QT socket non blocking mode

Is there any way to put qt sockets in blocking or non blocking mode? Are they in default in non blocking mode. Do qt needs to have blocking or non blocking sockets because it already puts this in a kind of non blocking functionality by using signal and slots?

For performance reasons sockets should be non-blocking. Otherwise this blocks the event loop and freezes the UI. You can make them pseudo-blocking by using the family of waitFor* methods.