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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: How many wide characters may mbstowcs store?
Date: Sun, 28 Jun 2020 06:32:18 -0700
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Andrey Tarasevich <andreytarasevich@hotmail.com> writes:

> On 5/11/2020 4:30 AM, Philipp Klaus Krause wrote:
>
>> For wcstombs, the wording seems clear to state that it will stop at a
>> terminating 0, but for the mbstowcs it seems unclear to me.
>
> The issue is fairly similar to the one described here
>
> https://trust-in-soft.com/blog/2015/12/21/memcmp-requires-pointers-to-fully-valid-buffers/
>
> The question is whether `memcmp` is allowed to read beyond the first
> differing byte, while still within the specified buffer size.

The question is similar.  The answer isn't.