From: Luca Barbato <lu_zero@gentoo.org>
To: musl@lists.openwall.com
Subject: Re: NULL
Date: Sat, 12 Jan 2013 08:15:21 +0100 [thread overview]
Message-ID: <50F10D89.4050909@gentoo.org> (raw)
In-Reply-To: <20130112064611.GG20323@brightrain.aerifal.cx>
On 12/01/13 07:46, Rich Felker wrote:
> On Sat, Jan 12, 2013 at 12:32:44AM -0600, Rob Landley wrote:
>> On 01/09/2013 07:36:43 AM, John Spencer wrote:
>>>> using NULL in the argument of variadic functions is ub both
>>>> in c and c++
>>>
>>> many developers don't care about the standard. they take the stance:
>>> "works for me, if you want it patched then do it yourself and
>>> we'll eventually merge"
>>
>> Why is it UB? The standard says it's a pointer. If you pull %p off
>> in printf, feeding NULL in that slot should work fine.
>
> See my other message. NULL is not required to have pointer type. It
> can be any null pointer constant, which includes things like 0, 0L,
> 0ULL, (sizeof 1 - sizeof 2), (void *)(1ULL/2ULL), etc.
>
> The %p specifier, on the other hand, requires an argument of type void
> *; passing any other type yields UB.
so printf("%s", NULL) would lead to UB if NULL is 0L ?
lu
next prev parent reply other threads:[~2013-01-12 7:15 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 11:02 NULL John Spencer
2013-01-09 12:18 ` NULL Szabolcs Nagy
2013-01-09 13:36 ` NULL John Spencer
2013-01-12 6:32 ` NULL Rob Landley
2013-01-12 6:46 ` NULL Rich Felker
2013-01-12 7:15 ` Luca Barbato [this message]
2013-01-12 13:33 ` NULL Rich Felker
2013-01-12 11:39 ` NULL Jens Staal
2013-01-09 13:09 ` NULL croco
2013-01-09 13:47 ` NULL John Spencer
2013-01-09 14:49 ` NULL croco
2013-01-09 14:42 ` NULL Luca Barbato
2013-01-09 14:47 ` NULL Rich Felker
2013-01-09 15:03 ` NULL Luca Barbato
2013-01-09 15:18 ` NULL John Spencer
2013-01-09 15:36 ` NULL Rich Felker
2013-01-09 21:11 ` NULL Rob
2013-01-09 21:53 ` NULL Szabolcs Nagy
2013-01-09 22:17 ` NULL Rob
2013-01-09 23:42 ` NULL Szabolcs Nagy
2013-01-12 6:56 ` NULL Rob Landley
2013-01-12 7:07 ` NULL Bobby Bingham
2013-01-12 13:31 ` NULL Rich Felker
2013-01-13 14:29 ` NULL Rob Landley
2013-01-13 14:56 ` NULL Luca Barbato
2013-01-13 16:29 ` NULL Rob Landley
2013-01-13 17:14 ` NULL Luca Barbato
2013-01-13 15:23 ` NULL Strake
2013-01-13 17:17 ` NULL Luca Barbato
2013-01-13 17:47 ` NULL Szabolcs Nagy
2013-01-13 19:46 ` NULL Rob Landley
2013-01-14 6:11 ` NULL Rich Felker
2013-01-14 8:45 ` musl as a framework to test applications' compatibility with POSIX (was: NULL) Vasily Kulikov
2013-01-14 14:03 ` Rich Felker
2013-01-14 14:30 ` Vasily Kulikov
2013-01-14 15:02 ` Szabolcs Nagy
2013-01-14 15:14 ` Rich Felker
2013-01-14 13:19 ` NULL Rob Landley
2013-01-12 5:56 ` NULL Rob Landley
2013-01-12 6:42 ` NULL Rich Felker
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