WordPress at a glance
function is not described

wc_cart_round_discount() WC 1.0

Round discount.

No Hooks.

Return

float. Nothing.

Usage

wc_cart_round_discount( $value, $precision );
$value(double) (required)
Amount to round.
$precision(int) (required)
DP to round.

Code of wc_cart_round_discount() WC 5.3.0

<?php
function wc_cart_round_discount( $value, $precision ) {
	return wc_round_discount( $value, $precision );
}