WP_Query::the_post()
- Since
- 1.5.0
- Source
wp-includes/class-wp-query.php:3768
Description
Retrieves the next post, sets up the post, sets the 'in the loop' property to true.
Compatibility
- WordPress
- since 1.5.0
- 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.
Performance profile
How much work a call to WP_Query::the_post() 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
- 5–8
- Plugin surface
- 1 hook
- Called by
- 0
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 91.
Third-party callbacks on 'loop_start' run inside this call, and their cost is not bounded by anything here.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- hookthird-party callbacks
do_action_ref_array()called directly - querycontent query
get_post()called directly
Further down the call graph this can also reach cache, option, 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 · 1 distinct outcome
One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Query::the_post() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 5–8 | none |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 91 | 5–8 | 8 | |
| 8.5 | 91 | 5–8 | 8 | |
| 8.4 | 91 | 5–8 | 8 | |
| 8.3 | 91 | 5–8 | 8 | |
| 8.2 | 91 | 5–8 | 8 | |
| 8.1 | 91 | 5–8 | 8 | 8 more instructions than PHP 7.4 |
| 7.4 | 83 | 21–74 | 7 |
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_Query::the_post() runs, in this order:
Uses · 6
- _prime_post_caches()Adds any posts from the given IDs to the cache that do not already exist in cache.
- update_post_author_caches()Updates post author user caches for a list of post objects.
- do_action_ref_array()Calls the callback functions that have been added to an action hook, specifying arguments in an array.
- get_post()Retrieves post data given a post ID or post object.
- WP_Query::next_post()Sets up the next post and iterate current post index.
- WP_Query::setup_postdata()Sets up global post data.
Source code
public function the_post() { global $post; if ( ! $this->in_the_loop ) { if ( 'all' === $this->query_vars['fields'] ) { // Full post objects queried. $post_objects = $this->posts; } else { if ( 'ids' === $this->query_vars['fields'] ) { // Post IDs queried. $post_ids = $this->posts; } else { // Only partial objects queried, need to prime the cache for the loop. $post_ids = array_reduce( $this->posts, function ( $carry, $post ) { if ( isset( $post->ID ) ) { $carry[] = $post->ID; } return $carry; }, array() ); } _prime_post_caches( $post_ids, $this->query_vars['update_post_term_cache'], $this->query_vars['update_post_meta_cache'] ); $post_objects = array_map( 'get_post', $post_ids ); } update_post_author_caches( $post_objects ); } $this->in_the_loop = true; $this->before_loop = false; if ( -1 === $this->current_post ) { // Loop has just started. /** * Fires once the loop is started. * * @since 2.0.0 * * @param WP_Query $query The WP_Query instance (passed by reference). */ do_action_ref_array( 'loop_start', array( &$this ) ); } $post = $this->next_post(); // Ensure a full post object is available. if ( 'all' !== $this->query_vars['fields'] ) { if ( 'ids' === $this->query_vars['fields'] ) { // Post IDs queried. $post = get_post( $post ); } elseif ( isset( $post->ID ) ) { /* * Partial object queried. * * The post object was queried with a partial set of * fields, populate the entire object for the loop. */ $post = get_post( $post->ID ); } } // Set up the global post object for the loop. $this->setup_postdata( $post ); }Changelog
Introduced in 1.5.0. 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/class-wp-query.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.