Strict Standards Error - passing by reference

Question

I keep getting this error:

Strict Standards: "Only variables should be passed by reference in
/home/mydirectory/public_html/myfolder/modules/checkout/controllers/myfile.php
on line 65"

This is the code on line 65:

$stmt->bind_param(
  "iissds", 
  $this->auth->getInformation("id"), 
  $_POST["method"], 
  $transaction_id, 
  $Method->getTransactionID(), 
  $total_price, 
  serialize($_POST));

I did try editing my php.ini and inputting a code snippet to ignore these errors, to no avail, i may have goofed it up, as I'm fairly new to it..

If someone can show me how to strict proof it, that would be awesome! Thanks in advance

It's probably best to get a handle on the issue rather than just avoid the warning. Have you tried printing out each argument to see the values or substituting each argument? That might give you an idea of what is causing the issue. — Devon Bessemer, Nov 13 '14 at 06:54
I have no idea how to go about doing that, the only error is on line 65, that i posted there. My friend coded it up for me, and he is on holiday.. — KeRRR, Nov 13 '14 at 07:17

Mitch Satchwell · Answer 1 · 2014-11-13T08:05:49.207

I'm guessing the bind_param function you are calling is mysqli's bind_param.

If we have a look at the definition for this function we will see the variables are passed by reference:

 bool mysqli_stmt::bind_param ( string $types , mixed &$var1 [, mixed &$... ] )

(The & indicates by reference.)

Now let's look at the error you are getting:

Only variables should be passed by reference

The problem is that you are passing the results of function calls directly to bind_param, when only variables should be passed by reference.

To get around this all you need to do is assign these values to variables and pass those to the function instead, for example:

$id = $this->auth->getInformation("id");
...

$stmt->bind_param('iissds', $id, ...

For more information on references take a look at the php.net article 'What References Do':

http://php.net/manual/en/language.references.whatdo.php

Hididng Errors

In your question you mention hiding these messages. It is always better to fix problems with your code than to suppress warnings.

To adjust what errors are displayed take a look at PHP's error_reporting function.

If you wanted to show everything except strict you could do:

error_reporting(E_ALL ^ E_STRICT);

This can also be set in the php.ini configuration file:

error_reporting = E_ALL ^ E_STRICT

Or wrapping with parentheses `($this->auth->getInformation("id"))` — revo, Nov 13 '14 at 08:06

Strict Standards Error - passing by reference

1 Answers1