prepared statement - What is the difference between the following to methods for bind_param PHP -

i'm getting on using singleton approach , starting prepared statements... i'm racking brain on why 1 version of works , 1 not when, me, seem same thing... want work second way in order meet end goal.

this works:

call_user_func_array(array($stmt, 'bind_param'), array("i", 2)); 

this not:

$params = array("i", 2); call_user_func_array(array($stmt, 'bind_param'), $params); 

you getting error message like

mysqli_stmt::bind_param() expected reference, value given in...

the problem bind_param() in php 5.3+ requires array values reference while 5.2 works real values.

from docs:

care must taken when using mysqli_stmt_bind_param() in conjunction call_user_func_array(). note mysqli_stmt_bind_param() requires parameters passed reference, whereas call_user_func_array() can accept parameter list of variables can represent references or values (ref).

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one solution create array of references

$params = array("i", 2); $tmp = array(); foreach($params $key => $value) {     $tmp[$key] = &$params[$key]; } call_user_func_array(array($stmt, 'bind_param'), $tmp);  

and similar solution is

function refvalues($arr){      if (strnatcmp(phpversion(),'5.3') >= 0) //reference required php 5.3+      {          $refs = array();          foreach($arr $key => $value)              $refs[$key] = &$arr[$key];          return $refs;      }      return $arr;  }   $params = array("i", 2); call_user_func_array(array($stmt, 'bind_param'), refvalues($params));