mysqli bind_param() expected to be a reference, va

Question

Can't figure out, whats causing error Parameter 3 to mysqli_stmt::bind_param() expected to be a reference, value given in...

PDO
$query = "INSERT INTO test (id,row1,row2,row3) VALUES (?,?,?,?)";
$params = array(1,"2","3","4");
$param_type = "isss";
$sql_stmt = mysqli_prepare ($mysqli, $query);
call_user_func_array('mysqli_stmt_bind_param', array_merge(array($sql_stmt, $param_type), $params));
mysqli_stmt_execute($sql_stmt);

Also tried OOP

OOP
$insert_stmt = $mysqli->prepare($query);
array_unshift($params, $param_type);
call_user_func_array(array($insert_stmt, 'bind_param'), $params);
$insert_stmt->execute();

But same error, only that now Parameter 2 is causing problem.

So, what's wrong with $params? I need $params to be an array of values.

Answer 1

UPDATE

This answer is outdated. Please use the spread operator in newer PHP versions like answered by Stacky.

From php docu:

Care must be taken when using mysqli_stmt_bind_param() in conjunction with call_user_func_array(). Note that mysqli_stmt_bind_param() requires parameters to be passed by reference, whereas call_user_func_array() can accept as a parameter a list of variables that can represent references or values.

And on the page mysqli-stmt.bind-param you have different solutions:

For example:

call_user_func_array(array($stmt, 'bind_param'), refValues($params));

function refValues($arr){
    if (strnatcmp(phpversion(),'5.3') >= 0) //Reference is required for PHP 5.3+
    {
        $refs = array();
        foreach($arr as $key => $value)
            $refs[$key] = &$arr[$key];
        return $refs;
    }
    return $arr;
}

Answer 2

Dunno why word 'PDO' in the code but that's the only right word in it. Use PDO, and face not a problem you have with mysqli prepared statements:

$query = "INSERT INTO test (id,row1,row2,row3) VALUES (?,?,?,?)";
$params = array(1,"2","3","4");
$stmt = $pdo->prepare($query);
$stmt->execute($params);

Just look at this clean and concise code and compare it with one you need with mysqli prepared statements.

Answer 3

Introduced in PHP 5.6, you can use the ... operator ("spread operator") to achieve the same result with less trouble:

//object-oriented
$sql_stmt->bind_param($param_type, ...$params);

//procedural
mysqli_stmt_bind_param($sql_stmt, $param_type, ...$params);