添加include到wordpress functions.php返回

I have two scripts I need to combine for wordpress, basically my own custom share this links

The function which puts it in the_content();

add_filter( "the_content",'addstyling', 5 );

function addstyling($content){  
    global $post;
    return ''.$content.'<br><br>Sharethis';
}

and the other code is just html inside a file, used through an include:

include(TEMPLATEPATH . '/includes/share.php'); 

any help would be great, Im a newbie to PHP

Not quite sure what you're asking, but if you want your include file adding to the post:

function addstyling($content){  
    global $post;
    $share = file_get_contents(TEMPLATEPATH . '/includes/share.php'); 
    return $share . $content . '<br><br>Sharethis';
}