How can I unload an automatically generated .dll file?

I am using a FMU (generated from Dymola 2018) in a Simulink model. When the model is compiled, a .dll file is created (among others). Now if I want to compile the model again, I receive warning that this file cannot be overwritten. I cannot delete the file manually because the file is in use. Using

version -modules

I can see that the .dll file is loaded in MATLAB, even after closing the model.

After searching the depths of the Internet I have tried several solutions, none of which work, including:

bdclose('all')
clear all, clear classes, clear mex

As the .dll isn't a .mex file, I cannot use the mislocked or munlock functions. The function

unloadlibrary

also doesn't work, as the generated .dll does not have an accompanying header.

Deleting the file using the Windows command

delete /f file.dll

doesn't work either, nor does manually unregistering the .dll using

regsvr32 /u file.dll

The only way I can delete the file at the moment is to close MATLAB. Is this a common problem with imported FMU's? Why doesn't MATLAB unload the .dll automatically when the model is closed? Is there a way to force MATLAB to unload the .dll?

[IronLikeABrian]

Hello I'm having the same problem. Is there anybody who has some suggestion?

[Marcus Arndt]

@IronLikeABrian:

I eventually solved the problem by switching to OpenModelica. I must admit, it's not quite as comfortable as Dymola, but it's free and this specific problem doesn't occur.

Word of warning: it did, however, take me a while to calibrate the initial conditions of the model; it seems OpenModelica is not as forgiving as Dymola.

Sorry that I can't provide an answer that actually solves the problem, but I hope I could still help.

Answer 1

[Fangjun Jiang]

try "clear functions"?