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function is not described

_update_blog_date_on_post_publish() WP 3.3.0

Handler for updating the site's last updated date when a post is published or an already published post is changed.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

No Hooks.

Return

null. Nothing.

Usage

_update_blog_date_on_post_publish( $new_status, $old_status, $post );
$new_status(string) (required)
The new post status.
$old_status(string) (required)
The old post status.
$post(WP_Post) (required)
Post object.

Changelog

Since 3.3.0 Introduced.

Code of _update_blog_date_on_post_publish() WP 5.7.2

<?php
function _update_blog_date_on_post_publish( $new_status, $old_status, $post ) {
	$post_type_obj = get_post_type_object( $post->post_type );
	if ( ! $post_type_obj || ! $post_type_obj->public ) {
		return;
	}

	if ( 'publish' !== $new_status && 'publish' !== $old_status ) {
		return;
	}

	// Post was freshly published, published post was saved, or published post was unpublished.

	wpmu_update_blogs_date();
}