help with understanding call_user_func_array and & reference operator

azegurb

<?php

function read()
{
   $parameters = array();
   $results = array();

   $mysql = new mysqli('localhost', 'root', 'root', 'db') or die('There was a problem connecting to the database');
   $stmt = $mysql->prepare('SELECT body FROM posts') or die('Problem preparing query');
   $stmt->execute();

   $meta = $stmt->result_metadata();

   while ( $field = $meta->fetch_field() ) {

 $parameters[] = &$row[$field->name];
   }

   call_user_func_array(array($stmt, 'bind_result'), $parameters);

   while ( $stmt->fetch() ) {
      $x = array();
      foreach( $row as $key => $val ) {
         $x[$key] = $val;
      }
      $results[] = $x;
   }

   return $results;

}

$results = read();
?>
<!DOCTYPE html>

<html lang="en">
<head>
   <meta charset="utf-8">
   <title>untitled</title>
</head>
<body>
<?php foreach ($results as $row) : ?>

   <p> <?php echo $row['body']; ?> </p>
<?php endforeach; ?>
</body>
</html>

vicodin

Read this, its a good explanation of that function.

http://www.unemployeddeveloper.com/239_lesser-known-php-functions-call_user_func_array/

azegurb

thank you for attention. but can you explain it on my code
original source is
http://net.tutsplus.com/tutorials/ph...ed-statements/
i tested it. i want to know what happens there

NogDog

   while ( $field = $meta->fetch_field() ) {

 $parameters[] = &$row[$field->name];
   }

That piece is creating two arrays with the same number of elements, where $parameters is numerically indexed but $row is associative using the field names as keys. Since the =& operator is used, each corresponding array element references the same value, which will initially be null. ($parameters[0] references $row['body'] in this case.)

$parameters is then used as the 2nd arg to call_user_func_array(), as it wants the supplied array to be numerically indexed. Each element of $parameters then becomes a bound parameter for the bind_result function called by the call_user_func_array(). Since the elements of $row are references to the same values, $row is then used in the while(fetch) loop so that the field names can be gotten from its array keys instead of the numerical indexes in $parameters.

azegurb

Thank you very much. now i understood the reference operator why used here
Thanks again very much