Defined (1)

The function is defined in the following location(s).

/wp-includes/nav-menu-template.php  

function wp_nav_menu( $args = array() ) { 
    static $menu_id_slugs = array(); 
 
    $defaults = array( 'menu' => '', 'container' => 'div', 'container_class' => '', 'container_id' => '', 'menu_class' => 'menu', 'menu_id' => '',  
    'echo' => true, 'fallback_cb' => 'wp_page_menu', 'before' => '', 'after' => '', 'link_before' => '', 'link_after' => '', 'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>', 'item_spacing' => 'preserve',  
    'depth' => 0, walker => '', 'theme_location' => '' ); 
 
    $args = wp_parse_args( $args, $defaults ); 
 
    if ( ! in_array( $args['item_spacing'], array( 'preserve', 'discard' ), true ) ) { 
        // invalid value, fall back to default. 
        $args['item_spacing'] = $defaults['item_spacing']; 
    } 
 
    /** 
     * Filters the arguments used to display a navigation menu. 
     * 
     * @since 3.0.0 
     * 
     * @see wp_nav_menu() 
     * 
     * @param array $args Array of wp_nav_menu() arguments. 
     */ 
    $args = apply_filters( 'wp_nav_menu_args', $args ); 
    $args = (object) $args; 
 
    /** 
     * Filters whether to short-circuit the wp_nav_menu() output. 
     * 
     * Returning a non-null value to the filter will short-circuit 
     * wp_nav_menu(), echoing that value if $args->echo is true,  
     * returning that value otherwise. 
     * 
     * @since 3.9.0 
     * 
     * @see wp_nav_menu() 
     * 
     * @param string|null $output Nav menu output to short-circuit with. Default null. 
     * @param stdClass    $args   An object containing wp_nav_menu() arguments. 
     */ 
    $nav_menu = apply_filters( 'pre_wp_nav_menu', null, $args ); 
 
    if ( null !== $nav_menu ) { 
        if ( $args->echo ) { 
            echo $nav_menu; 
            return; 
        } 
 
        return $nav_menu; 
    } 
 
    // Get the nav menu based on the requested menu 
    $menu = wp_get_nav_menu_object( $args->menu ); 
 
    // Get the nav menu based on the theme_location 
    if ( ! $menu && $args->theme_location && ( $locations = get_nav_menu_locations() ) && isset( $locations[ $args->theme_location ] ) ) 
        $menu = wp_get_nav_menu_object( $locations[ $args->theme_location ] ); 
 
    // get the first menu that has items if we still can't find a menu 
    if ( ! $menu && !$args->theme_location ) { 
        $menus = wp_get_nav_menus(); 
        foreach ( $menus as $menu_maybe ) { 
            if ( $menu_items = wp_get_nav_menu_items( $menu_maybe->term_id, array( 'update_post_term_cache' => false ) ) ) { 
                $menu = $menu_maybe; 
                break; 
            } 
        } 
    } 
 
    if ( empty( $args->menu ) ) { 
        $args->menu = $menu; 
    } 
 
    // If the menu exists, get its items. 
    if ( $menu && ! is_wp_error($menu) && !isset($menu_items) ) 
        $menu_items = wp_get_nav_menu_items( $menu->term_id, array( 'update_post_term_cache' => false ) ); 
 
    /** 
     * If no menu was found: 
     *  - Fall back (if one was specified), or bail. 
     * 
     * If no menu items were found: 
     *  - Fall back, but only if no theme location was specified. 
     *  - Otherwise, bail. 
     */ 
    if ( ( !$menu || is_wp_error($menu) || ( isset($menu_items) && empty($menu_items) && !$args->theme_location ) ) 
        && isset( $args->fallback_cb ) && $args->fallback_cb && is_callable( $args->fallback_cb ) ) 
            return call_user_func( $args->fallback_cb, (array) $args ); 
 
    if ( ! $menu || is_wp_error( $menu ) ) 
        return false; 
 
    $nav_menu = $items = ''; 
 
