How do I add character to a string in Simulink/Simevents?

Is there a way to append characters from array in Simulink/Simevents? I have tried to add characters to an empty string using strcat and append in Simulink/Simevents, but I am getting the following error:

Incorrect size for expression '<output of strcat>': expected [1x0] but found [1x1].

Incorrect size for expression '<output of append>': expected [1x0] but found [1x1].

Is there a way to make this work? or is there another way to append characters to an empty string in Simulink/Simevents? The following is the code I am using. Thank you.

memory is an array with 10 0s.

[Walter Roberson]

I wonder if you could use string() objects?

https://www.mathworks.com/help/simulink/ug/simulink-strings.html

Answer 1

[Mark McBroom]

Simulink doesn't like the fact that the variable s grows in length. Try something like this:

.....
    
s = repat(' ',1,10);   % create char array of max size
s_counter = 0;
for c=1:length(entity.memory)
    if(entity.memory( c ) ~= 0
        s_counter = s_counter + 1;
        s(s_counter) = entity.memory( c );
    end
end
fprintf('%s\n', s);