passing a 3D array of shorts as an argument to a c function from C#

c#
using System;

using System.Runtime.InteropServices;

public class Tester
{
    [DllImport("test.so", EntryPoint="process_3d_array")]
    public static extern uint test(IntPtr grid, int width, int length, int height );


    public static int height = 20 ,width = 20 , length = 5;

    
    public static short[,,] testArr = new short[height,width,length];

    public static void Main(string[] args)
    {

        try
            {
                    unsafe
                        {
                        fixed (short* pArray = testArr)
                        {
                                IntPtr arr = (IntPtr)pArray;
                                test(arr, width, length, height);
                        }
                    }
            }
            catch (Exception ex)
            {
                    Console.WriteLine("Exception occurred: " + ex.Message);
            }


        for(int i = 0 ; i < length ;i++){
            for(int j = 0 ; j < width ; j++){
                Console.Write(testArr[0,i,j]);
            }
            Console.WriteLine();
        }
    }

}

c#
using System;

using System.Runtime.InteropServices;

public class Tester
{
    [DllImport("test.so", EntryPoint="process_3d_array")]
    public static extern uint test(IntPtr grid, int width, int length, int height );


    public static int height = 20 ,width = 20 , length = 5;

    
    public static short[,,] testArr = new short[height,width,length];

    public static void Main(string[] args)
    {

        try
            {
                    unsafe
                        {
                        fixed (short* pArray = testArr)
                        {
                                IntPtr arr = (IntPtr)pArray;
                                test(arr, width, length, height);
                        }
                    }
            }
            catch (Exception ex)
            {
                    Console.WriteLine("Exception occurred: " + ex.Message);
            }


        for(int i = 0 ; i < length ;i++){
            for(int j = 0 ; j < width ; j++){
                Console.Write(testArr[0,i,j]);
            }
            Console.WriteLine();
        }
    }

}

#include <stdio.h>
int process_3d_array(short*** grid, int width, int length, int height ){

    printf("first statement\n");

    for(int i = 0 ; i < height ; i++){
        for(int j = 0  ; j < length; j++){
            for(int k = 0 ; k < width ; k++){
                grid[i][j][k] = i*j*k;
            }
        }
    }

    printf("second statement\n");
    return 0;
}

#include <stdio.h>
int process_3d_array(short*** grid, int width, int length, int height ){

    printf("first statement\n");

    for(int i = 0 ; i < height ; i++){
        for(int j = 0  ; j < length; j++){
            for(int k = 0 ; k < width ; k++){
                grid[i][j][k] = i*j*k;
            }
        }
    }

    printf("second statement\n");
    return 0;
}

first statement

first statement