I would assume that what it really means is to take packets only from the broadcast IP address as a source (which would be very odd).

I'm surprised that you can call connect for a connection-less socket, but I'm not surprised that it would only cause packets to be accepted form the address you specify to accept packets from. Your request was indeed very odd. Maybe you were thinking of INADDR_ANY. As for the crash upon exiting the thread, I get the following message from strawberry perl:

"Free to wrong pool e64070 not 3f67c8, <STDIN> line 1 during global destruction."

I can confirm that error message is related to threads. Still have nothing to debug.