trackback( string $trackback_url, string $title, string $excerpt, int $ID )

发送一个Trackback。
Send a Trackback.

目录锚点：#说明#参数#源码

说明（Description）

发送trackback时更新数据库以防止重复。

参数（Parameters）

源码（Source）

/**
 * Send a Trackback.
 *
 * Updates database when sending trackback to prevent duplicates.
 *
 * @since 0.71
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $trackback_url URL to send trackbacks.
 * @param string $title Title of post.
 * @param string $excerpt Excerpt of post.
 * @param int $ID Post ID.
 * @return int|false|void Database query from update.
 */
function trackback($trackback_url, $title, $excerpt, $ID) {
	global $wpdb;

	if ( empty($trackback_url) )
		return;

	$options = array();
	$options['timeout'] = 4;
	$options['body'] = array(
		'title' => $title,
		'url' => get_permalink($ID),
		'blog_name' => get_option('blogname'),
		'excerpt' => $excerpt
	);

	$response = wp_safe_remote_post( $trackback_url, $options );

	if ( is_wp_error( $response ) )
		return;

	$wpdb->query( $wpdb->prepare("UPDATE $wpdb->posts SET pinged = CONCAT(pinged, '
', %s) WHERE ID = %d", $trackback_url, $ID) );
	return $wpdb->query( $wpdb->prepare("UPDATE $wpdb->posts SET to_ping = TRIM(REPLACE(to_ping, %s, '')) WHERE ID = %d", $trackback_url, $ID) );
}