How to declare an global error listener in App Designer?

I'm trying to make an app that will use .m files to do Digital Signal Processing tasks on various inputs and I want to catch and propagate MATLAB System Errors such as issues with a MATLAB System Object, System Out of RAM etc back to the user who is using the application.

[Mario Malic]

try and catch blocks could be useful.

[Rik]

Bottom line: there is no general solution to this problem. You will have to implement everything with try-catch-blocks and deal with errors appropriately. I'm working on a set of functions that will allow you to do this more easily, but they are not quite ready for separate publication.

Answer 1

[Gayatri Rathod]

Hi Meet,

• To catch and propagate MATLAB System Errors in your app, you can use a try-catch block in your code. When a MATLAB System Object throws an error, it generates an exception which can be caught using a try-catch block. You can then propagate the error message back to the user by displaying it in the app or logging it.

Here's an example of how you can catch and propagate an error in MATLAB:

try 
    % Your DSP code here 
    y = filter(b,a,x); % Example DSP task
catch ME 
    % Catch the error and propagate it back to the user 
    error_msg = sprintf('Error in DSP task:\n%s', ME.message); 
    errordlg(error_msg, 'DSP Error', 'modal'); 
end

• In this example, the try block contains your DSP code. If an error occurs, MATLAB generates an exception which is caught by the catch block. The ME variable holds the exception object, which contains information about the error, including the error message.
• You can then create your own error message using sprintf and display it to the user using a dialog box.
• There are different types of MATLAB System Errors, and you can catch them specifically using different catch statements. For example, to catch out of memory errors, you can use the following catch statement:

catch ME 
    if strcmp(ME.identifier, 'MATLAB:nomem') 
        % Handle out of memory error 
    else 
        % Handle other errors 
    end 
end 

• This will catch only out of memory errors and handle them differently from other errors. You can find more information about MATLAB System Errors and how to handle them in the MATLAB documentation.

You can read more about the try, catch and errordlg from the following documentations:  try & catch Documentation, errordlg Function.

Hope it helps!  

Regards,

Gayatri Rathod