MATLAB: Matlab timer doesnt work in stand alone application

MATLAB Compilertimer

Hi Guys,

i have built this application that listens to a certain folder and continuously checks if certain files appear in it. once these files appear i activate another function to process them. I implemented the folder listener using a Timer object with a fixed rate of 30 sec. (i.e – every 30 sec it should check the content of the folder.) Everything works great when i run the code from within Matlab, yet when i compile and then deploy the app the timer only executes once and then exits the program.

any idea what can cause this difference between compiled and un-compiled versions?

system is Ubuntu 14.04,

timer object instance:

myTimer = timer('TimerFcn',@checkFolderForChanges,'Period',h.listenerInterval,'ExecutionMode','fixedSpacing','BusyMode','queue','UserData',userData);

compile arguments:

mcc -mv fileWatch.m

debug lines i added to monitor the timer, from within Maltab:

timer running mode: on
timer tasksExecuted mode: 682
timer running mode: on
timer tasksExecuted mode: 683
stand alone deployed version (exits after 1 timer task execution:
timer running mode: on
timer tasksExecuted mode: 1
vncuser@mathlab:~/visualizer$

Best Answer

http://www.mathworks.com/matlabcentral/answers/283132-timer-does-not-work-in-the-exe-file#answer_221301

Related Solutions

MATLAB: Does the serial port code stop prematurely when I deploy it with the MATLAB Compiler

This is due to how the deployed application determines when to stop executing. Since the callbacks run seperately from the rest of the MATLAB code, the function you wrote exits normally. The application then terminates the MCR and exits because the function stopped.

You can force the application to keep running by forcing the function to not return immediately. The following code demonstrates how this can be done using a TIMER object and the WAITFOR function:

% Create the timer
tmr = timer;
% Set the timer so that it repeately runs.
tmr.ExecutionMode = 'fixedSpacing';
% You need to set some function as a callback.
% This simply prints an empty string.
tmr.TimerFcn = @(varargin)(fprintf(''));
% You can't wait for a timer with infinite TasksToExecute, so set it really
% large instead.
tmr.TasksToExecute = 1e12;
start(tmr)
% Add normal code here
% Wait ~forever (1e12 seconds)
waitfor(tmr);
% Stop the timer (must be used if you CTRL-C this script)
stop(tmr)
% These commands can be used to stop and clear up any stray timers
stop(timerfindall)
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MATLAB: How to close a MATLAB GUI by using count down timer

Dongyan - the solution will differ depending upon how you have created your GUI (GUIDE, programmatically, or App Designer) but the general idea will be the same. Your GUI will need a timer that exists for the lifetime of the GUI (so the timer cannot be a local variable within some function or method). At some point (pushbutton callback for example), you will initialize a timer with a period (one second), number of tasks to execute (10), and a callback function (that will fire as per your one second period). See Create object to schedule execution of MATLAB commands for details. If your GUI is built with GUIDE, then the following code could be put in whichever function callback that needs to start the timer

 handles.timer = timer('Name','MyTimer',               ...
                       'Period',1,                    ... 
                       'StartDelay',1,                 ... 
                       'TasksToExecute',10,           ... 
                       'ExecutionMode','fixedSpacing', ...
                       'TimerFcn',{@timerCallback,handles.figure1}); 
 guidata(hObject,handles);
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Note how we assign the timer to the handles structure and then call guidata to save that change. Also note how we pass in to the callback the handle to the figure. We do this so that the timer callback can access the GUI to either update the countdown text or to close the GUI. This code may look like

 function [] = timerCallback(hTimer,~,guiHandle)
 if ~isempty(guiHandle)
      % get the handles
      handles = guihandles(guiHandle);
      
      % get the current task number (1,2,3,...,10)
      tasksExecuted = get(hTimer, 'TasksExecuted');
      tasksToExecute = get(hTimer, 'TasksToExecute');
      
      % update the text control with the seconds remaining (note the tasksExecuted counts upwards)
      
      % close the GUI
      if tasksExecuted == tasksToExecute
          close(guiHandle);
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 end

The above is untested so there might be some gotchas especially around closing the GUI.

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