How to test C code generated using MATLAB Coder

Hi, I converted the code from matlab central https://in.mathworks.com/matlabcentral/fileexchange/6879-fast-walsh-hadamard-transform to C code using MATLAB Coder.

Now I need to test and compile this code.

/*
 * File: fwt1d.c
 *
 * MATLAB Coder version            : 2.6
 * C/C++ source code generated on  : 09-Mar-2020 22:05:51
 */

/* Include files */
#include "rt_nonfinite.h"
#include "fwt1d.h"
#include "fwt1d_emxutil.h"

/* Function Declarations */
static void bitrevorder(const double X_data[], const int X_size[2],
  emxArray_real_T *R);
static int div_s32_floor(int numerator, int denominator);


/*
 * The function implement the 1D sequency(Walsh)ordered
 *  fast Walsh-Hadamard transform,
 *  This algorithm is implemented in N log2 N additions and subtractions.
 *  Data sequence length should be an integer power of 2.
 *  Otherwise last elements will be truncated.
 *  The inverse transform is the same as the forward transform
 *  except for the multiplication factor N.
 *
 *  Example:
 *  x=[1 2 1 1]
 *  y=fhtseq(x)
 *
 *  Author: Gylson Thomas
 *  e-mail: [e-mail]
 *  Asst. Professor, Electrical and Electronics Engineering Dept.
 *  MES College of Engineering Kuttippuram,
 *  Kerala, India, February 2005.
 *  copyright 2007.
 * Arguments    : const double data_data[]
 *                const int data_size[2]
 *                emxArray_real_T *x
 * Return Type  : void
 */
void fwt1d(const double data_data[], const int data_size[2], emxArray_real_T *x)
{
  int N;
  double k1;
  double k2;
  double k3;
      double fdbl;
  int eint;
  double L1;
  int b_x;
  int i3;
  double i;
  double j;
  double temp1;
  double temp2;

  /* ------------------------------------------------------- */
  /* 1D sequency(Walsh)ordered Fast Walsh-Hadamard Transform */
  /* ------------------------------------------------------- */
  bitrevorder(data_data, data_size, x);
  N = x->size[1];
  k1 = x->size[1];
  k2 = 1.0;
  k3 = (double)x->size[1] / 2.0;
  if (x->size[1] == 0) {
    fdbl = rtMinusInf;
  } else {
    fdbl = frexp(x->size[1], &eint);
    if (fdbl == 0.5) {
      fdbl = (double)eint - 1.0;
    } else {
      fdbl = log(fdbl) / 0.69314718055994529 + (double)eint;
    }
  }

  for (eint = 0; eint < (int)fdbl; eint++) {
    /*  In-place iteration begins here  */
    L1 = 1.0;
    for (b_x = 0; b_x < (int)k2; b_x++) {
      for (i3 = 0; i3 < (int)k3; i3++) {
        i = ((1.0 + (double)i3) + L1) - 1.0;
        j = i + k3;
        temp1 = x->data[(int)i - 1];
        temp2 = x->data[(int)j - 1];
        if ((1.0 + (double)b_x) - floor((1.0 + (double)b_x) / 2.0) * 2.0 == 0.0)
        {
          x->data[(int)i - 1] -= x->data[(int)j - 1];
          x->data[(int)j - 1] = temp1 + temp2;
        } else {
          x->data[(int)i - 1] += x->data[(int)j - 1];
          x->data[(int)j - 1] = temp1 - temp2;
        }
      }

      L1 += k1;
    }

    k1 /= 2.0;
    k2 *= 2.0;
    k3 /= 2.0;
  }

  fdbl = 1.0 / (double)N;
  eint = x->size[0] * x->size[1];
  x->size[0] = 1;
  emxEnsureCapacity((emxArray__common *)x, eint, (int)sizeof(double));
  eint = x->size[0];
  b_x = x->size[1];
  b_x *= eint;
  for (eint = 0; eint < b_x; eint++) {
    x->data[eint] *= fdbl;
  }
}

/*
 * File trailer for fwt1d.c
 *
 * [EOF]
 */

My matlab function only contains 1 argument but the generated code has 3 function arguments.

void fwt1d(const double data_data[], const int data_size[2], emxArray_real_T *x)

1. What is emxArray_real_T *x
2. How to run this code in embedded application
3. Can I test this code in MATLAB and how?