Add a pingback url auto-discovery header for singularly identifiable articles.
<?php
if ( ! function_exists( 'prefix_pingback_header' ) ) {
/**
* Add a pingback url auto-discovery header for singularly identifiable articles.
*/
function prefix_pingback_header() {
if ( is_singular() && pings_open() ) {
printf( '<link rel="pingback" href="%s">' . "\n", get_bloginfo( 'pingback_url' ) );
}
}
add_action( 'wp_head', 'prefix_pingback_header' );
}