Simulink callbacks not displaying text in MATLAB command window

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Typically I add the following callbacks to all of my Simulink models which displays the simulation start time, end time, and elapsed time in the main command window.
TS = clock;
TS_dis = ['Simulation Start Time: ' datestr(clock)];
TE = clock;
TE_dis = ['Simulation End Time: ' datestr(clock)];
Elapsed_Time = etime(TE,TS);
T_Min = floor(Elapsed_Time/60);
T_Sec = rem(Elapsed_Time,60);
TElap_disp = ['Elapsed Simulation Time: ' num2str(T_Min) ' Minutes ' num2str(T_Sec) ' Seconds'];
This code has worked well up to 2014a however in 2014b this code outputs to the diagnostics viewer which is much less convenient. Is there any way to change where the disp() command outputs text to?

Accepted Answer

Stefanie Schwarz
Stefanie Schwarz on 3 Jul 2019
This output redirection is occurring due to the introduction of Diagnostic Viewer in R2014a.
Please see below MATLAB Answers Post for details and possible workarounds:

More Answers (5)

Sean de Wolski
Sean de Wolski on 30 Jul 2015
fprintf(2,'Hello World')
Will pipe to the command line in red (standard error).
  1 Comment
Jim Johnson
Jim Johnson on 17 May 2016
I had the same issue, the callback would output to the command window in R2014b but not in R2015b. So I used the fprintf(2,'Displayed Text') solution and it does output to the command window but in RED as if it is an error. Is there some way to circumvent this, e.g., tell fprintf to print to the command window instead of the standard error such as fprintf(command_window,'Displayed Text')?? Mathworks could define their version of fprintf to use 3 as command window and thus fprintf(3,'Displayed Text') would work.

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David Brown
David Brown on 20 Apr 2017
To all,
This is kind of an old thread but I ran into the same problem and found a solution that works for me. Yair Altman created a function called cprintf that can be used instead of fprintf to print colored text to the command window. I tried cprintf with R2014a in a block callback and it sent the text to the command window. I haven't tried later versions of Matlab but I suspect that it works in later releases as well. To make it look like fprintf just use 'black' as the first parameter.
The cprintf utility is available through the FEX here:
Thanks Yair.

Mohamed Elattal
Mohamed Elattal on 7 Jul 2017
Edited: Mohamed El-Attal on 7 Jul 2017
Just migrated to 2016b. This is quite an annoying change!!! disp has been there since forever and changing its behaviour from model callback without a backward compatibility variant is completely unjustified!!
fprintf(2,..) doesn't do the trick.
Text is in red except the last character!
Text is displayed before the command input >>
Warning and error messages are displayed in diagnostics viewer, so information is again split.
  1 Comment
Stefanie Schwarz
Stefanie Schwarz on 3 Jul 2019
If you add a newline escape sequence (\n), the entire text will be red and ">>" appears in a new line:
fprintf(2, 'Test message.\n');

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Michael on 31 Aug 2017
This is really an annoying change! Give us disp directed to the command window for simulink callbacks back!

Mark Mears
Mark Mears on 21 Oct 2017
Old thread... still annoying... still not addressed anywhere I can find. Is there any other way to use "disp" to print results to the command window? Is there some other way to have Simulink callbacks help output data?



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