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From: Marek Vasut <marek.vasut@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] Prevent malloc with size 0
Date: Mon, 2 Apr 2012 06:23:50 +0200	[thread overview]
Message-ID: <201204020623.50669.marek.vasut@gmail.com> (raw)
In-Reply-To: <CALButCKJLDhkbiMgc1S22V-VtjMp_X5i8yv2jdyLqvAyO8V=3w@mail.gmail.com>

Dear Graeme Russ,

> Hi Marek,
> 
> On Mon, Apr 2, 2012 at 1:36 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
> > Dear Mike Frysinger,
> > 
> >> On Sunday 01 April 2012 20:25:44 Graeme Russ wrote:
> >> > b) The code calling malloc(0) is making a perfectly legitimate
> >> > assumption
> >> > 
> >> >    based on how glibc handles malloc(0)
> >> 
> >> not really.  POSIX says malloc(0) is implementation defined (so it may
> >> return a unique address, or it may return NULL).  no userspace code
> >> assuming malloc(0) will return non-NULL is correct.
> > 
> > Which is your implementation-defined ;-) But I have to agree with this
> > one. So my vote is for returning NULL.
> 
> Also, no userspace code assuming malloc(0) will return NULL is correct
> 
> Point being, no matter which implementation is chosen, it is up to the
> caller to not assume that the choice that was made was, in fact, the
> choice that was made.
> 
> I.e. the behaviour of malloc(0) should be able to be changed on a whim
> with no side-effects
> 
> So I think I should change my vote to returning NULL for one reason and
> one reason only - It is faster during run-time

Well, this still might break some code which assumes otherwise ... like you 
said. And like I said, let's break it because it worked only be a sheer 
coincidence ;-)

> Regards,
> 
> Graeme

Best regards,
Marek Vasut

  reply	other threads:[~2012-04-02  4:23 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-21  9:24 [U-Boot] [PATCH] Prevent malloc with size 0 Kostaras Nikolaos
2010-10-21 11:25 ` Joakim Tjernlund
2010-10-21 11:32   ` Wolfgang Denk
2010-10-21 11:45     ` Joakim Tjernlund
2010-10-21 11:51       ` Wolfgang Denk
2010-10-21 11:56         ` Joakim Tjernlund
2010-10-21 12:02           ` Wolfgang Denk
2010-10-21 12:54             ` Joakim Tjernlund
2010-10-21 19:51       ` Mike Frysinger
2010-10-21 21:10         ` Graeme Russ
2010-10-21 21:27           ` Mike Frysinger
2012-03-31 19:59             ` Marek Vasut
2012-04-01 12:25               ` Joakim Tjernlund
2012-04-01 14:01                 ` Marek Vasut
2012-04-01 14:15                   ` Joakim Tjernlund
2012-04-01 14:21                     ` Marek Vasut
2012-04-01 22:40                       ` Graeme Russ
2012-04-01 23:45                         ` Marek Vasut
2012-04-01 23:52                           ` Graeme Russ
2012-04-02  0:13                             ` Marek Vasut
2012-04-02  0:25                               ` Graeme Russ
2012-04-02  1:04                                 ` Marek Vasut
2012-04-02  1:40                                   ` Graeme Russ
2012-04-02  2:51                                     ` Marek Vasut
2012-04-02  3:05                                       ` Graeme Russ
2012-04-02  6:39                                         ` Joakim Tjernlund
2012-04-02  3:12                                 ` Mike Frysinger
2012-04-02  3:16                                   ` Graeme Russ
2012-04-02  3:36                                   ` Marek Vasut
2012-04-02  3:43                                     ` Graeme Russ
2012-04-02  4:23                                       ` Marek Vasut [this message]
2012-04-02  4:27                                         ` Graeme Russ
2012-04-02  6:55                                       ` Joakim Tjernlund
2012-04-02  7:17                                         ` Graeme Russ
2012-04-02  7:40                                           ` Joakim Tjernlund
2012-04-02 14:05                                             ` Marek Vasut
2012-04-02 14:26                                               ` Joakim Tjernlund
2012-04-02 14:42                                                 ` Marek Vasut
2012-04-02 15:08                                                   ` Joakim Tjernlund
2012-04-02 15:23                                                     ` Marek Vasut
2012-04-02 16:00                                                       ` Joakim Tjernlund
2012-04-02 16:39                                                         ` Marek Vasut
2012-04-02 17:22                                                           ` Joakim Tjernlund
2012-04-02 18:00                                                             ` Marek Vasut
2012-04-02 18:40                                                               ` Joakim Tjernlund
2012-04-02 19:14                                                                 ` Mike Frysinger
2012-04-02 21:02                                                                   ` Joakim Tjernlund
2012-04-02 19:23                                                                 ` Marek Vasut
2012-04-02 20:28                                             ` Graeme Russ
2012-04-02 20:56                                               ` Joakim Tjernlund
2012-04-02 20:59                                                 ` Graeme Russ
2012-04-02 21:14                                                   ` Joakim Tjernlund
2012-04-02 23:35                                                     ` Graeme Russ
2012-04-03 10:35                                                       ` Graeme Russ
2012-10-16  6:31                                                         ` Marek Vasut
2012-10-16  9:22                                                           ` Joakim Tjernlund
2012-10-16 10:43                                                             ` Marek Vasut
2012-10-16 11:46                                                               ` Joakim Tjernlund
2012-10-16 10:43                                                           ` Wolfgang Denk
2012-10-16 22:41                                                             ` Graeme Russ
2012-04-02  3:10                         ` Mike Frysinger
2012-04-02  3:36                           ` Marek Vasut
2010-10-22  6:10         ` Joakim Tjernlund
2010-10-22  7:18           ` Reinhard Meyer
2010-10-22  7:47             ` Joakim Tjernlund
2010-10-22  7:20           ` Mike Frysinger
2010-10-22  7:37             ` Joakim Tjernlund
2010-10-22  7:55               ` Mike Frysinger
2010-10-22  8:34                 ` Joakim Tjernlund
2010-10-22 15:18                   ` Mike Frysinger
2010-10-22 16:40                     ` Joakim Tjernlund
2010-10-22 17:06                       ` Mike Frysinger
2010-10-23  9:14                         ` Joakim Tjernlund
2010-10-22 17:36                 ` Scott Wood
2010-10-23  9:23                   ` Joakim Tjernlund

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