[Kde-bindings] Moving the Qyoto C# bindings from playground to kdebindings

[Phil Thompson]

On Wednesday 11 April 2007 11:27 pm, Arno Rehn wrote:
> Am Mittwoch, 11. April 2007 schrieb Richard Dale:
> > On Wednesday 11 April 2007, Richard Dale wrote:
> > > On Wednesday 11 April 2007, Arno Rehn wrote:
> > > > I found out about a little bug in the GetHashCode() stuff of the
> > > > Qyoto classes. When you call the method of certain classes, e.g.
> > > > QTextBlock, the whole app segfaults with no further output. I would
> > > > just return the real pointer to the underlying C++ object, this would
> > > > always be unique and would work, wouldn't it?
> > >
> > > Yes, that's exactly what I was intending it to do. But I was wondering
> > > about 64 bit pointers though, if the hash is an int.
> >
> > Just been looking in the Qt libs, and there's a qHash() function in the
> > QHash class that takes a ulong and returns a uint:
> >
> > inline uint qHash(ulong key)
> > {
> >     if (sizeof(ulong) > sizeof(uint)) {
> >         return uint((key >> (8 * sizeof(uint) - 1)) ^ key);
> >     } else {
> >         return uint(key);
> >     }
> > }
> >
> > So maybe calling that on the C++ pointer would be good enough.
>
> Yes, that looks good.

Note that this isn't reliable - you can have any number of different (nested) 
data structures at the same address. I think I've only ever seen it happen 
once in Qt (Qt v2.x I think) but it was a nasty bug to track down.

Phil