php call to undefined function from within a class

Question

So, I have a class and from within a function in the class I am trying to call a global function, but I get the error message:

Fatal error: Call to undefined function ()

the line number the above function refers to is the line in which:

return get_session_user_id(session_id());

occurs on in the below class function

Class Ref {
    function treat_var( $var , $table ) { global $link;
    // do stuff
    return get_session_user_id(session_id());
    }
}

The treat_var function is a method in a class and is called by means of:

$ref = new Ref;
$ref->treat_var($var,$table);

The get_session_user_id function is a global function defined in an included in a file of functions and works just fine outside of the class and its code consists of:

// this function calls a USER_ID *IF one exists* from a session by using the session ID
function get_session_user_id($sessionID) { global $link;
        $result = mysqli_query($link, "SELECT USER_ID AS ID from AAB_SESSIONS WHERE PHPSESSID = '$sessionID'");
        $r = mysqli_fetch_object($result);
        return $r->ID;
}

How do I call that function from within the class?

Please include more code. This part seems to be fine. What line is the code in? — Andrius
– Andrius, Commented Nov 14, 2015 at 11:41
All the other code functions properly, if I return a string instead of the value derived from the function it returns the string and everything is happy. Still need more code? — Jeff
– Jeff, Commented Nov 14, 2015 at 11:45
I have just expirenced the very same problem with following code inside class function: $emailAddresses = array_column($recipients, 'email'); Error is: Call to undefined function MyPackage\array_column() — gandra404
– gandra404, Commented Sep 7, 2016 at 9:20

gandra404 · Accepted Answer · 2016-09-07 09:49:44Z

2

Assure that this global file where function get_session_user_id() is defined is loaded before class Ref is loaded.

In other words class loading should go in this way:
1. Include global file which contains impl of get_session_user_id()
2. Load class Ref

To check what is going on add this inside the Ref.php before the class definition

if (!function_exists('get_session_user_id')) {
    die('GLOBAL FILE NOT LOADED and get_session_user_id() function not available!!!');
}

answered Sep 7, 2016 at 9:49

gandra404

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1 Comment

Jeff Over a year ago

Thanks Gandra, I like this because rather than having to 'require_once' in several files, I address the root cause of the issue which is the fact that the function is not defined until after the class definition.

Nick · Accepted Answer · 2015-11-14 12:11:49Z

0

If you trying to call get_session_user_id() and this function is undefined, check, what file with this function is undefined, try to write

require_once "...filename with get_session_user_id() function...";

at begin of file with your class Ref.

answered Nov 14, 2015 at 12:11

Nick

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