus 0 Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 18:16 +0000
  Re: NULL versus 0 Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-25 21:20 +0300
    Re: NULL versus 0 Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-25 21:32 +0300
      Re: NULL versus 0 "das...@gmail.com" <dashley@gmail.com> - 2021-09-25 12:08 -0700
    Re: NULL versus 0 Juha Nieminen <nospam@thanks.invalid> - 2021-09-27 05:47 +0000
      Re: NULL versus 0 Bo Persson <bo@bo-persson.se> - 2021-09-27 08:32 +0200
        Re: NULL versus 0 "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-09-26 23:37 -0700
        Re: NULL versus 0 "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-27 10:32 +0200
          Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-27 11:32 -0700
      Re: NULL versus 0 James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-27 15:03 -0400
  Re: NULL versus 0 "see.my....@gmail.com" <see.my.homepage@gmail.com> - 2021-09-25 13:05 -0700
    Re: NULL versus 0 Jorgen Grahn <grahn+nntp@snipabacken.se> - 2021-09-26 06:58 +0000
      Re: NULL versus 0 Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-26 07:47 +0000
        Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-26 02:15 -0700
          Re: NULL versus 0 Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-26 09:38 +0000
            Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-26 15:03 -0700
              Re: NULL versus 0 Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-29 02:29 +0000
                Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-28 20:34 -0700
                Re: NULL versus 0 David Brown <david.brown@hesbynett.no> - 2021-09-29 08:52 +0200
        Re: NULL versus 0 Bo Persson <bo@bo-persson.se> - 2021-09-26 13:54 +0200
          Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-26 15:17 -0700
          Re: NULL versus 0 Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-29 02:26 +0000
      Re: NULL versus 0 Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-26 02:17 -0700
      Re: NULL versus 0 HorseyWorsey@the_stables.com - 2021-09-26 14:20 +0000
  Re: NULL versus 0 James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-25 17:36 -0400
  Re: NULL versus 0 "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-09-26 23:05 -0700

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