Re: question about nullptr

scott@slp53.sl.home (Scott Lurndal) writes:

Ben Bacarisse <ben@bsb.me.uk> writes:

scott@slp53.sl.home (Scott Lurndal) writes:
>

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.

>
I also like to use 0, but I'm not sure I could say exactly why.  Maybe
because of pre-C exposure (B and BCPL).
>

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.

>
I'm sure you know (but maybe some other readers might not) that that
does not stop one using 0 in C source code.  Whatever a null pointer
"really" is on some hardware, 0 must work in C, including in comparisons
with == and !=.  You can have

>
Yes.  However, I consider that ambiguous, I prefer to be explicit and
use NULL or nullptr.

In what sense is using 0 ambiguous?  I can't see it.

Ambiguous and explicit are not opposites, so many you did not mean to
say that 0 is ambiguous.  Its use does require the reader to know the
role played by zero integer constant expressions in C.

But then NULL might be defined to be 0.  It /looks/ more like a pointer
but there's lots of code that erroneously assumes that it is, presumably
because of that deceptive look.  (nullptr is another matter.)

Do you always cast NULL to a pointer in those (admittedly rare) cases
when one needs to?  I think it's easier to remember to do that with 0.

--
Ben.