Problem using diary with standalone application

I am developing a MATLAB app using the appdesigner (MATLAB version R2019b), which is intented to be used as standalone '.exe' on Windows. For traceablity I wanted to include a log-file of all outputs. The 'diary()' function seemed to be a good function for this. In my code I have a lot of 'disp(...)' commands (also in code parts that I cannot or do not want to change). The output for these disp-commands works perfectly in the MATLAB command window when I run the application within the MATLAB environment. However, when run it as Windows standalone the behavior is not logical to me: In the WIndows cmd window the output is the same as in the MATLAB command window, but the diary file only logs the output for the 'startupFcn()' and the 'UIFigureCloseRequest()' functions and not for any callback, e.g. here from a button 'DispHelloWorldButtonPushed()'.

Does anybody know how to solve this issue and where it comes from? Btw, also the build-in 'Create log file' option during compilation shows the same behavior as the 'diary' function.

Here is a minimal working example of an app with this behavior:

classdef Test < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure              matlab.ui.Figure
        DispHelloWorldButton  matlab.ui.control.Button
    end

    % Callbacks that handle component events
    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)
            diary(fullfile(pwd,'log.txt'))
            diary on
            disp('Hello World!')
        end

        % Button pushed function: DispHelloWorldButton
        function DispHelloWorldButtonPushed(app, event)
            diary on
            disp('Button: Hello World!')
        end

        % Close request function: UIFigure
        function UIFigureCloseRequest(app, event)
            disp('Bye bye World!')
            diary off
            delete(app)
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';
            app.UIFigure.CloseRequestFcn = createCallbackFcn(app, @UIFigureCloseRequest, true);

            % Create DispHelloWorldButton
            app.DispHelloWorldButton = uibutton(app.UIFigure, 'push');
            app.DispHelloWorldButton.ButtonPushedFcn = createCallbackFcn(app, @DispHelloWorldButtonPushed, true);
            app.DispHelloWorldButton.Position = [159 161 311 175];
            app.DispHelloWorldButton.Text = 'Disp(''Hello World!'')';

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = Test

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Answer 1

[Garmit Pant]

Hello Jonathan

The issue you're experiencing is due to the way MATLAB handles the standard output and the “diary” functionality when running as a standalone executable.

The ”diary” function logs the MATLAB Command Window to a text file. Since the standalone application is not running in the MATLAB environment, the Command Window is not in use and thus the “diary” function doesn’t work.

You can use the “fprintf” function to log the outputs to a log-file. You can add a private function to the app using 'Function' button in the ‘Editor’ tab. The following code snippet demonstrates how to write the custom function to log messages and use it:

classdef Test < matlab.apps.AppBase 
    % Properties that correspond to app components 
    properties (Access = public) 
        UIFigure              matlab.ui.Figure 
        DispHelloWorldButton  matlab.ui.control.Button 
        LogFileID             % File ID for the log file 
    end 
    
    % Callbacks that handle component events 
    methods (Access = private) 
        
        % Custom logging function 
        function logMessage(app, message) 
            if ~isempty(app.LogFileID) 
                fprintf(app.LogFileID, '%s\n', message); 
            end 
            fprintf('%s\n', message); % Also print to command window 
        end 
        
        % Code that executes after component creation 
        function startupFcn(app) 
            app.LogFileID = fopen(fullfile(<insert path to file>,'a'); 
            app.logMessage('Hello World!'); 
        end 
        
        % Button pushed function: DispHelloWorldButton 
        function DispHelloWorldButtonPushed(app, event) 
            app.logMessage('Button: Hello World!'); 
        end 
        
        % Close request function: UIFigure 
        function UIFigureCloseRequest(app, event) 
            app.logMessage('Bye bye World!'); 
            if ~isempty(app.LogFileID) 
                fclose(app.LogFileID); 
            end 
            delete(app) 
        end 
    end 
    
    % Component initialization 
    methods (Access = private) 
        
        % Create UIFigure and components 
        function createComponents(app) 
            % Create UIFigure and hide until all components are created 
            app.UIFigure = uifigure('Visible', 'off'); 
            app.UIFigure.Position = [100 100 640 480]; 
            app.UIFigure.Name = 'UI Figure'; 
            app.UIFigure.CloseRequestFcn = createCallbackFcn(app, @UIFigureCloseRequest, true); 
            
            % Create DispHelloWorldButton 
            app.DispHelloWorldButton = uibutton(app.UIFigure, 'push'); 
            app.DispHelloWorldButton.ButtonPushedFcn = createCallbackFcn(app, @DispHelloWorldButtonPushed, true); 
            app.DispHelloWorldButton.Position = [159 161 311 175]; 
            app.DispHelloWorldButton.Text = 'Disp(''Hello World!'')'; 
            
            % Show the figure after all components are created 
            app.UIFigure.Visible = 'on'; 
        end 
    end 
    
    % App creation and deletion 
    methods (Access = public) 
        
        % Construct app 
        function app = Test 
            % Create UIFigure and components 
            createComponents(app) 
            
            % Register the app with App Designer 
            registerApp(app, app.UIFigure) 
            
            % Execute the startup function 
            runStartupFcn(app, @startupFcn) 
            
            if nargout == 0 
                clear app 
            end 
        end 
        
        % Code that executes before app deletion 
        function delete(app) 
            % Delete UIFigure when app is deleted 
            delete(app.UIFigure) 
        end 
    end 
end 

I hope you find the above explanation and suggestions useful!

