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From: David Brown <david.brown@hesbynett.no>
Newsgroups: comp.lang.c
Subject: Re: Results of survey re. a new array size operator
Date: Wed, 29 Jan 2025 18:01:00 +0100
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On 29/01/2025 17:00, Ben Bacarisse wrote:
> Alexis <flexibeast@gmail.com> writes:
> 
>> JeanHeyd Meneide, a Project Editor for WG14, has just posted the results
>> of a survey re. the preferred form of a new array size operator:
>>
>> -- https://thephd.dev/the-big-array-size-survey-for-c-results
> 
> Curious.  The top objection to the usual macro solution is given as:
> 
>    * double-evaluation of e.g. getting the size of the 1-d part of a 2-d
>      array int meow[3][4]; /* ... */ SIZE_KEYWORD(meow[first_idx()]);
> 
> Does the author not know that there is no evaluation of the operands of
> sizeof in this example?
> 

6.5.3.4p2 :

"""
If the type of the operand is a variable length array type, the operand 
is evaluated; otherwise, the operand is not evaluated and the result is 
an integer constant.
"""

I don't know if that is the source of the double-evaluation concern 
here, but it is certainly a situation in which sizeof /does/ evaluate 
its operand.

> His "About" pages says "Project Editor for ISO/IEC JTC1 SC22 WG14 -
> Programming Languages, C".
>