Title: Warning: call_user_func_array() expects parameter 1
Last modified: August 21, 2016

---

# Warning: call_user_func_array() expects parameter 1

 *  [sickwit](https://wordpress.org/support/users/sickwit/)
 * (@sickwit)
 * [12 years, 3 months ago](https://wordpress.org/support/topic/warning-call_user_func_array-expects-parameter-1-2/)
 * I’m getting this error on my wordpress site:
 * Warning: call_user_func_array() expects parameter 1 to be a valid callback, function‘
   livetv_do_admin_page_level_shortcode’ not found or invalid function name in /
   usr/www/lio2/public/wp-includes/plugin.php on line 470
 * Its for Live TV bundle… Please help (this error happens when i click on General
   Configuration under the admin part of my website
 *     ```
       <?php
       /**
        * The plugin API is located in this file, which allows for creating actions
        * and filters and hooking functions, and methods. The functions or methods will
        * then be run when the action or filter is called.
        *
        * The API callback examples reference functions, but can be methods of classes.
        * To hook methods, you'll need to pass an array one of two ways.
        *
        * Any of the syntaxes explained in the PHP documentation for the
        * {@link http://us2.php.net/manual/en/language.pseudo-types.php#language.types.callback 'callback'}
        * type are valid.
        *
        * Also see the {@link http://codex.wordpress.org/Plugin_API Plugin API} for
        * more information and examples on how to use a lot of these functions.
        *
        * @package WordPress
        * @subpackage Plugin
        * @since 1.5.0
        */
   
       // Initialize the filter globals.
       global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
   
       if ( ! isset( $wp_filter ) )
       	$wp_filter = array();
   
       if ( ! isset( $wp_actions ) )
       	$wp_actions = array();
   
       if ( ! isset( $merged_filters ) )
       	$merged_filters = array();
   
       if ( ! isset( $wp_current_filter ) )
       	$wp_current_filter = array();
   
       /**
        * Hooks a function or method to a specific filter action.
        *
        * WordPress offers filter hooks to allow plugins to modify
        * various types of internal data at runtime.
        *
        * A plugin can modify data by binding a callback to a filter hook. When the filter
        * is later applied, each bound callback is run in order of priority, and given
        * the opportunity to modify a value by returning a new value.
        *
        * The following example shows how a callback function is bound to a filter hook.
        * Note that $example is passed to the callback, (maybe) modified, then returned:
        *
        * <code>
        * function example_callback( $example ) {
        * 	// Maybe modify $example in some way
        * 	return $example;
        * }
        * add_filter( 'example_filter', 'example_callback' );
        * </code>
        *
        * Since WordPress 1.5.1, bound callbacks can take as many arguments as are
        * passed as parameters in the corresponding apply_filters() call. The $accepted_args
        * parameter allows for calling functions only when the number of args match.
        *
        * <strong>Note:</strong> the function will return true whether or not the callback
        * is valid. It is up to you to take care. This is done for optimization purposes,
        * so everything is as quick as possible.
        *
        * @global array $wp_filter      A multidimensional array of all hooks and the callbacks hooked to them.
        * @global array $merged_filters Tracks the tags that need to be merged for later. If the hook is added, it doesn't need to run through that process.
        *
        * @since 0.71
        *
        * @param string   $tag             The name of the filter to hook the $function_to_add callback to.
        * @param callback $function_to_add The callback to be run when the filter is applied.
        * @param int      $priority        (optional) The order in which the functions associated with a particular action are executed. Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
        *                                  Default 10.
        * @param int      $accepted_args   (optional) The number of arguments the function accepts.
        *                                  Default 1.
        * @return boolean true
        */
       function add_filter( $tag, $function_to_add, $priority = 10, $accepted_args = 1 ) {
       	global $wp_filter, $merged_filters;
   
       	$idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority);
       	$wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
       	unset( $merged_filters[ $tag ] );
       	return true;
       }
   
       /**
        * Check if any filter has been registered for a hook.
        *
        * @since 2.5.0
        *
        * @global array $wp_filter Stores all of the filters
        *
        * @param string $tag The name of the filter hook.
        * @param callback $function_to_check optional.
        * @return mixed If $function_to_check is omitted, returns boolean for whether the hook has anything registered.
        * 	When checking a specific function, the priority of that hook is returned, or false if the function is not attached.
