[Kde-bindings] KDE/kdebindings/csharp/qyoto

[Richard Dale]

On Monday 28 May 2007, Arno Rehn wrote:
> Am Montag, 28. Mai 2007 schrieb Richard Dale:
> > SVN commit 669114 by rdale:
> >
> > * Attempted to add a QyotoHash function that will compile on 64 bit
> >   machines
>
> Hmm, that doesn't even compile on my 32 bit machine.
>
> error: invalid operands of types 'void*' and 'unsigned int' to
> binary 'operator&'
>
> When we change it like this:
>
> return (int) (((qint64) o->ptr) & 0xFFFFFFFF);
>
> it works, on both 32 bit and 64 bit.
> In this case we wouldn't even need the "& 0xFFFFFFFF" thing, I think. We
> should be able to just cast first to an qint64, which would make the
> compiler happy, and then to a normal int, which would suit our needs. As
> this is never called on a 64 bit machine, it wouldn't cause any data loss.
> So
>
> return (int) (qint64) o->ptr;
Well I wasn't sure about the sign extension rules for that sort of thing. For 
instance, I'm pretty sure this would work:
return (uint) (quint64) o->ptr;

But with 
return (int) (qint64) o->ptr;

I wondered if the int happened to be negative, whether you still end up with 
the original bit pattern as in the 'o->ptr' if you go via a 'qint64' if you 
don't have the '& 0xFFFFFFFF' part. It might be ok, and without that, and so 
I would change it to whichever you prefer, as the main thing is that it 
compiles rather than fills up a hash table perfectly for now.

-- Richard