trackback( string $trackback_url, string $title, string $excerpt, int $post_id ): int|false|void

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$trackback_urlstring

URL to send trackbacks.

$titlestring

Title of post.

$excerptstring

Excerpt of post.

$post_idint

Post ID.

Return value

int|false|void

Database query from update.

Performance profile

How much work a call to trackback() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Expensive

Reaches an outbound HTTP request via wp_safe_remote_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

8–54

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 56.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

2

2 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• optionoption read or writeget_option()called directly
• httpoutbound HTTP requestwp_safe_remote_post()called directly
• sqldatabase query->query()called directly
• querycontent queryget_post()one call below trackback()
• hookthird-party callbacksapply_filters()one call below trackback()
• cacheobject cachewp_cache_get()one call below trackback()
• serializeserialisationmaybe_unserialize()one call below trackback()

Further down the call graph this can also reach transient. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 3 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost trackback() can have, taken from its control-flow graph on PHP 8.5.

Uses · 4

• get_permalink()Retrieves the full permalink for the current post or post ID.
• get_option()Retrieves an option value based on an option name.
• wp_safe_remote_post()Retrieves the raw response from a safe HTTP request using the POST method.
• is_wp_error()Checks whether the given variable is a WordPress Error.

Used by · 2

• do_trackbacks()Performs trackbacks.
• trackback_url_list()Does trackbacks for a list of URLs.

Source code

View on Trac ↗View on GitHub ↗

3318function trackback( $trackback_url, $title, $excerpt, $post_id ) {3319	global $wpdb;3320 3321	if ( empty( $trackback_url ) ) {3322		return;3323	}3324 3325	$options            = array();3326	$options['timeout'] = 10;3327	$options['body']    = array(3328		'title'     => $title,3329		'url'       => get_permalink( $post_id ),3330		'blog_name' => get_option( 'blogname' ),3331		'excerpt'   => $excerpt,3332	);3333 3334	$response = wp_safe_remote_post( $trackback_url, $options );3335 3336	if ( is_wp_error( $response ) ) {3337		return;3338	}3339 3340	$wpdb->query( $wpdb->prepare( "UPDATE $wpdb->posts SET pinged = CONCAT(pinged, '\n', %s) WHERE ID = %d", $trackback_url, $post_id ) );3341	return $wpdb->query( $wpdb->prepare( "UPDATE $wpdb->posts SET to_ping = TRIM(REPLACE(to_ping, %s, '')) WHERE ID = %d", $trackback_url, $post_id ) );3342}

Changelog

Introduced in 0.71. One change between 6.7.7 and 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.0.4 tag, from src/wp-includes/comment.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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