        * 	When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false
        * 	(e.g.) 0, so use the === operator for testing the return value.
        */
       function has_filter($tag, $function_to_check = false) {
       	global $wp_filter;
   
       	$has = !empty($wp_filter[$tag]);
       	if ( false === $function_to_check || false == $has )
       		return $has;
   
       	if ( !$idx = _wp_filter_build_unique_id($tag, $function_to_check, false) )
       		return false;
   
       	foreach ( (array) array_keys($wp_filter[$tag]) as $priority ) {
       		if ( isset($wp_filter[$tag][$priority][$idx]) )
       			return $priority;
       	}
   
       	return false;
       }
   
       /**
        * Call the functions added to a filter hook.
        *
        * The callback functions attached to filter hook $tag are invoked by calling
        * this function. This function can be used to create a new filter hook by
        * simply calling this function with the name of the new hook specified using
        * the $tag parameter.
        *
        * The function allows for additional arguments to be added and passed to hooks.
        * <code>
        * // Our filter callback function
        * function example_callback( $string, $arg1, $arg2 ) {
        *	// (maybe) modify $string
        *	return $string;
        * }
        * add_filter( 'example_filter', 'example_callback', 10, 3 );
        *
        * // Apply the filters by calling the 'example_callback' function we
        * // "hooked" to 'example_filter' using the add_filter() function above.
        * // - 'example_filter' is the filter hook $tag
        * // - 'filter me' is the value being filtered
        * // - $arg1 and $arg2 are the additional arguments passed to the callback.
        * $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );
        * </code>
        *
        * @global array $wp_filter         Stores all of the filters
        * @global array $merged_filters    Merges the filter hooks using this function.
        * @global array $wp_current_filter stores the list of current filters with the current one last
        *
        * @since 0.71
        *
        * @param string $tag  The name of the filter hook.
        * @param mixed $value The value on which the filters hooked to <tt>$tag</tt> are applied on.
        * @param mixed $var   Additional variables passed to the functions hooked to <tt>$tag</tt>.
        * @return mixed The filtered value after all hooked functions are applied to it.
        */
       function apply_filters( $tag, $value ) {
       	global $wp_filter, $merged_filters, $wp_current_filter;
   
       	$args = array();
   
       	// Do 'all' actions first
       	if ( isset($wp_filter['all']) ) {
       		$wp_current_filter[] = $tag;
       		$args = func_get_args();
       		_wp_call_all_hook($args);
       	}
   
       	if ( !isset($wp_filter[$tag]) ) {
       		if ( isset($wp_filter['all']) )
       			array_pop($wp_current_filter);
       		return $value;
       	}
   
       	if ( !isset($wp_filter['all']) )
       		$wp_current_filter[] = $tag;
   
       	// Sort
       	if ( !isset( $merged_filters[ $tag ] ) ) {
       		ksort($wp_filter[$tag]);
       		$merged_filters[ $tag ] = true;
       	}
   
       	reset( $wp_filter[ $tag ] );
   
       	if ( empty($args) )
       		$args = func_get_args();
   
       	do {
       		foreach( (array) current($wp_filter[$tag]) as $the_ )
       			if ( !is_null($the_['function']) ){
       				$args[1] = $value;
       				$value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
       			}
   
       	} while ( next($wp_filter[$tag]) !== false );
   
       	array_pop( $wp_current_filter );
   
       	return $value;
       }
   
       /**
        * Execute functions hooked on a specific filter hook, specifying arguments in an array.
        *
        * @see apply_filters() This function is identical, but the arguments passed to the
        * functions hooked to <tt>$tag</tt> are supplied using an array.
        *
        * @since 3.0.0
        * @global array $wp_filter Stores all of the filters
        * @global array $merged_filters Merges the filter hooks using this function.
        * @global array $wp_current_filter stores the list of current filters with the current one last
        *
        * @param string $tag The name of the filter hook.
        * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
        * @return mixed The filtered value after all hooked functions are applied to it.
