WordPress at a glance
function is not described

is_client_error() WP 1.0

No Hooks.

Return

null. Nothing.

Usage

is_client_error ( $sc );
$sc (required)
-

Code of is_client_error() WP 5.7.2

<?php
function is_client_error ($sc) {
	return $sc >= 400 && $sc < 500;
}