WordPress at a glance
function is not described

wp_throttle_comment_flood() WP 2.1.0

Whether a comment should be blocked because of comment flood.

No Hooks.

Return

true/false. Whether comment should be blocked.

Usage

wp_throttle_comment_flood( $block, $time_lastcomment, $time_newcomment );
$block(true/false) (required)
Whether plugin has already blocked comment.
$time_lastcomment(int) (required)
Timestamp for last comment.
$time_newcomment(int) (required)
Timestamp for new comment.

Code of wp throttle comment flood: wp-includes/comment.php VER 5.0.3

<?php
function wp_throttle_comment_flood($block, $time_lastcomment, $time_newcomment) {
	if ( $block ) // a plugin has already blocked... we'll let that decision stand
		return $block;
	if ( ($time_newcomment - $time_lastcomment) < 15 )
		return true;
	return false;
}