How to open .dll file in MATLAB. I have converted the .slx file to .dll file format. Now I want to open and see the results. I don't have any header file which I can use with the function "loadlibrary"

I have .dll file which I want to open and run in MATLAB. What is the procedure, please suggest.

Answer 1

[Kojiro Saito]

For C shared library, you can load the dll by loadlibrary and call functions by calllib.

For detail, please see this document.

https://www.mathworks.com/help/matlab/ref/loadlibrary.html

For C++ shared library, you need to do addpath in order to set your dll file to MATLAB's search path and you can call functions by clib.libname.funcname.

For detail, please see this document.

https://www.mathworks.com/help/matlab/matlab_external/call-functions-in-cpp-shared-library.html

For .NET assembly, you can load the dll by NET.addAssembly and call functions by like this.

 asm = NET.addAssembly('your.dll');
 
 cls = dotNetTestClass.TestClass; % dotNetTestClass is namespace and TestClass is class in C#
 a = 1; % Input 1
 b = 2; % Input 2
 result = TestFunc(cls, a, b); % TestFunc is function name in C#
 

For detail, please see this document.

https://www.mathworks.com/help/matlab/ref/net.addassembly.html

If the dll is created from .slx using Embedded Coder, you need to do an additional step as described in the following answer.

https://www.mathworks.com/matlabcentral/answers/103457

[Krutika Shetkar]

Hi Kojiro,

Thank you for the update.

I followed the steps suggested in the above link. I am getting an error "A 'Selected' compiler was not found. You may need to run mex -setup."

Attaching the screenshot for reference. Kindly suggest.

[Walter Roberson]

What problem did you encounter when you gave the command

mex -setup

after having installed a supported compiler?

[Krutika Shetkar]

Getting some warning as "Warning: The library class 'controller_win64' already exists. Use a classname alias.

> In loadlibrary at 180 "

Attaching screenshot for reference.

[Kojiro Saito]

If the warinng "Warning: The library class 'controller_win64' already exists. Use a classname alias. " occurs, you need to unload the library first.

unloadlibrary('controller_win64')

Did you try adding icludepath?

model_name = 'controller';
dll_name = [model_name, '_' computer('arch')];

loadlibrary(dll_name, [model_name, '_ert_shrlib_rtw', filesep, model_name, '.h'],...
   'includepath', [model_name, '_ert_shrlib_rtw'],...
   'includepath', fullfile(matlabroot,'simulink','include'));

If loadlibrary gets an error saying that "To load an Embedded Coder Shared Library, use coder.loadlibrary

instead of calling loadlibrary directly.", use coder.loadlibary instead.

coder.loadlibrary(dll_name, [model_name, '_ert_shrlib_rtw', filesep, model_name, '.h'],...
'includepath', [model_name, '_ert_shrlib_rtw'],...
'includepath', fullfile(matlabroot,'simulink','include'));

[Krutika Shetkar]

Hi Kojiro,

Thanks for the update.

When tried to unload and load back the library got this warning "Warning: Warnings messages were produced while parsing. Check the functions you intend to use for correctness. Warning text can

be viewed using:

[notfound,warnings]=loadlibrary(...)

> In loadlibrary at 343 "

And when tried to include path, it is not identifying the file, even though its in the same folder, getting error "Error using loadlibrary>lFullPath (line 598)

Could not find file controllercontroller_ert_shrlib_rtw\controllercontroller.h."

[Krutika Shetkar]

Please suggest

[Kojiro Saito]

You have an error in doing loadlibrary due to the wrong file path, so unloadlibrary also gets an error because the library was not loaded. controller_ert_shrlib_rtw is correct folder path, but you're specifying controllercontroller_ert_shrlib_rtw.

Here is script which specifying the proper path.

loadlibrary('controller_win64', ['controller_ert_shrlib_rtw', filesep, 'controller.h'],...
   'includepath', 'controller_ert_shrlib_rtw',...
   'includepath', fullfile(matlabroot,'simulink','include'));

If the above gets an error, please use coder.loadlibrary instead.

coder.loadlibrary('controller_win64', ['controller_ert_shrlib_rtw', filesep, 'controller.h'],...
   'includepath', 'controller_ert_shrlib_rtw',...
   'includepath', fullfile(matlabroot,'simulink','include'));

[Krutika Shetkar]

Hi Kojiro,

The same warning error repeats even after trying the above solution.

Warning " Warnings messages were produced while parsing. Check the functions you intend to use for correctness. Warning text can be

viewed using:

[notfound,warnings]=loadlibrary(...) "

[Kojiro Saito]

As the message suggest, could you call loadlibrary with two outputs?

[notfound,warnings]=loadlibrary('controller_win64', ['controller_ert_shrlib_rtw', filesep, 'controller.h'],...
   'includepath', 'controller_ert_shrlib_rtw',...
   'includepath', fullfile(matlabroot,'simulink','include'));

warnings variable should contain what is the actual error in the header (.h) file.

From this answer, this warning occurs when doing loadlibrary with C++ header file not pure C.

[Kojiro Saito]

@Krutika Shetkar

>Hi Kojiro,

>I have successfully loaded the dll library. Can you suggest me how to test the file like how I can run the file >and check the output in simulink/MATLAB.

As described in my first answer, libfunctions and calllib will be used for C shared dll. It depends on your model, but you can find which functions should be called by the following.

libfunctions('controller_win64')

or,

libfunctionsview 'controller_win64'

Possibly, controller_win64_initialize, controller_win64_terminate and controller_win64_step will be found.

You can call these functions by

calllib('controller_win64', 'controller_win64_initialize')
calllib('controller_win64', 'controller_win64_step')
calllib('controller_win64', 'controller_win64_terminate')

I'm not sure your controller model, but if your model requires some input, you need to add input arguments in calllib like, calllib('controller_win64', 'controller_win64_step', input1, input2, ...).

For detail, please read the following documents.

https://www.mathworks.com/help/matlab/ref/libfunctions.html

https://www.mathworks.com/help/matlab/ref/libfunctionsview.html

https://www.mathworks.com/help/matlab/ref/calllib.html

[Krutika Shetkar]

Hi Kojiro,

Is there any solution where I can run the dll file in simulink? Can you suggest me how to run the dll file in simulink to check the results.

[Kojiro Saito]

There are various ways to do that and here is a link to File Exchange page which describes them.

https://www.mathworks.com/matlabcentral/fileexchange/44197

Answer 2

[Krutika Shetkar]

Hi Kojiro,

I have successfully loaded the dll library. Can you suggest me how to test the file like how I can run the file and check the output in simulink/MATLAB.