[Interest] MultiCast problem. QAbstractSocket::ShareAddress no effect?

[Guido Seifert]

> In the example that you showed (in your previous mail), did bind() return
> true? The docs state that the the socket must be in 'BoundState' for
> joinMulticastGroup() to work (otherwise it returns false). Maybe you can

Hi, I am now quite sure that it is a bug. And more importantly not a stupid bug in my code. :-)

I 'dropped' my code and used the multicastreceiver from the Qt network examples for further tests. The only thing I changed in this code is the groupaddress to 239.255.255.250 and the port to 1900. Under Windows (Windows 7/mingw-4.8.1/Qt-5.1.1/all 64bit) I can see the UPnP multicast messages when I start XBMC on the same machine. Under Linux (gcc 4.8.1/Qt-5.1.1/Debian Sid/64bit) no such messages are shown. According to wireshark none are sent. Naturally, if this port is blocked by multicastreceiver.  

And just now I checked the return value of bind under Linux.
The first time I get 'true'. When I start a second instance of multicastreceiver I get 'false'.  

I just reported it:
https://bugreports.qt-project.org/browse/QTBUG-33419

Guido