Only variables can be passed by reference - php

问题

i am trying this code, but i get this error:

Only variables can be passed by reference in xxx

script

class page {
  function insert($db, $of, $form, &$arr) {

      $i = 0;

      foreach(array_combine($form['value0'], $arr) as $val=>$v){

          $sql->prepare("mysqli query here");
          $sql->bind_param('ssss', $val, $of, $v[$i][0], $v[$i][1]);//error here
          $sql->execute();
          $i++;

      }
      return true;
  }
}

what is the reason, and how can be solved ? thanks

回答1:

I assume you're using mysqli::bind_param. All arguments except the first are passed by reference. This means they must be variables, and not strings, array elements, etc. I'm actually not sure why it needs to do this by reference, but never mind. You can fix it pretty easily:

$v0 = $v[$i][0];
$v1 = $v[$i][1];
$sql->bind_param('ssss', $val, $of, $v0, $v1);

来源：https://stackoverflow.com/questions/7911096/only-variables-can-be-passed-by-reference-php