ver := string(out[:4])
			tl, _ := strconv.Atoi(string(out[5:7]))
			unStrmDgramEnabled = ver > "7200" || (ver == "7200" && tl >= 2)
		}
	default:
		unStrmDgramEnabled = true
	}
}

func unixStrmDgramEnabled() bool {
	stackOnce.Do(probeStack)
	return unStrmDgramEnabled
}

// SupportsIPv4 reports whether the platform supports IPv4 networking
// functionality.
func SupportsIPv4() bool {
	stackOnce.Do(probeStack)