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From: bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: question about nullptr
Date: Sat, 6 Jul 2024 19:20:15 +0100
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On 06/07/2024 15:04, Scott Lurndal wrote:
> Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
>> On 06.07.2024 14:54, Kaz Kylheku wrote:
>>> On 2024-07-06, Thiago Adams <thiago.adams@gmail.com> wrote:
>>>> If you were creating C code today and could use a C23 compiler, would
>>>> you use nullptr instead of NULL?
>>>
>>> In greenfield projects under my dictatorship, I use 0, as in:
>>>
>>>     char *p = 0;
>>>
>>> I was still 20 something when I (easily) wrapped my head around the 0
>>> null pointer constant, and have not had any problems with it.
>>> Once I learned the standard-defined truth about null pointer constants,
>>> and their relationship to the NULL macro, I dropped NULL like a hot
>>> potato, and didn't look back (except when working in code bases that use
>>> NULL).
>>
>> We also used 0 as "universal" pointer value regularly without problems.
> 
> Whereas I spent 6 years programming on an architecture[*] where a
> null pointer was represented in hardware by the value 0xc0eeeeee.  I always
> use the NULL macro in both C and C++ code.


You can ignore that requirement and just use all-bits-zero (in memory, 
not just in C source code). After all, the only thing you might want 
hardware support for is trapping a dereference of a NULL value.

Presumably it was more of an ABI thing where all languages/compilers 
complying with it had to use the same NULL value, so the choice could 
have been made there.