Task #2669: Fail instead of freeze if the Delay thread terminates prematurely

RTCP/IONProc/src/Delays.cc

@@ -195,6 +195,10 @@ void Delays::mainLoop()
       bufferUsed.up(itsNrCalcDelays);
     }
   } catch (AipsError &ex) {
+    // trigger getNextDelays and force it to stop
+    stop = true;
+    bufferUsed.up(1);
+
     THROW(IONProcException, "AipsError: " << ex.what());
   }
 
@@ -210,8 +214,13 @@ void Delays::getNextDelays(Matrix<MVDirection> &directions, Matrix<double> &dela
   ASSERTSTR(delays.num_elements() == itsNrBeams * (itsMaxNrPencilBeams + 1),
 	    delays.num_elements() << " == " << itsNrBeams << "*" << (itsMaxNrPencilBeams + 1));
 
+  ASSERT(itsThread);
+
   bufferUsed.down();
 
+  if (stop)
+    THROW(IONProcException, "Cannot obtain delays -- delay thread stopped running");
+
   // copy the directions at itsBuffer[head] into the provided buffer,
   // and calculate the respective delays
   for (unsigned b = 0; b < itsNrBeams; b ++) {