linux-kernel - Re: [PATCH 12/24] getgrent_r.3: Use sizeof() to get buffer size (instead of hardcoding macro name)

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Date:   Tue, 29 Sep 2020 15:57:22 +0200
From:   Alejandro Colomar <colomar.6.4.3@...il.com>
To:     mtk.manpages@...il.com
Cc:     Stefan Puiu <stefan.puiu@...il.com>,
        lnx-man <linux-man@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 12/24] getgrent_r.3: Use sizeof() to get buffer size
 (instead of hardcoding macro name)



On 2020-09-29 15:38, Michael Kerrisk (man-pages) wrote:
>> 2.-     Use sizeof() everywhere, and the macro for the initializer.
>>
>> pros:
>> - It is valid as long as the buffer is an array.
>> cons:
>> - If the code gets into a function, and the buffer is then a pointer,
>>     it will definitively produce a silent bug.
> 
> Sigh! I just did exactly the last point in a test program I've been writing...
> 
> M
> 


Hmmm, maybe you would like to comment on this LKML thread I started 
yesterday:

https://lore.kernel.org/lkml/71c25cb0-9fa2-4e97-c93c-44eadfd781fb@gmail.com

Concretely, point 4 is about this.

I'd push 'array_bytes()' to all "libc"s I can, so that it's then common 
enough to use it everywhere, even in the man.

I'd also recommend reading this StackOverflow answer I wrote last year:

https://stackoverflow.com/a/57537491/6872717


Cheers,

Alex