        */
       function apply_filters_ref_array($tag, $args) {
       	global $wp_filter, $merged_filters, $wp_current_filter;
   
       	// Do 'all' actions first
       	if ( isset($wp_filter['all']) ) {
       		$wp_current_filter[] = $tag;
       		$all_args = func_get_args();
       		_wp_call_all_hook($all_args);
       	}
   
       	if ( !isset($wp_filter[$tag]) ) {
       		if ( isset($wp_filter['all']) )
       			array_pop($wp_current_filter);
       		return $args[0];
       	}
   
       	if ( !isset($wp_filter['all']) )
       		$wp_current_filter[] = $tag;
   
       	// Sort
       	if ( !isset( $merged_filters[ $tag ] ) ) {
       		ksort($wp_filter[$tag]);
       		$merged_filters[ $tag ] = true;
       	}
   
       	reset( $wp_filter[ $tag ] );
   
       	do {
       		foreach( (array) current($wp_filter[$tag]) as $the_ )
       			if ( !is_null($the_['function']) )
       				$args[0] = call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
   
       	} while ( next($wp_filter[$tag]) !== false );
   
       	array_pop( $wp_current_filter );
   
       	return $args[0];
       }
   
       /**
        * Removes a function from a specified filter hook.
        *
        * This function removes a function attached to a specified filter hook. This
        * method can be used to remove default functions attached to a specific filter
        * hook and possibly replace them with a substitute.
        *
        * To remove a hook, the $function_to_remove and $priority arguments must match
        * when the hook was added. This goes for both filters and actions. No warning
        * will be given on removal failure.
        *
        * @since 1.2.0
        *
        * @param string $tag The filter hook to which the function to be removed is hooked.
        * @param callback $function_to_remove The name of the function which should be removed.
        * @param int $priority optional. The priority of the function (default: 10).
        * @param int $accepted_args optional. The number of arguments the function accepts (default: 1).
        * @return boolean Whether the function existed before it was removed.
        */
       function remove_filter( $tag, $function_to_remove, $priority = 10 ) {
       	$function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority);
   
       	$r = isset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
   
       	if ( true === $r) {
       		unset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
       		if ( empty($GLOBALS['wp_filter'][$tag][$priority]) )
       			unset($GLOBALS['wp_filter'][$tag][$priority]);
       		unset($GLOBALS['merged_filters'][$tag]);
       	}
   
       	return $r;
       }
   
       /**
        * Remove all of the hooks from a filter.
        *
        * @since 2.7.0
        *
        * @param string $tag The filter to remove hooks from.
        * @param int $priority The priority number to remove.
        * @return bool True when finished.
        */
       function remove_all_filters($tag, $priority = false) {
       	global $wp_filter, $merged_filters;
   
       	if( isset($wp_filter[$tag]) ) {
       		if( false !== $priority && isset($wp_filter[$tag][$priority]) )
       			unset($wp_filter[$tag][$priority]);
       		else
       			unset($wp_filter[$tag]);
       	}
   
       	if( isset($merged_filters[$tag]) )
       		unset($merged_filters[$tag]);
   
       	return true;
       }
   
       /**
        * Retrieve the name of the current filter or action.
        *
        * @since 2.5.0
        *
        * @return string Hook name of the current filter or action.
        */
       function current_filter() {
       	global $wp_current_filter;
       	return end( $wp_current_filter );
       }
   
       /**
        * Retrieve the name of the current action.
        *
        * @since 3.9.0
        *
        * @uses current_filter()
        *
        * @return string Hook name of the current action.
        */
       function current_action() {
       	return current_filter();
       }
   
       /**
        * Retrieve the name of a filter currently being processed.
        *
        * The function current_filter() only returns the most recent filter or action
        * being executed. did_action() returns true once the action is initially
        * processed. This function allows detection for any filter currently being
        * executed (despite not being the most recent filter to fire, in the case of
        * hooks called from hook callbacks) to be verified.
        *
        * @since 3.9.0
        *
        * @see current_filter()
        * @see did_action()
        * @global array $wp_current_filter Current filter.
        *
        * @param null|string $filter Optional. Filter to check. Defaults to null, which
        *                            checks if any filter is currently being run.
        * @return bool Whether the filter is currently in the stack
        */
       function doing_filter( $filter = null ) {
       	global $wp_current_filter;
   
       	if ( null === $filter ) {
       		return ! empty( $wp_current_filter );
       	}
   
       	return in_array( $filter, $wp_current_filter );
       }
   
       /**
        * Retrieve the name of an action currently being processed.
        *
        * @since 3.9.0
        *
        * @uses doing_filter()
        *
        * @param string|null $action Optional. Action to check. Defaults to null, which checks
        *                            if any action is currently being run.
        * @return bool Whether the action is currently in the stack.
