PHP mysqli_fetch_lengths() Function

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

$sql="SELECT * FROM Persons ORDER BY Lastname";

if ($result=mysqli_query($con,$sql))
  {
  $row=mysqli_fetch_row($result);

  // Display field lengths
  foreach (mysqli_fetch_lengths($result) as $i=>$val)
    {
    printf("Field %2d has length: %2d\n",$i+1,$val);
    }

  // Free result set
  mysqli_free_result($result);
}

mysqli_close($con);
?>