get_day_link( bool|int $year, bool|int $month, bool|int $day )

function get_day_link($year, $month, $day) {
	global $wp_rewrite;
	if ( !$year )
		$year = gmdate('Y', current_time('timestamp'));
	if ( !$month )
		$month = gmdate('m', current_time('timestamp'));
	if ( !$day )
		$day = gmdate('j', current_time('timestamp'));

	$daylink = $wp_rewrite->get_day_permastruct();
	if ( !empty($daylink) ) {
		$daylink = str_replace('%year%', $year, $daylink);
		$daylink = str_replace('%monthnum%', zeroise(intval($month), 2), $daylink);
		$daylink = str_replace('%day%', zeroise(intval($day), 2), $daylink);
		$daylink = home_url( user_trailingslashit( $daylink, 'day' ) );
	} else {
		$daylink = home_url( '?m=' . $year . zeroise( $month, 2 ) . zeroise( $day, 2 ) );
	}

	/**
	 * Filters the day archive permalink.
	 *
	 * @since WP-1.5.0
	 *
	 * @param string $daylink Permalink for the day archive.
	 * @param int    $year    Year for the archive.
	 * @param int    $month   Month for the archive.
	 * @param int    $day     The day for the archive.
	 */
	return apply_filters( 'day_link', $daylink, $year, $month, $day );
}