Hi @stephw
Because the ‘member_lastname’ is saved AFTER the ‘member_firstname’ (order of fields), you can simply hook into just the lastname filter and run your code there like so:
<?php
function my_acf_update_value( $value, $post_id, $field ) {
// vars
$new_title = get_field('member_firstname', $post_id) . ' ' . $value;
$new_slug = santize_title( $new_title );
// update post
// http://codex.wordpress.org/Function_Reference/wp_update_post
}
add_filter('acf/update_value/name=member_lastname', 'my_acf_update_value', 10, 3);
?>
I’ll leave the updata_post bit to you.
Cheers
E