        */
       function doing_action( $action = null ) {
       	return doing_filter( $action );
       }
   
       /**
        * Hooks a function on to a specific action.
        *
        * Actions are the hooks that the WordPress core launches at specific points
        * during execution, or when specific events occur. Plugins can specify that
        * one or more of its PHP functions are executed at these points, using the
        * Action API.
        *
        * @uses add_filter() Adds an action. Parameter list and functionality are the same.
        *
        * @since 1.2.0
        *
        * @param string $tag The name of the action to which the $function_to_add is hooked.
        * @param callback $function_to_add The name of the function you wish to be called.
        * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
        * @param int $accepted_args optional. The number of arguments the function accept (default 1).
        */
       function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
       	return add_filter($tag, $function_to_add, $priority, $accepted_args);
       }
   
       /**
        * Execute functions hooked on a specific action hook.
        *
        * This function invokes all functions attached to action hook $tag. It is
        * possible to create new action hooks by simply calling this function,
        * specifying the name of the new hook using the <tt>$tag</tt> parameter.
        *
        * You can pass extra arguments to the hooks, much like you can with
        * apply_filters().
        *
        * @see apply_filters() This function works similar with the exception that
        * nothing is returned and only the functions or methods are called.
        *
        * @since 1.2.0
        *
        * @global array $wp_filter Stores all of the filters
        * @global array $wp_actions Increments the amount of times action was triggered.
        *
        * @param string $tag The name of the action to be executed.
        * @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
        * @return null Will return null if $tag does not exist in $wp_filter array
        */
       function do_action($tag, $arg = '') {
       	global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
   
       	if ( ! isset($wp_actions[$tag]) )
       		$wp_actions[$tag] = 1;
       	else
       		++$wp_actions[$tag];
   
       	// Do 'all' actions first
       	if ( isset($wp_filter['all']) ) {
       		$wp_current_filter[] = $tag;
       		$all_args = func_get_args();
       		_wp_call_all_hook($all_args);
       	}
   
       	if ( !isset($wp_filter[$tag]) ) {
       		if ( isset($wp_filter['all']) )
       			array_pop($wp_current_filter);
       		return;
       	}
   
       	if ( !isset($wp_filter['all']) )
       		$wp_current_filter[] = $tag;
   
       	$args = array();
       	if ( is_array($arg) && 1 == count($arg) && isset($arg[0]) && is_object($arg[0]) ) // array(&$this)
       		$args[] =& $arg[0];
       	else
       		$args[] = $arg;
       	for ( $a = 2; $a < func_num_args(); $a++ )
       		$args[] = func_get_arg($a);
   
       	// Sort
       	if ( !isset( $merged_filters[ $tag ] ) ) {
       		ksort($wp_filter[$tag]);
       		$merged_filters[ $tag ] = true;
       	}
   
       	reset( $wp_filter[ $tag ] );
   
       	do {
       		foreach ( (array) current($wp_filter[$tag]) as $the_ )
       			if ( !is_null($the_['function']) )
       				call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
   
       	} while ( next($wp_filter[$tag]) !== false );
   
       	array_pop($wp_current_filter);
       }
   
       /**
        * Retrieve the number of times an action is fired.
        *
        * @since 2.1.0
        *
        * @global array $wp_actions Increments the amount of times action was triggered.
        *
        * @param string $tag The name of the action hook.
        * @return int The number of times action hook <tt>$tag</tt> is fired
        */
       function did_action($tag) {
       	global $wp_actions;
   
       	if ( ! isset( $wp_actions[ $tag ] ) )
       		return 0;
   
       	return $wp_actions[$tag];
       }
   
       /**
        * Execute functions hooked on a specific action hook, specifying arguments in an array.
        *
        * @see do_action() This function is identical, but the arguments passed to the
        * functions hooked to <tt>$tag</tt> are supplied using an array.
        *
        * @since 2.1.0
        *
        * @global array $wp_filter Stores all of the filters
        * @global array $wp_actions Increments the amount of times action was triggered.
        *
        * @param string $tag The name of the action to be executed.
        * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
        * @return null Will return null if $tag does not exist in $wp_filter array
        */
       function do_action_ref_array($tag, $args) {
       	global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
   
       	if ( ! isset($wp_actions[$tag]) )
       		$wp_actions[$tag] = 1;
       	else
       		++$wp_actions[$tag];
   
       	// Do 'all' actions first
       	if ( isset($wp_filter['all']) ) {
       		$wp_current_filter[] = $tag;
       		$all_args = func_get_args();
       		_wp_call_all_hook($all_args);
       	}
   
       	if ( !isset($wp_filter[$tag]) ) {
       		if ( isset($wp_filter['all']) )
       			array_pop($wp_current_filter);
       		return;
       	}
   
       	if ( !isset($wp_filter['all']) )
       		$wp_current_filter[] = $tag;
   
       	// Sort
       	if ( !isset( $merged_filters[ $tag ] ) ) {
       		ksort($wp_filter[$tag]);
       		$merged_filters[ $tag ] = true;
       	}
   
       	reset( $wp_filter[ $tag ] );
   
       	do {
       		foreach( (array) current($wp_filter[$tag]) as $the_ )
       			if ( !is_null($the_['function']) )
       				call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
   
       	} while ( next($wp_filter[$tag]) !== false );
   
       	array_pop($wp_current_filter);
       }
   
       /**
        * Check if any action has been registered for a hook.
        *
        * @since 2.5.0
        *
        * @see has_filter() has_action() is an alias of has_filter().
        *
        * @param string $tag The name of the action hook.
        * @param callback $function_to_check optional.
        * @return mixed If $function_to_check is omitted, returns boolean for whether the hook has anything registered.
        * 	When checking a specific function, the priority of that hook is returned, or false if the function is not attached.
        * 	When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false
        * 	(e.g.) 0, so use the === operator for testing the return value.
        */
       function has_action($tag, $function_to_check = false) {
       	return has_filter($tag, $function_to_check);
       }
   
       /**
        * Removes a function from a specified action hook.
        *
        * This function removes a function attached to a specified action hook. This
        * method can be used to remove default functions attached to a specific filter
        * hook and possibly replace them with a substitute.
        *
        * @since 1.2.0
        *
        * @param string $tag The action hook to which the function to be removed is hooked.
        * @param callback $function_to_remove The name of the function which should be removed.
        * @param int $priority optional The priority of the function (default: 10).
        * @return boolean Whether the function is removed.
        */
       function remove_action( $tag, $function_to_remove, $priority = 10 ) {
       	return remove_filter( $tag, $function_to_remove, $priority );
       }
   
       /**
        * Remove all of the hooks from an action.
        *
        * @since 2.7.0
        *
        * @param string $tag The action to remove hooks from.
        * @param int $priority The priority number to remove them from.
        * @return bool True when finished.
        */
       function remove_all_actions($tag, $priority = false) {
       	return remove_all_filters($tag, $priority);
       }
   
       //
       // Functions for handling plugins.
       //
   
       /**
        * Gets the basename of a plugin.
        *
        * This method extracts the name of a plugin from its filename.
        *
        * @since 1.5.0
        *
        * @access private
        *
        * @param string $file The filename of plugin.
        * @return string The name of a plugin.
        * @uses WP_PLUGIN_DIR
        */
       function plugin_basename( $file ) {
       	global $wp_plugin_paths;
   
       	foreach ( $wp_plugin_paths as $dir => $realdir ) {
       		if ( strpos( $file, $realdir ) === 0 ) {
       			$file = $dir . substr( $file, strlen( $realdir ) );
       		}
       	}
   
       	$file = wp_normalize_path( $file );
       	$plugin_dir = wp_normalize_path( WP_PLUGIN_DIR );
       	$mu_plugin_dir = wp_normalize_path( WPMU_PLUGIN_DIR );
   
       	$file = preg_replace('#^' . preg_quote($plugin_dir, '#') . '/|^' . preg_quote($mu_plugin_dir, '#') . '/#','',$file); // get relative path from plugins dir
       	$file = trim($file, '/');
       	return $file;
       }
   
       /**
        * Register a plugin's real path.
        *
        * This is used in plugin_basename() to resolve symlinked paths.
        *
        * @since 3.9.0
        *
        * @see plugin_basename()
        *
        * @param string $file Known path to the file.
        * @return bool Whether the path was able to be registered.
