Wordpress - Paginação interna de Posts/Pages

/* Paginação interna de posts ou pages */

// No functions.php

if (!function_exists('custom_wp_link_pages')) :

    function custom_wp_link_pages($args = '') {
        $defaults = array(
            'before' => '<p class="post-pagination"><span class="post-pages">' . __('Páginas:') . '</span>',
            'after' => '</p>',
            'text_before' => '',
            'text_after' => '',
            'next_or_number' => 'number',
            'nextpagelink' => __('Next page'),
            'previouspagelink' => __('Previous page'),
            'pagelink' => '%',
            'echo' => 1
        );
        $r = wp_parse_args($args, $defaults);
        $r = apply_filters('wp_link_pages_args', $r);
        extract($r, EXTR_SKIP);
        global $page, $numpages, $multipage, $more, $pagenow;
        $output = '';
        if ($multipage) {
            if ('number' == $next_or_number) {
                $output .= $before;
                for ($i = 1; $i < ( $numpages + 1 ); $i = $i + 1) {
                    $j = str_replace('%', $i, $pagelink);
                    $output .= ' ';
                    if ($i != $page || ( (!$more ) && ( $page == 1 ) ))
                        $output .= _wp_link_page($i);
                    else
                        $output .= '<span class="current-post-page">';

                    $output .= $text_before . $j . $text_after;
                    if ($i != $page || ( (!$more ) && ( $page == 1 ) ))
                        $output .= '</a>';
                    else
                        $output .= '</span>';
                }
                $output .= $after;
            } else {
                if ($more) {
                    $output .= $before;
                    $i = $page - 1;
                    if ($i && $more) {
                        $output .= _wp_link_page($i);
                        $output .= $text_before . $previouspagelink . $text_after . '</a>';
                    }
                    $i = $page + 1;
                    if ($i <= $numpages && $more) {
                        $output .= _wp_link_page($i);
                        $output .= $text_before . $nextpagelink . $text_after . '</a>';
                    }
                    $output .= $after;
                }
            }
        }
        if ($echo)
            echo $output;
        return $output;
    }

endif;


// No single.php ou template após o the_content();

custom_wp_link_pages();