On Linux we have a problem stopping an InterprocessConnectionServer cleanly. The problem is that it will internally create a Socket and call waitForNextConnection(), which will hang indefinitely if there is no incoming connection.
When stopping the server, it tries to unblock this call by creating a connection (juce_Socket.cpp line 380), but fails. I investigated this a bit but couln't find the problem. I know that in juce_Socket.cpp on line 176 the getsockopt() call returns ECONNREFUSED.
It worked correctly before we upgraded to JUCE 3. Any thoughts on what could be the issue?