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Date: Tue, 02 Jun 2009 09:26:06 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently
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To: David Turner <digit@google.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Paul Brook <paul@codesourcery.com>, qemu-devel@nongnu.org, Jean-Christophe Dubois <jcd@tribudubois.net>

On 05/29/09 23:12, David Turner wrote:
> I would even suggest providing helper macros to make the programmer's intent
> even more clear
> and less error-prone, as in:
>
> #define  QEMU_NEW(ptr)                    (ptr) = qemu_alloc(sizeof(*(ptr)))
> #define  QEMU_NEW_ARRAY(ptr,cnt)   (ptr) = qemu_calloc((cnt),sizeof(*(ptr)))
> #define  QEMU_RENEW_ARRAY(ptr,cnt)  (ptr) =
> qemu_realloc((ptr),(cnt),sizeof(*(ptr)))
> #define  QEMU_FREE_ARRAY(ptr)        qemu_free(ptr)

The idea to have allocators for arrays (and have them allow zero-length 
arrays) is fine.  I wouldn't create two macros for new and renew array, 
you can just use usual realloc semantics (ptr == NULL -> alloc).

Also I don't like the syntax that much as you'll have the IMHO 
non-intuitive code like this:

   QEMU_NEW_ARRAY(ptr, ...);

instead of

   ptr = QEMU_NEW_ARRAY(...);

then.  I don't see another easy way to get the automagic sizeof(*ptr) 
stuff done though.

cheers,
   Gerd