Qt 4.5 to be LGPL

[Bill Baxter]

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