[PATCH] Declare reallocarray by default

[Florian Weimer]

On 08/29/2018 01:14 AM, Carlos O'Donell wrote:
> On 08/28/2018 11:15 AM, Florian Weimer wrote:
>> In <https://sourceware.org/ml/libc-alpha/2014-05/msg00506.html>,
>> Joseph suggested to use __USE_GNU for this function, but since most
>> of the BSDs and Illumos have it, I think __USE_MISC is more
>> appropriate.  We have seen some reports of implicit function
>> declarations, resulting in pointer truncation.  Declaring the
>> function for _DEFAULT_SOURCE (i.e., by default, as long as -ansi
>> isn't specified) would avoid such problems.
> 
> This seems reasonable to me. The choice of __USE_GNU was perhaps a
> conservative one since it requires _GNU_SOURCE to be defined on the
> user side and that enables a lot of extensions. Relaxing reallocarray
> to __USE_MISC is a good choice if we are seeing developer problems
> with this e.g. reallocarray is detected in some way at runtime, but
> with the prototype missing (and compiler warnings ignored), and the
> default signature resulting in pointer truncation (int). It's also
> a good choice because the BSDs already have it.

Joseph, do you have any comment on this?

Thanks,
Florian