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Date: Mon, 01 Nov 2010 22:28:36 +0100
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Subject: [Qemu-devel] Re: [PATCH 02/40] elf: Add notes implementation
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To: Alexander Graf <agraf@suse.de>
Cc: Blue Swirl <blauwirbel@gmail.com>, Michael Matz <matz@suse.de>, qemu-devel Developers <qemu-devel@nongnu.org>, Gerd Hoffmann <kraxel@redhat.com>

On 11/01/2010 10:17 PM, Alexander Graf wrote:
> Let's ask someone who definitely knows:).

LOL, hi Michael! :)

> Michael, is code like
>
> char *x = a, *y = b;
> if (x < y) {
>    ...
> }
>
> valid? Or do I first have to cast x and y to unsigned longs or uintptr_t?

It is, as long as x and y point into the same object (in your original 
code, data[0]...data[data_len] is the object).  This instead

   char *x = a;
   long *y = b;
   if (x < y)
     {
     }

should give a warning

   g2.c:1: warning: comparison of distinct pointer types lacks a cast

but is also valid as long as x and y point into the same object.  To 
quiet the warning you should _not_ cast x to long* however (unless you 
know it's properly aligned); casting y to char* instead is fine.

Paolo