Qt 4.5 to be LGPL

[Eldar Insafutdinov]

Yigal Chripun Wrote:

> Bill Baxter wrote:
> > On Fri, Jan 16, 2009 at 10:22 AM, Walter Bright
> > <newshound1 at digitalmars.com>  wrote:
> >> Bill Baxter wrote:
> >>> On Fri, Jan 16, 2009 at 9:00 AM, Yigal Chripun<yigal100 at gmail.com>  wrote:
> >>>
> >>>> 2. there's more to S&S than just an array of delegates - they are weak
> >>>> refs
> >>>> so that destruction of an object disconnects automatically the apropriate
> >>>> signals. but there is a weakref lib for D written by Bill IIRC, that
> >>>> could
> >>>> be utilized in qtD. no pre-processor needed.
> >>> The "delegates" in Qt are more like a QObject,QString pair.  The
> >>> object and the *name* of the method to call.
> >>>
> >>> And there aren't really "weak refs" in Qt.  When you connect a signal
> >>> and slot it also makes some extra connections between the two objects'
> >>> destroyed() signals.  So each object is also listening for the other
> >>> object to be destroyed.   Sort of a weak ref, but more like a strong
> >>> ref with active notifications about destruction either way.   In a
> >>> GC'ed language with real weak refs, the slot holder doesn't have to
> >>> worry if the signal sender disappears.
> >> This is taken care of in std.signals.
> >
> > WeakRef Yigal was referring to is just a handy wrapper class for the
> > same GC callback that std.signals uses.  Plus it's compatible with
> > both Phobos and Tango.
> >
> > --bb
> 
> What I meant was that QT provides the functionality of a weakref, but 
> you're right that that's not a "real" weak ref.
> still, I think this functionality need to be implemented in qtD and 
> luckily D does have true weakrefs that can be utilized for this.
> 
> Question: since D2 now uses the same runtime as tango and that includes 
> the (same) GC, do we still need the wrapper, for D2 code?

What do you mean by wrapper? Or you mean extern C++ capabilites of D2? I tried them, and they seem really poor. Besides nobody who I was asking knows when D2 finally stabilise and goes out of beta, tango for example isn't going to be ported to D2 in nearest future.