        */
       function wp_register_plugin_realpath( $file ) {
       	global $wp_plugin_paths;
   
       	// Normalize, but store as static to avoid recalculation of a constant value
       	static $wp_plugin_path, $wpmu_plugin_path;
       	if ( ! isset( $wp_plugin_path ) ) {
       		$wp_plugin_path   = wp_normalize_path( WP_PLUGIN_DIR   );
       		$wpmu_plugin_path = wp_normalize_path( WPMU_PLUGIN_DIR );
       	}
   
       	$plugin_path = wp_normalize_path( dirname( $file ) );
       	$plugin_realpath = wp_normalize_path( dirname( realpath( $file ) ) );
   
       	if ( $plugin_path === $wp_plugin_path || $plugin_path === $wpmu_plugin_path ) {
       		return false;
       	}
   
       	if ( $plugin_path !== $plugin_realpath ) {
       		$wp_plugin_paths[ $plugin_path ] = $plugin_realpath;
       	}
   
       	return true;
       }
   
       /**
        * Gets the filesystem directory path (with trailing slash) for the plugin __FILE__ passed in
        *
        * @since 2.8.0
        *
        * @param string $file The filename of the plugin (__FILE__)
        * @return string the filesystem path of the directory that contains the plugin
        */
       function plugin_dir_path( $file ) {
       	return trailingslashit( dirname( $file ) );
       }
   
       /**
        * Gets the URL directory path (with trailing slash) for the plugin __FILE__ passed in
        *
        * @since 2.8.0
        *
        * @param string $file The filename of the plugin (__FILE__)
        * @return string the URL path of the directory that contains the plugin
        */
       function plugin_dir_url( $file ) {
       	return trailingslashit( plugins_url( '', $file ) );
       }
   
       /**
        * Set the activation hook for a plugin.
        *
        * When a plugin is activated, the action 'activate_PLUGINNAME' hook is
        * called. In the name of this hook, PLUGINNAME is replaced with the name
        * of the plugin, including the optional subdirectory. For example, when the
        * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
        * the name of this hook will become 'activate_sampleplugin/sample.php'.
        *
        * When the plugin consists of only one file and is (as by default) located at
        * wp-content/plugins/sample.php the name of this hook will be
        * 'activate_sample.php'.
        *
        * @since 2.0.0
        *
        * @param string $file The filename of the plugin including the path.
        * @param callback $function the function hooked to the 'activate_PLUGIN' action.
        */
       function register_activation_hook($file, $function) {
       	$file = plugin_basename($file);
       	add_action('activate_' . $file, $function);
       }
   
       /**
        * Set the deactivation hook for a plugin.
        *
        * When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
        * called. In the name of this hook, PLUGINNAME is replaced with the name
        * of the plugin, including the optional subdirectory. For example, when the
        * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
        * the name of this hook will become 'deactivate_sampleplugin/sample.php'.
        *
        * When the plugin consists of only one file and is (as by default) located at
        * wp-content/plugins/sample.php the name of this hook will be
        * 'deactivate_sample.php'.
        *
        * @since 2.0.0
        *
        * @param string $file The filename of the plugin including the path.
        * @param callback $function the function hooked to the 'deactivate_PLUGIN' action.
        */
       function register_deactivation_hook($file, $function) {
       	$file = plugin_basename($file);
       	add_action('deactivate_' . $file, $function);
       }
   
       /**
        * Set the uninstallation hook for a plugin.
        *
        * Registers the uninstall hook that will be called when the user clicks on the
        * uninstall link that calls for the plugin to uninstall itself. The link won't
        * be active unless the plugin hooks into the action.
        *
        * The plugin should not run arbitrary code outside of functions, when
        * registering the uninstall hook. In order to run using the hook, the plugin
        * will have to be included, which means that any code laying outside of a
        * function will be run during the uninstall process. The plugin should not
        * hinder the uninstall process.
        *
        * If the plugin can not be written without running code within the plugin, then
        * the plugin should create a file named 'uninstall.php' in the base plugin
        * folder. This file will be called, if it exists, during the uninstall process
        * bypassing the uninstall hook. The plugin, when using the 'uninstall.php'
        * should always check for the 'WP_UNINSTALL_PLUGIN' constant, before
        * executing.
        *
        * @since 2.7.0
        *
        * @param string $file
        * @param callback $callback The callback to run when the hook is called. Must be a static method or function.
