[Qt-interest] Using QSslSocket with QTcpServer results in segfault

[Nikos Chantziaras]

On 12/06/2009 10:04 AM, Thiago Macieira wrote:
> Em Domingo 6. Dezembro 2009, às 08.50.54, Nikos Chantziaras escreveu:
>> The rest of the "Fortune Server" app stays the same.  However, when
>> connecting to the server, the application crashes instantly with:
>>
>>     QObject::connect: Cannot connect (null)::disconnected() to
>>     (null)::deleteLater()
>>     Segmentation fault
>>
>> What am I doing wrong?
>
> Nothing in your paste says either "disconnected" or "deleteLater". So it's not
> in the parts you pasted, but somewhere else.
>
> There, you're connecting a null pointer's signal to its slot. What happened
> next is anyone's guess (since you didn't paste it): mine is that you called
> something on that null pointer, which resulted in the crash.

You are right.  It seems I made the wrong assumption that QSslSocket can 
be used as a drop-in replacement for QTcpSocket like this:

   QTcpSocket* socket = fTcpServer->nextPendingConnection();
   connect(socket, SIGNAL(disconnected()), socket, SLOT(deleteLater()));

fTcpServer actually points to an SslServer object and in this case 
nextPendingConnection() returns 0.  I was trying to use polymorphism 
here in order to leave that code alone.  But I guess it's never that easy :P