wp_get_attachment_caption( int $post_id = 0 ): string|false
- Since
- 4.6.0
- Source
wp-includes/post.php:7265
Compatibility
- WordPress
- since 4.6.0
- 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
$post_idintoptional- Attachment ID. Default is the ID of the global
$post.Default:0
Return value
string|false- Attachment caption on success, false on failure.
Performance profile
How much work a call to wp_get_attachment_caption() 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
- Heavy
- Scaling
- Constant
- Instructions
- 9–20
- Plugin surface
- 1 hook
- Called by
- 2
Reaches the database via get_post().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 22.
Third-party callbacks on 'wp_get_attachment_caption' run inside this call, and their cost is not bounded by anything here.
2 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- querycontent query
get_post()called directly - hookthird-party callbacks
apply_filters()called directly
Further down the call graph this can also reach option, 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 · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_get_attachment_caption() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 9–12 | get_post() |
| always | 20 | get_post(), apply_filters() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 22 instructions, 9–20 executed per call, 2 branches. The work does not change between versions.
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.
Hooks and filters fired · 1
One hook fires while wp_get_attachment_caption() runs, in this order:
- apply_filters( wp_get_attachment_caption )filterline 7287 (+22 into the body)
Filters the attachment caption.
Uses · 2
- get_post()Retrieves post data given a post ID or post object.
- apply_filters()Calls the callback functions that have been added to a filter hook.
Used by · 2
- get_the_post_thumbnail_caption()Returns the post thumbnail caption.
- twenty_twenty_one_post_thumbnail()Displays an optional post thumbnail.
Source code
function wp_get_attachment_caption( $post_id = 0 ) { $post_id = (int) $post_id; $post = get_post( $post_id ); if ( ! $post ) { return false; } if ( 'attachment' !== $post->post_type ) { return false; } $caption = $post->post_excerpt; /** * Filters the attachment caption. * * @since 4.6.0 * * @param string $caption Caption for the given attachment. * @param int $post_id Attachment ID. */ return apply_filters( 'wp_get_attachment_caption', $caption, $post->ID );}Changelog
Introduced in 4.6.0. 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.