        */
       function register_uninstall_hook( $file, $callback ) {
       	if ( is_array( $callback ) && is_object( $callback[0] ) ) {
       		_doing_it_wrong( __FUNCTION__, __( 'Only a static class method or function can be used in an uninstall hook.' ), '3.1' );
       		return;
       	}
   
       	// The option should not be autoloaded, because it is not needed in most
       	// cases. Emphasis should be put on using the 'uninstall.php' way of
       	// uninstalling the plugin.
       	$uninstallable_plugins = (array) get_option('uninstall_plugins');
       	$uninstallable_plugins[plugin_basename($file)] = $callback;
       	update_option('uninstall_plugins', $uninstallable_plugins);
       }
   
       /**
        * Calls the 'all' hook, which will process the functions hooked into it.
        *
        * The 'all' hook passes all of the arguments or parameters that were used for
        * the hook, which this function was called for.
        *
        * This function is used internally for apply_filters(), do_action(), and
        * do_action_ref_array() and is not meant to be used from outside those
        * functions. This function does not check for the existence of the all hook, so
        * it will fail unless the all hook exists prior to this function call.
        *
        * @since 2.5.0
        * @access private
        *
        * @uses $wp_filter Used to process all of the functions in the 'all' hook
        *
        * @param array $args The collected parameters from the hook that was called.
        */
       function _wp_call_all_hook($args) {
       	global $wp_filter;
   
       	reset( $wp_filter['all'] );
       	do {
       		foreach( (array) current($wp_filter['all']) as $the_ )
       			if ( !is_null($the_['function']) )
       				call_user_func_array($the_['function'], $args);
   
       	} while ( next($wp_filter['all']) !== false );
       }
   
       /**
        * Build Unique ID for storage and retrieval.
        *
        * The old way to serialize the callback caused issues and this function is the
        * solution. It works by checking for objects and creating an a new property in
        * the class to keep track of the object and new objects of the same class that
        * need to be added.
        *
        * It also allows for the removal of actions and filters for objects after they
        * change class properties. It is possible to include the property $wp_filter_id
        * in your class and set it to "null" or a number to bypass the workaround.
        * However this will prevent you from adding new classes and any new classes
        * will overwrite the previous hook by the same class.
        *
        * Functions and static method callbacks are just returned as strings and
        * shouldn't have any speed penalty.
        *
        * @access private
        * @since 2.2.3
        * @link http://trac.wordpress.org/ticket/3875
        *
        * @global array $wp_filter Storage for all of the filters and actions
        * @param string $tag Used in counting how many hooks were applied
        * @param callback $function Used for creating unique id
        * @param int|bool $priority Used in counting how many hooks were applied. If === false and $function is an object reference, we return the unique id only if it already has one, false otherwise.
        * @return string|bool Unique ID for usage as array key or false if $priority === false and $function is an object reference, and it does not already have a unique id.
        */
       function _wp_filter_build_unique_id($tag, $function, $priority) {
       	global $wp_filter;
       	static $filter_id_count = 0;
   
       	if ( is_string($function) )
       		return $function;
   
       	if ( is_object($function) ) {
       		// Closures are currently implemented as objects
       		$function = array( $function, '' );
       	} else {
       		$function = (array) $function;
       	}
   
       	if (is_object($function[0]) ) {
       		// Object Class Calling
       		if ( function_exists('spl_object_hash') ) {
       			return spl_object_hash($function[0]) . $function[1];
       		} else {
       			$obj_idx = get_class($function[0]).$function[1];
       			if ( !isset($function[0]->wp_filter_id) ) {
       				if ( false === $priority )
       					return false;
       				$obj_idx .= isset($wp_filter[$tag][$priority]) ? count((array)$wp_filter[$tag][$priority]) : $filter_id_count;
       				$function[0]->wp_filter_id = $filter_id_count;
       				++$filter_id_count;
       			} else {
       				$obj_idx .= $function[0]->wp_filter_id;
       			}
   
       			return $obj_idx;
       		}
       	} else if ( is_string($function[0]) ) {
       		// Static Calling
       		return $function[0] . '::' . $function[1];
       	}
       }
       ```
   
 * _[ No bumping please_

The topic ‘Warning: call_user_func_array() expects parameter 1’ is closed to new
replies.

 * 0 replies
 * 1 participant
 * Last reply from: [sickwit](https://wordpress.org/support/users/sickwit/)
 * Last activity: [12 years, 3 months ago](https://wordpress.org/support/topic/warning-call_user_func_array-expects-parameter-1-2/)
 * Status: not resolved

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