C++ Access violation exception when calling Matlab compiled function: null pointer mistake? - c++

Question

I've searched extensively but there seems not to be a satisfying answer to this question online. So I'm posting again this problem in case someone has found a solution.
I have written a C++ code that is supposed to call some Matlab code. I have compiled all my Matlab files using the following command:
mcc -N -W cpplib:libRTR2 -T link:lib RTR.m -v
I have included the header, DLL and LIB files created by above command in the 'Header Files'for my Visual Studio project. I have also includde mclmcrrt.lib, mclmcrrt.h and mclcppclass.h in the same.
Here is my C++ code:
#define BZZ_COMPILER 3
#include <stdint.h>
#include "./hpp/BzzMath.hpp"
#include "libRTR2.h"
#include <iostream>
#include "mclmcrrt.h"
#include "mclcppclass.h"
double RTRtest(BzzVector &x)
{
x(1);
mwArray out(1,1);
try {
// create input
double a[] = { x[1] };
mwArray in1(1, 1, mxDOUBLE_CLASS, mxREAL);
in1.SetData(a, 1);
// call function
RTR(1, out, in1);
// show result
std::cout << "objFun" << std::endl;
std::cout << out << std::endl;
double F[1];
out.GetData(F, 1);
for (int i = 0; i<1; i++) {
std::cout << F[i] << " " << std::endl;
}
}
catch (const mwException& e) {
std::cerr << e.what() << std::endl;
return -2;
}
catch (...) {
std::cerr << "Unexpected error thrown" << std::endl;
return -3;
}
// cleanup
return out;
}
int optim()
{
if (!mclInitializeApplication(NULL, 0)) {
std::cerr << "could not initialize the application" << std::endl;
mclGetLastErrorMessage();
return -1;
}
if (!libRTR2Initialize()) {
std::cerr << "Could not initialize the library" << std::endl;
return -1;
}
bzzFilePrint("BzzRobustMinimization.txt");
BzzVector Xmin(1, 2000.);
BzzVector Xmax(1, 5000.);
BzzVector X0(1, 2000.);
double F0 = RTRtest(X0);
BzzMinimizationRobust m(X0, F0, RTRtest, Xmin, Xmax);
m();
m.BzzPrint("Results");
libRTR2Terminate();
mclTerminateApplication();
}
int main()
{
mclmcrInitialize();
return mclRunMain((mclMainFcnType)optim, 0, NULL);
}
And when I try to debug it I obtain this error:
Access Violation Error
I know it is related probably to trying to pass a null pointer to one of my functions, but being no expert in C++ I'm struggling to find where the error lies. Any help is greatly appreciated!