S-Function 'ExampleFunction' does not exist

Hello,

I am facing an error that completely puzzles me. Let's have the following scenario:

I copy the sfun_counter_cpp.cpp from the Matlab examples folder into another directory. In the same directory I create a Simulink Model with an S-Function calling the cpp file. Everyhing works. Now I do the same as before, but now I rename the file to 'sfun_test_cpp.cpp' and every encounter of the expression 'sfun_counter_cpp' in the file to 'sfun_test_cpp'. I also edit the S-Function accordingly and now... 'sfun_test_cpp' doesn't exist!

I am trying to debug this error for more than 2 hours now. What the heck is wrong here?

Answer 1

[Anay]

Hi Vincent,

In order to use C++ S-functions you must compile them into MEX files. The error “<file name> doesn't exist!” means that the MEX file with the same name is missing, not the CPP file.

You must use the following command to compile your CPP file to MEX file:

mex sfun_test_cpp.cpp 

This should solve the error of missing file.

You can consider following below links to learn more about basics of S-functions and MEX files:

• https://www.mathworks.com/help/releases/R2024b/simulink/s-function-basics-matlab.html
• https://www.mathworks.com/help/releases/R2024b/matlab/ref/mex.html