MATLAB: Do I get a runtime error when I use the NEQ function in the MATLAB C++ Math Library

Question

Why do I get a runtime error when I use the NEQ function in the MATLAB C++ Math Library?

The following code, "example.cpp", reproduces this problem:

#include "matlab.hpp"
#include <stdlib.h>     /* used for EXIT_SUCCESS */
static double xdata[] = { 1,2,3,4,5,6,7,8 };
int main(int argc, char* argv[])
{
          mwArray temp1(2,4,xdata);
          mwArray temp2(2,4,xdata);
          mwArray z = zeros(2,4);;
//     z = eq(temp1,temp2);    // this works ok        
          z = neq(temp1,temp2);   // this is BROKEN
//     z = temp1 != temp2;             // this works ok
//     z = temp1 == temp2;             // this works ok
          cout <<"z: "<<z << endl;
          return 0;
}

To compile and run this in MATLAB, I used the following command:

mbuild example.cpp
!example

With the code above, I would get a runtime error. However if I uncomment any other line and comment the line using NEQ, i.e.

          z = eq(temp1,temp2);    // this works ok        
//     z = neq(temp1,temp2);   // this is BROKEN
//     z = temp1 != temp2;             // this works ok
//     z = temp1 == temp2;             // this works ok

The program executes correcty.

Answer 1

This is a bug in the MATLAB C++ Math Library. This has been brought to the attention of our development staff to be addressed in a future version of the C++ Math Library.

As a workaround, please use the "!=" operator for not equals instead of the functional form.