Re: [Valgrind-users] posix_memalign is not handled in valgrind?

[Tom H. <th...@cy...>]

In message <106...@ix...>
          Jeremy Fitzhardinge <je...@go...> wrote:

> On Thu, 2003-11-27 at 15:55, Tom Hughes wrote:
> >     /* Test whether the SIZE argument is valid.  It must be a power of
> >        two multiple of sizeof (void *).  */
> >     if (size % sizeof (void *) != 0 || (size & (size - 1)) != 0)
> >        return VKI_EINVAL /*22*/ /*EINVAL*/;
> > Specifically by the second half of the or condition, which doesn't
> > seem to make any sense to me.
> 
> N & (N-1) == 0 iff N is a power of 2 - it's the quick idiom to see if a
> number is a power of 2 or not.

I realised that I just couldn't understand why it wanted to insist
on the size begin a power of two ;-) After reading the manual page
it became obvious where the mistake was.

Tom

-- 
Tom Hughes (th...@cy...)
Software Engineer, Cyberscience Corporation
http://www.cyberscience.com/