spawn_cron( int $gmt_time = 0 ): bool

Compatibility

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

Parameters

$gmt_timeintoptional

Unix timestamp (UTC). Default 0 (current time is used).Default: 0

Return value

bool

True if spawned, false if no events spawned.

Performance profile

How much work a call to spawn_cron() 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_remote_post().

Scaling

Constant

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

Instructions

5–93

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 140.

Plugin surface

2 hooks

Third-party callbacks on 'cron_request', 'https_local_ssl_verify' run inside this call, and their cost is not bounded by anything here.

Called by

1

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

What it touches

• transienttransientget_transient()called directly
• hookthird-party callbacksapply_filters()called directly
• httpoutbound HTTP requestwp_remote_post()called directly
• cacheobject cachewp_cache_get()one call below spawn_cron()
• optionoption read or writeget_option()one call below spawn_cron()

Further down the call graph this can also reach serialize and query. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 12 distinct outcomes

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

Hooks and filters fired · 2

2 hooks fire while spawn_cron() runs, in this order:

1. 1
   apply_filters( cron_request )filterline 984 (+85 into the body)

   Filters the cron request arguments.

2. 2
   apply_filters( https_local_ssl_verify )filterline 993 (+94 into the body)

   Filters whether SSL should be verified for local HTTP API requests.

Uses · 11

• get_transient()Retrieves the value of a transient.
• wp_get_ready_cron_jobs()Retrieves cron jobs ready to be run.
• set_transient()Sets/updates the value of a transient.
• wp_redirect()Redirects to another page.
• add_query_arg()Retrieves a modified URL query string.
• wp_unslash()Removes slashes from a string or recursively removes slashes from strings within an array.
• wp_ob_end_flush_all()Flushes all output buffers for PHP 5.2.
• site_url()Retrieves the URL for the current site where WordPress application files (e.g. wp-blog-header.php or the wp-admin/ folder) are accessible.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• wp_remote_post()Performs an HTTP request using the POST method and returns its response.
• is_wp_error()Checks whether the given variable is a WordPress Error.

Used by · 1

• _wp_cron()Runs scheduled callbacks or spawns cron for all scheduled events.

Source code

View on Trac ↗View on GitHub ↗

899function spawn_cron( $gmt_time = 0 ) {900	if ( ! $gmt_time ) {901		$gmt_time = microtime( true );902	}903 904	if ( defined( 'DOING_CRON' ) || isset( $_GET['doing_wp_cron'] ) ) {905		return false;906	}907 908	/*909	 * Get the cron lock, which is a Unix timestamp of when the last cron was spawned910	 * and has not finished running.911	 *912	 * Multiple processes on multiple web servers can run this code concurrently,913	 * this lock attempts to make spawning as atomic as possible.914	 */915	$lock = (float) get_transient( 'doing_cron' );916 917	if ( $lock > $gmt_time + 10 * MINUTE_IN_SECONDS ) {918		$lock = 0;919	}920 921	// Don't run if another process is currently running it or more than once every 60 sec.922	if ( $lock + WP_CRON_LOCK_TIMEOUT > $gmt_time ) {923		return false;924	}925 926	// Confidence check.927	$crons = wp_get_ready_cron_jobs();928	if ( empty( $crons ) ) {929		return false;930	}931 932	$keys = array_keys( $crons );933	if ( isset( $keys[0] ) && $keys[0] > $gmt_time ) {934		return false;935	}936 937	if ( defined( 'ALTERNATE_WP_CRON' ) && ALTERNATE_WP_CRON ) {938		if ( 'GET' !== $_SERVER['REQUEST_METHOD'] || defined( 'DOING_AJAX' ) || defined( 'XMLRPC_REQUEST' ) ) {939			return false;940		}941 942		$doing_wp_cron = sprintf( '%.22F', $gmt_time );943		set_transient( 'doing_cron', $doing_wp_cron );944 945		ob_start();946		wp_redirect( add_query_arg( 'doing_wp_cron', $doing_wp_cron, wp_unslash( $_SERVER['REQUEST_URI'] ) ) );947		echo ' ';948 949		// Flush any buffers and send the headers.950		wp_ob_end_flush_all();951		flush();952 953		require_once ABSPATH . 'wp-cron.php';954		return true;955	}956 957	// Set the cron lock with the current unix timestamp, when the cron is being spawned.958	$doing_wp_cron = sprintf( '%.22F', $gmt_time );959	set_transient( 'doing_cron', $doing_wp_cron );960 961	$cron_url = add_query_arg( 'doing_wp_cron', $doing_wp_cron, site_url( 'wp-cron.php' ) );962 963	/**964	 * Filters the cron request arguments.965	 *966	 * @since 3.5.0967	 * @since 4.5.0 The `$doing_wp_cron` parameter was added.968	 *969	 * @param array $cron_request_array {970	 *     An array of cron request URL arguments.971	 *972	 *     @type string $url  The cron request URL.973	 *     @type string $key  The Unix timestamp (UTC) of the cron lock with microseconds.974	 *     @type array  $args {975	 *         An array of cron request arguments.976	 *977	 *         @type int  $timeout   The request timeout in seconds. Default .01 seconds.978	 *         @type bool $blocking  Whether to set blocking for the request. Default false.

Changelog

Introduced in 2.1.0. Unchanged from 6.7.7 through 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 7.1.0 tag, from src/wp-includes/cron.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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