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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: C23 thoughts and opinions
Date: Wed, 22 May 2024 15:53:41 -0700
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David Brown <david.brown@hesbynett.no> writes:
> On 22/05/2024 19:42, Thiago Adams wrote:
[...]
>>   - nullptr
>
> I am fond of nullptr in C++, and will use it in C.  Like most of the
> C23 changes, it's not a big issue - after all, you get a lot of the
> same effect with "#define nullptr (void*)(0)" or similar.  But it
> means your code has a visual distinction between the integer 0 and a
> null pointer, and also lets the compiler or other static checking
> system check better than using NULL would.  (And I don't like NULL - I
> dislike all-caps identifiers in general.)

Quibble: That should be

    #define nullptr ((void*)0)

For example, this doesn't produce a syntax error for `sizeof nullptr`.

Better:

    #if __STDC_VERSION__ < 202311L
    #define nullptr ((void*)0)
    #endif

C23's nullptr is of type nullptr_t, not void*.  But you'd probably have
to go out of your way for that to be an issue (e.g., using nullptr in a
generic selection).

[...]

>>   - constexpr
>
> I will definitely use that.  Sometimes I want a constant expression
> for things like array sizes or static initialisers, and want to
> calculate it.  constexpr gives you that without having to resort to
> macros.  (I'd perhaps be even happier if I could just use const, as I
> can in C++.)

But const doesn't mean constant.  It means read-only.
`const int r = rand();` is perfectly valid.

I dislike the C++ hack of making N a constant expression given
`const int N = 42;`; constexpr made that unnecessary.  C23 makes the
same (IMHO) mistake.

If I had a time machine, I'd spell "const" as "readonly" and make
"const" mean what "constexpr" now means (evaluated at compile time).

[...]

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */