[Qemu-devel] Re: [PATCH 02/40] elf: Add notes implementation

[Paolo Bonzini]

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