WordPress at a glance
function is not described

valid_unicode() WP 2.7.0

Helper function to determine if a Unicode value is valid.

No Hooks.

Return

true/false. True if the value was a valid Unicode number

Usage

valid_unicode( $i );
$i(int) (required)
Unicode value

Code of valid unicode: wp-includes/kses.php VER 5.0.3

<?php
function valid_unicode($i) {
	return ( $i == 0x9 || $i == 0xa || $i == 0xd ||
			($i >= 0x20 && $i <= 0xd7ff) ||
			($i >= 0xe000 && $i <= 0xfffd) ||
			($i >= 0x10000 && $i <= 0x10ffff) );
}