WordPress at a glance
function is not described

update_comment_cache() WP 2.3.0

Updates the comment cache of given comments.

Will add the comments in $comments to the cache. If comment ID already exists in the comment cache then it will not be updated. The comment is added to the cache using the comment group with the key using the ID of the comments.

No Hooks.

Return

null. Nothing.

Usage

update_comment_cache( $comments, $update_meta_cache );
$comments(WP_Comment[]) (required)
Array of comment objects
$update_meta_cache(true|false)
Whether to update commentmeta cache.
Default: true

Changelog

Since 2.3.0 Introduced.
Since 4.4.0 Introduced the $update_meta_cache parameter.

Code of update_comment_cache() WP 5.7.2

<?php
function update_comment_cache( $comments, $update_meta_cache = true ) {
	foreach ( (array) $comments as $comment ) {
		wp_cache_add( $comment->comment_ID, $comment, 'comment' );
	}

	if ( $update_meta_cache ) {
		// Avoid `wp_list_pluck()` in case `$comments` is passed by reference.
		$comment_ids = array();
		foreach ( $comments as $comment ) {
			$comment_ids[] = $comment->comment_ID;
		}
		update_meta_cache( 'comment', $comment_ids );
	}
}