MATLAB: Error C2079: ‘pm’ uses undefined struct ‘mxArray_tag’

Question

I am clearly missing something silly here because I get the compiler error C2079: 'pm' uses undefined struct 'mxArray_tag'

#include <math.h>
#include <string.h>
#include <iostream>
#include "mex.h"
#include "matrix.h"
void sample(mxArray* X,mxArray* Y){
      // does nothing  
    mxArray pm;
  }

Answer 1

It should be:

mxArray* pm;

You're missing a *