trackback_url_list( string $tb_list, int $post_id )
- Since
- 1.0.0
- Source
wp-includes/post.php:6169
Compatibility
- WordPress
- since 1.0.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$tb_liststring- Comma separated list of URLs.
$post_idint- Post ID.
Performance profile
How much work a call to trackback_url_list() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Expensive
- Scaling
- Scales with input
- Instructions
- 5–37
- Plugin surface
- None
- Called by
- 0
Reaches an outbound HTTP request via wp_safe_remote_post().
The body loops, so the work grows with what you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 53.
Nothing here hands control to plugin code.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- querycontent query
get_post()called directly - optionoption read or write
get_option()one call below trackback_url_list() - httpoutbound HTTP request
wp_safe_remote_post()one call below trackback_url_list()
Further down the call graph this can also reach hook, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost trackback_url_list() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
empty($tb_list) | 5 | none |
!empty($tb_list) | 10 | get_post() |
!empty($tb_list) | 31–37 | get_post(), ->to_array(), strip_tags(), explode() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 53 | 5–37 | 6 | |
| 8.5 | 53 | 5–37 | 6 | |
| 8.4 | 53 | 5–37 | 6 | 5 fewer instructions than PHP 8.3 |
| 8.3 | 58 | 5–40 | 6 | |
| 8.2 | 58 | 5–40 | 6 | |
| 8.1 | 58 | 5–40 | 6 | 2 fewer instructions than PHP 7.4 |
| 7.4 | 60 | 5–41 | 6 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 3
- get_post()Retrieves post data given a post ID or post object.
- trackback()Sends a Trackback.
- wp_unslash()Removes slashes from a string or recursively removes slashes from strings within an array.
Source code
function trackback_url_list( $tb_list, $post_id ) { if ( ! empty( $tb_list ) ) { // Get post data. $post = get_post( $post_id ); if ( ! $post ) { return; } $postdata = $post->to_array(); // Form an excerpt. $excerpt = strip_tags( $postdata['post_excerpt'] ? $postdata['post_excerpt'] : $postdata['post_content'] ); if ( strlen( $excerpt ) > 255 ) { $excerpt = substr( $excerpt, 0, 252 ) . '…'; } $trackback_urls = explode( ',', $tb_list ); foreach ( (array) $trackback_urls as $tb_url ) { $tb_url = trim( $tb_url ); trackback( $tb_url, wp_unslash( $postdata['post_title'] ), $excerpt, $post_id ); } }}Changelog
Introduced in 1.0.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/post.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.