Re: [Qemu-devel] [PATCH] loader: don't call realloc(O) when no symbols are present

[malc]

On Tue, 29 Dec 2009, Jamie Lokier wrote:

> malc wrote:
> > On Mon, 28 Dec 2009, Jamie Lokier wrote:
> > 
> > > Aurelien Jarno wrote:
> > > > This fixes the loading of a stripped kernel with zero malloc disabled.
> > > 
> > > *Raises an eyebrow*
> > > 
> > > Even though there's different perspectives over whether qemu_malloc(0)
> > > should be allowed, inherited from ambiguity over malloc(0),
> > > realloc(p,0) has always had a standard, well-defined meaning.
> > 
> > No.
> > http://groups.google.com/group/comp.std.c/browse_thread/thread/4e9af8847613d71f/6f75ad22e0768a0b?q=realloc++group:comp.std.c#6f75ad22e0768a0b
> 
> Wow, thanks for that.  It's a real surprise.  Looks like C99's own
> rationale is not consistent with itself on the subject, and differs
> from C90 where the "standard, well-defined meaning" I referred to was
> defined.

Yep.

> 
> See also http://c-faq.com/malloc/reallocnull.html which says "and the
> related realloc(..., 0), which frees" and has references at the end.
> See, it's not just me :-)

Nope not just you, even glibc still uses C90 behaviour.

> So thanks for setting me straight.  One thing we can all agree on now
> is that it's best not to call malloc(0) or realloc(p,0) at all :-)

Indeed.

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