I have a C++ code opening a file and rewriting the file and I want to execute the function thro MATLAB

As I mentioned, I am now having a C++ code opening a file and rewriting the content, and I want to use mex.h to call the function in MATLAB.

for example, I have:

   void Write_File(){
      ofstream file("abc.txt");
      double X=0;
      file << setw(12) << 0.0 << "  " << setw(12)<< X << endl;
      return 0;
   }

and now I want to do that in MATLAB. How should I define the mexFunction? what are the arguments, say nlhs, nxArray?

[James Tursa]

Why is your void function returning a value?

Answer 1

[James Tursa]

If you have no inputs or outputs, you can simply create this file:

// writefile.cpp
#include "mex.h"
// add any other supporting code here
void Write_File()
{
    ofstream file("abc.txt");
    double X=0;
    file << setw(12) << 0.0 << "  " << setw(12)<< X << endl;
}
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    Write_File();
}

Mex it at the MATLAB command line with:

mex writefile.cpp

If you get an interactive prompt asking about compilers, enter Y (have MATLAB look for them) and then select a C++ compiler from the list. Note that the LCC compiler that ships with MATLAB is strictly a C compiler, not a C++ compiler.

Call it just like any other MATLAB function:

writefile