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Using multiple copies of the same MATLAB Function Block

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I'm trying to use the same MATLAB Function block multiple times in the same Simulink model. These duplicate instances of the MATLAB function are inside a library. I think this is a key piece of information for this issue.
If I have one copy of the block, the model compiles just fine. If I add a second MATLAB function block, identical to the first one, I get a conflicting declaration error that happens when the S-Functions are being generated for the MATLAB function blocks:
"C:\Program Files\MATLAB\R2020a\bin\win64\mex.exe" -R2018a -c -DMATLAB_MEX_FILE -I"C:\dev\Simulink\Models\controller\slprj\_sfprj\controller\lib_controller\sfun\src" -I"C:\dev\Simulink\Models\controller" -I"C:\Program Files\MATLAB\R2020a\extern\include" -I"C:\Program Files\MATLAB\R2020a\simulink\include" -I"C:\Program Files\MATLAB\R2020a\simulink\include\sf_runtime" -I"C:\Program Files\MATLAB\R2020a\stateflow\c\mex\include" -I"C:\Program Files\MATLAB\R2020a\rtw\c\src" -I"C:\dev\Simulink\Models\Controller\slprj\_sfprj\controller\lib_controller\sfun\src" CFLAGS="$CFLAGS " lib_controller_sfun.cpp Building with 'MinGW64 Compiler (C++)'. In file included from C:\dev\Simulink\Models\Controller\slprj\_sfprj\controller\lib_controller\sfun\src\c2_lib_controller.h:42:0, from C:\dev\Simulink\Models\Controller\slprj\_sfprj\controller\lib_controller\sfun\src\lib_controller_sfun.cpp:5: C:\dev\Simulink\Models\controller/interface_parameters.h:15:3: error: conflicting declaration 'typedef struct CURVE_POINT CURVE_POINT' } CURVE_POINT; ^~~~~~~~~~~ In file included from C:\dev\Simulink\Models\Controller\slprj\_sfprj\controller\lib_controller\sfun\src\c1_lib_controller.h:42:0, from C:\dev\Simulink\Models\Controller\slprj\_sfprj\controller\lib_controller\sfun\src\lib_controller_sfun.cpp:4: C:\dev\Simulink\Models\controller/interface_parameters.h:15:3: note: previous declaration as 'typedef struct CURVE_POINT CURVE_POINT' } CURVE_POINT; ^~~~~~~~~~~
How could this be prevented? I thought it was possible to use multiple instances of the same MATLAB Function block without a problem.


Leonardo Maia
Leonardo Maia on 13 Jul 2020
The error seems to originate from these includes in "library_sfun.cpp":
#include "c1_lib_controller.h"
#include "c2_lib_controller.h"
Each of these headers refers to one instance of the MATLAB Function block. Each of them has a "#include interface_parameters.h", which is where I define the structs for my model parameters. Since it's being included twice, I get this error.
How to prevent this?
Walter Roberson
Walter Roberson on 13 Jul 2020
Can you protect the code with an #ifndef ?
#ifndef interface_parameters_h
#define interface_parameters_h
then the code
Leonardo Maia
Leonardo Maia on 13 Jul 2020
All these files are generated code from the compilation of the main model, I don't think I'm supposed to edit them.

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Accepted Answer

Leonardo Maia
Leonardo Maia on 13 Jul 2020
Fixed the issue by encapsulating the MATLAB Function block in a subsystem in the library.


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