[reSIProcate] Help me to understand this code in BasicCall.cxx

[Jia Pu]

     if (!uacShutdownHandler.dumShutDown)
     {
        FdSet fdset;
        dumUac->buildFdSet(fdset);
        int err = fdset.selectMilliSeconds(dumUac->getTimeTillNextProcessMS());
        assert ( err != -1 );
        dumUac->process(fdset);
     }


Can someone explain the purpose of this code? Thanks.