Re: question about nullptr

On 7/9/2024 12:02 AM, Richard Harnden wrote:

On 09/07/2024 07:17, Chris M. Thomasson wrote:

On 7/8/2024 10:42 PM, Richard Harnden wrote:

On 06/07/2024 17:57, David Brown wrote:

On 06/07/2024 16:39, Richard Damon wrote:

On 7/6/24 7:49 AM, Thiago Adams wrote:

If you were creating C code today and could use a C23 compiler, would you use nullptr instead of NULL?
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I am asking because I think I will keep using NULL.
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I like nullptr semantics but I don't like to introduce new element (nullptr) inside the code with no guarantee that the code will not mix both.
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In the past we also didn't have a guarantee we are not mixing 0 or NULL.
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I think the best scenario for a team guideline would be a style warning if 0 or nullptr is used and NULL to be defined as nullptr in a C23 compiler.
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The (small) problem with 0 or NULL being use is that in a context where you THINK you are passing a pointer, but the function actually is taking an integer value, 0 or NULL (defined as a 0) passes the syntax check.
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If C23 REQURIED NULL to be defined as nullptr, then NULL would have been used, but as far as I know, it is still allowed to be defined as 0 (unless you also have POSIX compatibility).
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With POSIX Compatibility, where NULL must have the type of (void*) you also avoid the possible error, and thus the desire to use nullptr.

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I hope that defining NULL as nullptr will become common - but I would be surprised to ever see it being required by C standards.
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The ideal would be for C libraries to define NULL as nullptr and for C compilers to support a flag like gcc's "-Wzero-as-null-pointer-constant" warning (it is currently C++ only). Then people can easily eliminate
any mixup between integer 0 and null pointer constants by using that flag and either NULL or nullptr, according to taste.  (And those who don't want such checks, are not required to change.)
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So, if malloc was changed to 'returns nullptr and sets errno on error', will you still be able to say:
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if ( p == NULL ) ...
if ( !p ) ...
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?

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This of a pointer p where:
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p = 0;

 No, I mean when p = nullptr
 

p = nullptr;
(0 == p == nullptr == NULL == 0) == true ?
Am I missing something here? If so, here is a preemptive: Shit!