I have a function that can load any page content to another page simply like this:

add_shortcode( 'load_content', 'fc_load_content' );
function fc_load_content($params) {
    extract(shortcode_atts(array('id' => -1), $params));

    return apply_filters('the_content', get_post($id)->post_content);
}

In any page I can add block with [load_content id="123"] and it will load content of page id 123 to another page. Thats ok. But when I do [load_content id="123"] in page with ID 123 it will cause infinite loop till execution timeout. It’s user problem – wrong ID. But how to break this infinite loading loop in function fc_load_content? I wasn’t able to get ID of “calling” page so I can’t compare it to param ID. Thank you.