Question

I’m in a worker thread and want to sleep for a specified period of time (usually a few hundreds milliseconds), but the sleep should be interruptible. Here is what I have come up with

void DummyScope::sleepForSamples() {
   if(m_sampleSleep < 100) {
      MySleeper::sleep(m_sampleSleep);
      return;
   }

   // sleep in periods of 100 ms, to be responsible for shutdown requests      
   qint64 t = QDateTime::currentMSecsSinceEpoch();
   qint64 end = t + m_sampleSleep;

   while(t + 100 <= end) {
      MySleeper::sleep(100);
      t = QDateTime::currentMSecsSinceEpoch();

      // TODO: check here whether we are interrupted
   }

   if(end > t) {
      MySleeper::sleep(end - t);
   }
}

However that looks a bit convoluted and I wonder whether there’s a better way to do this. Is using a QWaitCondition with a timeout-wait a better solution?

Answer 1

‘Is using a QWaitCondition with a timeout-wait a better solution?’

Yes!

The sleep() loop, apart from needlessly running every 100ms, has an average ‘interrupt’ latency of 50ms.