The QSocketNotifer class provides support for socket callbacks. ... There are three types of socket notifiers (read, write and exception) and you must specify one of these in the constructor. ... socket is the socket to be monitored. type specifies the socket operation to be detected; QSocketNotifier::Read, QSocketNotifier::Write or QSocketNotifier::Exception. ... Returns the socket event type specified to the constructor; QSocketNotifier::Read, QSocketNotifier::Write or QSocketNotifier::Exception. ...