MATLAB: TIMER still runs after deleting the variable

stopping a timer.

   currentTimeSecs = rem(now,1)*24*60*60;
   fireTimerAtSecs = 15*60*60;
   if currentTimeSecs < fireTimerAtSecs
       % timer will fire today
       timerDelaySecs = fireTimerAtSecs - currentTimeSecs;
   else
       % timer will fire tomorrow
       timerDelaySecs = (24*60*60 - currentTimeSecs) + fireTimerAtSecs;
   end
   T = timer('Period',120,                 ...
             'ExecutionMode','fixedRate',  ... 
             'StartDelay', timerDelaySecs, ...
             'TimerFcn',@(src,evt)disp('hi'));
   start(T);
When I run the above code and then delete the variable T then the script still continues running and executing the function disp(hi). How can I stop that? how can i stop the timer?

Best Answer

Check out this snippet of code that I wrote to stop all timers. Works even if you have lost the handle to some timer you started up:
%--------------------------------------------------------------------------------------------------------------------------
function StopTimer(handles)
try
  fprintf('Entering StopTimer...\n');
  listOfTimers = timerfindall % List all timers, just for info.
  % Get handle to the one timer that we should have.
  if isempty(listOfTimers)
    % Exit if there is no timer to turn off.
    fprintf('There are no timers to turn off. Leaving StopTimer().\n');
    return;
  end
  handleToTimer = getappdata(handles.figMainWindow, 'timerObj');
  % Stop that timer.
  stop(handleToTimer);
  % Delete all timers from memory.
  listOfTimers = timerfindall
  if ~isempty(listOfTimers)
    delete(listOfTimers(:));
  end
  fprintf('Left StopTimer and turned off all timers.\n');
catch ME
  errorMessage = sprintf('Error in StopTimer().\nThe error reported by MATLAB is:\n\n%s', ME.message);
  fprintf('%s\n', errorMessage);
  uiwait(warndlg(errorMessage));
end
return; % from StopTimer
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