title: How to emit a Qt signal daily at a given time?
body: <p>I need to notify some objects to clear their cache at new day begins. So, I could create QTimer or something similar and check every ms that now midnight +-5ms or not, but it's not a good idea for me.
  Is there(in QT) any standard mechanisms to get notified about this event without allocating any new object? Something static or living since application's initialization like qApp?
  What would you do in situation like this where you need to do something at 00:00?</p>
  
  <p>UPD:
  I'm looking for fast enough solution. Fast means that I need to clear container in slot as quick as it possible, 'cause since midnight data in the container become invalid. So, there is some other timer which shots every 100ms for instance and it trying to get data from container. I need to clear container with invalid data right before any possible try of getting access.</p>