linux-kernel - Re: [PATCH] Cleanup: snprintf() always NUL-terminates: depend on it

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Date:	Mon, 12 Jan 2015 13:07:38 +0400
From:	Aleksandr P <alexpikptz@...il.com>
To:	me@...tis.eu
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Cleanup: snprintf() always NUL-terminates: depend on it

>   len = snprintf(fname, 99, "%s", buf);
> - fname[len-1] = '\0';

> I just deleted that "really, really" NUL-termination line because
> it was based on a misunderstanding of snprintf()'s postcondition.

Are you sure this code can be simple deleted? It does not only
terminate the string but deletes the last character. According to man:
" Upon successful return, these functions return the number of
characters printed (EXCLUDING the null  byte  used  to end output to
strings)."
So, if buf was "abc" len would be 3 and fname would become "ab".

Best regards,
Alexandr
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