[Jonathan Berthold]

I appreciate your suggestion. However, this is not an option for me because within my callbacks (e.g. button) I am also calling functions (containing disp) that I do not want to edit and that are also not connected directly to the app (so I cannot call app.logMessage). The only possiblity for me would be to use the disp() command, which already exists within these functions.

I was more wondering what is different for the disp command used during startupFcn/UIFigureCloseRequest compared to the other app callbacks when used as standalone with no MATLAB command window existent. And can one eliminated the difference between these callbacks so the diary can still be used with disp even without a MATLAB command window?

[Garmit Pant]

Hi Jonathan

I investigated a little further and there might be an issue with the usage of "diary" function in the code snippet that you have shared. If "filename" input argument to the "diary" function does not include a full path, MATLAB redetermines the path of the file relative to the current folder every time logging is enabled. If the current folder has changed since the last time logging was enabled, MATLAB might save the log to a different file. The following code snippet will help you log your callbacks using "disp" and "diary":

classdef Test < matlab.apps.AppBase
    % Properties that correspond to app components
    properties (Access = public)
        UIFigure              matlab.ui.Figure
        DispHelloWorldButton  matlab.ui.control.Button
    end
    
    % Callbacks that handle component events
    methods (Access = private)
        
        % Code that executes after component creation
        function startupFcn(app)
            diary(fullfile(<file path>))
            disp('Hello World! Latest')
        end
        
        % Button pushed function: DispHelloWorldButton
        function DispHelloWorldButtonPushed(app, event)
            disp('Button: Hello World!')
        end
        
        % Close request function: UIFigure
        function UIFigureCloseRequest(app, event)
            disp('Bye bye World! Latest')
            diary off
            delete(app)
        end
    end
    
    % Component initialization
    methods (Access = private)
        
        % Create UIFigure and components
        function createComponents(app)
            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';
            app.UIFigure.CloseRequestFcn = createCallbackFcn(app, @UIFigureCloseRequest, true);
            
            % Create DispHelloWorldButton
            app.DispHelloWorldButton = uibutton(app.UIFigure, 'push');
            app.DispHelloWorldButton.ButtonPushedFcn = createCallbackFcn(app, @DispHelloWorldButtonPushed, true);
            app.DispHelloWorldButton.Position = [159 161 311 175];
            app.DispHelloWorldButton.Text = 'Disp(''Hello World!'')';
            
            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end
    
    % App creation and deletion
    methods (Access = public)
        
        % Construct app
        function app = Test
            % Create UIFigure and components
            createComponents(app)
            
            % Register the app with App Designer
            registerApp(app, app.UIFigure)
            
            % Execute the startup function
            runStartupFcn(app, @startupFcn)
            
            if nargout == 0
                clear app
            end
        end
        
        % Code that executes before app deletion
        function delete(app)
            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

[Jonathan Berthold]

Hello Garmit, that was also one of my first thoughts. Unfortunally, it does not make any difference. As you can see in my code snippet, I also used an absolute path already using the function 'pwd', e.g., "fullfile(pwd, 'log.txt'). Writing the path out explicitely does not change anything, sadly. Also adding an additional cd(<path to diray file>) in the button callback did not help. Thanks for your support, though!

[Garmit Pant]

Hi Jonathan

Did you try changing how you are handling toggling "diary" to 'on' and 'off'? I have made some changes to that in the code snippet above. Specifically, I have removed the "diary on" statements in your code. The following statement also switches on logging:

diary(fullfile(<file path>))

GIven that you are toggling logging on multiple times using the "diary on" statement, the path of the log file could be changing. Please try to incorporate the code snippet in the comments since I was able to successfully log to a file using the "diary" function that way.

[Jonathan Berthold]

Hi Garmit,

I now found that the problem is somewhat deeper than I expected. I now tried the standalone app on a different machine and the diary worked in all cases! So what I can tell is that it works on MS Windows 10, Version 1809 but not on a MS Windows Server 2016, Version 1607 (which I use for development & testing). Maybe that helps you in finding the error with the different handling of the callbacks. Let me know what you think.