Code-Snippets-Functions/Execute a function on a child site/W3 Total Cache/purge-cache-on-stock-update-in-woocommerce.txt

add_action( 'woocommerce_product_set_stock', 'w3tc_flush_all_custom', 999 );
add_action( 'woocommerce_variation_set_stock', 'w3tc_flush_all_custom', 999 );

function w3tc_flush_all_custom() {
    w3tc_flush_all();
}