func IPVar(value *net.IP, names []string, defaultValue, usage string) { flag.Var(NewIpOpt(value, defaultValue), names, usage) }
func DnsSearchListVar(values *[]string, names []string, usage string) { flag.Var(newListOptsRef(values, ValidateDnsSearch), names, usage) }
func HostListVar(values *[]string, names []string, usage string) { flag.Var(newListOptsRef(values, api.ValidateHost), names, usage) }
func IPListVar(values *[]string, names []string, usage string) { flag.Var(newListOptsRef(values, ValidateIPAddress), names, usage) }
func ListVar(values *[]string, names []string, usage string) { flag.Var(newListOptsRef(values, nil), names, usage) }