[U-Boot] [PATCH] Prevent malloc with size 0

Marek Vasut
2012-04-02T04:23:50Z

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