Title: Not found or invalid function error
Last modified: August 20, 2016

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# Not found or invalid function error

 *  Resolved [Neil](https://wordpress.org/support/users/ademmeda/)
 * (@ademmeda)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/)
 * Hi,
 * I started developing a plugin from scratch and I have a small problem with my
   setup.
 * Firstly, here is the error I am getting:
 * Warning: call_user_func_array() expects parameter 1 to be a valid callback, function‘
   my_function’ not found or invalid function name in C:\…\wp-includes\plugin.php
   on line 405
 * And here is my code:
 *     ```
       add_action( 'admin_menu', array( 'my_plugin', 'menu' ) );
   
       class my_plugin {
   
       	function menu() {
       		if ( current_user_can( 'manage_options' ) ) {
       			add_menu_page( 'Settings', 'Settings', 'manage_options', 'my-plugin', 'my_function' );
       		}
       	}
   
       	function my_function() {
       		include 'inc/settings.php';
       	}
       }
   
       $my_plugin = new my_plugin;
       ```
   
 * I am new to PHP classes and I can’t see what is wrong.
 * Thanks for any ideas.

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [Jeffrey](https://wordpress.org/support/users/h0tw1r3/)
 * (@h0tw1r3)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/#post-2584988)
 * There are a couple problems.
 * 1. `add_menu_page` expects a single argument for the function (you’re using two).
   Should be `array(class,function)` or just `function`.
    2. you instantiate the
   class, but then hook to the static methods.
 * I would also suggest that if you’re going to wrap your plugin in a class, keep
   everything (ie. `add_action`) inside the class.
 * Here’s a quick suggestion, hope it helps.
 *     ```
       class my_plugin {
   
               function __construct() {
                   add_action( 'admin_menu', array( &$this, 'menu' ) );
               }
   
       	function menu() {
       		if ( current_user_can( 'manage_options' ) ) {
       			add_menu_page( 'Settings', 'Settings', 'manage_options', array( &$this, 'my_function') );
       		}
       	}
   
       	function my_function() {
       		include 'inc/settings.php';
       	}
       }
   
       $my_plugin = new my_plugin;
       ```
   
 *  Thread Starter [Neil](https://wordpress.org/support/users/ademmeda/)
 * (@ademmeda)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/#post-2584993)
 * Hi,
 * Thanks for the reply, “$this” didn’t work and I found the answer on [http://codex.wordpress.org/Function_Reference/add_submenu_page](http://codex.wordpress.org/Function_Reference/add_submenu_page)
 * Now I have
 * `add_menu_page( 'Plugin Settings', 'Settings', 'manage_options', 'plugin-slug',
   array( __CLASS__, 'settings' ) );`
 * and it works.
 * Sorry, I am new to all this, what does “you instantiate the class, but then hook
   to the static methods.” mean? Why should I keep everything in the plugin class?
   What problems could happen?
 * Thanks a lot.
 *  [Jeffrey](https://wordpress.org/support/users/h0tw1r3/)
 * (@h0tw1r3)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/#post-2584995)
 * $this does work, but only when you use the complete code I provided.
 * There are no downsides to how you are writing your class. I’m simply stating 
   you will run into troubles until you understand the [basics of OOP in PHP](http://www.php.net/manual/en/language.oop5.basic.php).
   Pay particular attention to scoping.
 *  Thread Starter [Neil](https://wordpress.org/support/users/ademmeda/)
 * (@ademmeda)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/#post-2584998)
 * Thanks for the link, I guess I should have started learning from that page.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Not found or invalid function error’ is closed to new replies.

## Tags

 * [class](https://wordpress.org/support/topic-tag/class/)

 * In: [Hacks](https://wordpress.org/support/forum/plugins-and-hacks/hacks/)
 * 4 replies
 * 2 participants
 * Last reply from: [Neil](https://wordpress.org/support/users/ademmeda/)
 * Last activity: [14 years, 1 month ago](https://wordpress.org/support/topic/not-found-or-invalid-function-error-1/#post-2584998)
 * Status: resolved

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