Simulink model callback: Output to command line suppressed

It seems that in the evaluation of model callbacks by Simulink, output to command lines, like

display('Hello World!')

is suppressed. Is this true? If yes, which other MATLAB commands are not evaluated in model callbacks?

[Bonpland]

As it turns out, this "feature" has been come up with by Simulink some time ago. Is there a workaround to enforce display of text in model callbacks?

Answer 1

[Shlok]

Hi Bonpland,

Yes, the "display" function is now deprecated, and you'll start seeing a warning popup about it in R2022b and later versions.

Since, using “display” in your code may lead to warnings or unexpected behaviour, you can use “disp” or “fprintf” for displaying messages in MATLAB.

For example, in Simulink model callbacks, you can use “disp” as follows:

% Using ‘disp’ to display a message in the Simulink Diagnostic Viewer  
disp('Hello World!'); 

You can also write output to a file using “fprintf”.:

fid = fopen('output.txt', 'a');  
fprintf(fid, 'Hello World!\n');  
fclose(fid); 

The above methods ensure that your messages are displayed or logged appropriately without relying on the deprecated “display” function.

You can refer the following MathWorks documentation link to learn more about these alternatives:

https://www.mathworks.com/help/matlab/ref/codecompatibilityreport.html