    $show_container = false; 
    if ( $args->container ) { 
        /** 
         * Filters the list of HTML tags that are valid for use as menu containers. 
         * 
         * @since 3.0.0 
         * 
         * @param array $tags The acceptable HTML tags for use as menu containers. 
         *                    Default is array containing 'div' and 'nav'. 
         */ 
        $allowed_tags = apply_filters( 'wp_nav_menu_container_allowedtags', array( 'div', 'nav' ) ); 
        if ( is_string( $args->container ) && in_array( $args->container, $allowed_tags ) ) { 
            $show_container = true; 
            $class = $args->container_class ? ' class="' . esc_attr( $args->container_class ) . '"' : ' class="menu-'. $menu->slug .'-container"'; 
            $id = $args->container_id ? ' id="' . esc_attr( $args->container_id ) . '"' : ''; 
            $nav_menu .= '<'. $args->container . $id . $class . '>'; 
        } 
    } 
 
    // Set up the $menu_item variables 
    _wp_menu_item_classes_by_context( $menu_items ); 
 
    $sorted_menu_items = $menu_items_with_children = array(); 
    foreach ( (array) $menu_items as $menu_item ) { 
        $sorted_menu_items[ $menu_item->menu_order ] = $menu_item; 
        if ( $menu_item->menu_item_parent ) 
            $menu_items_with_children[ $menu_item->menu_item_parent ] = true; 
    } 
 
    // Add the menu-item-has-children class where applicable 
    if ( $menu_items_with_children ) { 
        foreach ( $sorted_menu_items as &$menu_item ) { 
            if ( isset( $menu_items_with_children[ $menu_item->ID ] ) ) 
                $menu_item->classes[] = 'menu-item-has-children'; 
        } 
    } 
 
    unset( $menu_items, $menu_item ); 
 
    /** 
     * Filters the sorted list of menu item objects before generating the menu's HTML. 
     * 
     * @since 3.1.0 
     * 
     * @param array    $sorted_menu_items The menu items, sorted by each menu item's menu order. 
     * @param stdClass $args              An object containing wp_nav_menu() arguments. 
     */ 
    $sorted_menu_items = apply_filters( 'wp_nav_menu_objects', $sorted_menu_items, $args ); 
 
    $items .= walk_nav_menu_tree( $sorted_menu_items, $args->depth, $args ); 
    unset($sorted_menu_items); 
 
    // Attributes 
    if ( ! empty( $args->menu_id ) ) { 
        $wrap_id = $args->menu_id; 
    } else { 
        $wrap_id = 'menu-' . $menu->slug; 
        while ( in_array( $wrap_id, $menu_id_slugs ) ) { 
            if ( preg_match( '#-(\d+)$#', $wrap_id, $matches ) ) 
                $wrap_id = preg_replace('#-(\d+)$#', '-' . ++$matches[1], $wrap_id ); 
            else 
                $wrap_id = $wrap_id . '-1'; 
        } 
    } 
    $menu_id_slugs[] = $wrap_id; 
 
    $wrap_class = $args->menu_class ? $args->menu_class : ''; 
 
    /** 
     * Filters the HTML list content for navigation menus. 
     * 
     * @since 3.0.0 
     * 
     * @see wp_nav_menu() 
     * 
     * @param string   $items The HTML list content for the menu items. 
     * @param stdClass $args  An object containing wp_nav_menu() arguments. 
     */ 
    $items = apply_filters( 'wp_nav_menu_items', $items, $args ); 
    /** 
     * Filters the HTML list content for a specific navigation menu. 
     * 
     * @since 3.0.0 
     * 
     * @see wp_nav_menu() 
     * 
     * @param string   $items The HTML list content for the menu items. 
     * @param stdClass $args  An object containing wp_nav_menu() arguments. 
     */ 
    $items = apply_filters( "wp_nav_menu_{$menu->slug}_items", $items, $args ); 
 
    // Don't print any markup if there are no items at this point. 
    if ( empty( $items ) ) 
        return false; 
 
    $nav_menu .= sprintf( $args->items_wrap, esc_attr( $wrap_id ), esc_attr( $wrap_class ), $items ); 
    unset( $items ); 
 
    if ( $show_container ) 
        $nav_menu .= '</' . $args->container . '>'; 
 
    /** 
     * Filters the HTML content for navigation menus. 
     * 
     * @since 3.0.0 
     * 
     * @see wp_nav_menu() 
     * 
     * @param string   $nav_menu The HTML content for the navigation menu. 
     * @param stdClass $args     An object containing wp_nav_menu() arguments. 
     */ 
    $nav_menu = apply_filters( 'wp_nav_menu', $nav_menu, $args ); 
 
    if ( $args->echo ) 
        echo $nav_menu; 
    else 
        return $nav_menu; 
}