Relation between .dll files and S-functions?

Hi everybody,

I am trying to run an old Simulink model created in 2009 in MATLAB R2012b. The model has two S-functions.

When running it, it gives the following error message: "Error in S-function 'ABS_Truck_debug/ABS Subsystem/S-ABS': S-Function 'abs_tractor' does not exist"

The folder with the model files also contains two .dll files with the same names as the missing S-functions. But Simulink doesn’t accept the .dll as S-functions. Could it be because I am running a newer version of Matlab/Simulink where S-functions are defined in a different manner (I have very little knowledge in S-functions)?

Any clues regarding this are very welcome.

Kind regards,

Johan Skov Bergholt

Student at University of Aarhus, Denmark

Answer 1

[Kaustubha Govind]

Note that since R14SP3, the .dll extension is no longer used for MEX-files in MATLAB (see here). MEX-files now have platform-specific extensions like .mexw32 and .mexw64. The older .dll files were phased out when MATLAB only had 32-bit support, so it is likely that your S-functions are 32-bit binaries that were compiled on an old version of MATLAB. If you are now using 64-bit MATLAB, you cannot use 32-bit binaries on it. You need to either recompile the MEX-files, or try installing 32-bit MATLAB on your 64-bit machine. See: Is running 32-bit MATLAB on a 64-bit platform supported?

[Johan Skov Bergholt]

Hi Kaustubha,

Thank you for your answer!

From your link:

http://www.mathworks.se/help/matlab/matlab_external/running-mex-files-with-dll-file-extensions-on-windows-32-bit-platforms.html

Is it correctly understood that I need to install the version 32-bit MATLAB R2008b or earlier in order for it to have .dll support? Or will 32-bit R2012b also have that?

Regards, Johan