Segmentation fault when calling function startMATLAB in C(++) code.

I am using Bash on Ubuntu on Windows to compile my code:

 g++ -std=c++11 -g -I ../../../../../../Program\ Files/MATLAB/R2018b/extern/include
 -L ../../../../../../Program\ Files/MATLAB/R2018b/extern/bin/win64 -pthread testMatlab.cpp
 -l:../../../../../../Program\ Files/MATLAB/R2018b/extern/lib/win64/mingw64/libMatlabDataArray.lib
 -l:../../../../../../Program\ Files/MATLAB/R2018b/extern/lib/win64/mingw64/libMatlabEngine.lib -o testMatlab.o

I'm using the test code from MATLAB:

#include "MatlabDataArray.hpp"
#include "MatlabEngine.hpp"
#include <iostream>
void callSQRT() {

   using namespace matlab::engine;
   std::cout << "1" << std::endl;
   // Start MATLAB engine synchronously
   std::unique_ptr<MATLABEngine> matlabPtr = startMATLAB(); //<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
   std::cout << "2" << std::endl;
   //Create MATLAB data array factory
   matlab::data::ArrayFactory factory;
   std::cout << "3" << std::endl;
   // Define a four-element typed array
   matlab::data::TypedArray<double> const argArray =
       factory.createArray({ 1,4 }, { -2.0, 2.0, 6.0, 8.0 });
   std::cout << "4" << std::endl;
   // Call MATLAB sqrt function on the data array
   matlab::data::Array const results = matlabPtr->feval(u"sqrt", argArray);

   // Display results
   for (int i = 0; i < results.getNumberOfElements(); i++) {
       double a = argArray[i];
       std::complex<double> v = results[i];
       double realPart = v.real();
       double imgPart = v.imag();
       std::cout << "Square root of " << a << " is " <<
           realPart << " + " << imgPart << "i" << std::endl;
   }
}

int main() {
   callSQRT();
   return 0;
}

But I get a segmentation fault at the line "std::unique_ptr<MATLABEngine> matlabPtr = startMATLAB();"

Any ideas as to what my issue is?

Thanks.

[Vincent Huber]

To compilte my mex function I had to link against

• libMatlabEngine
• libMatlabDataArray
• libmx
• libmat
• libmex
• libut

You'll see with ldd that libMatlabEngine requires some symbols in the others libs

Answer 1

[Agah Karakuzu]

I am having the exact same issue!

Answer 2

[Abhishek Singh]

Hi Matthew,

There are couple of things you need to ensure; first ensure compiler you’re using is supported for use with MATLAB, use this link for the same:

https://www.mathworks.com/support/compilers.html

On Linux you can use the following commands to know about your compiler:

gcc -v
g95 -v
g77 -v

If this is correct, then check if you’ve set up the build and runtime environment correctly. Use this link to ensure the same:

https://www.mathworks.com/help/matlab/matlab_external/build-c-engine-programs.html

I hope this would solve the issue