2007-06-18 ISC Internet Systems Consortium, Inc. lwres_getnameinfo 3 BIND9 2000 2001 2004 2005 2007 2014 2015 2016 2018 2019 Internet Systems Consortium, Inc. ("ISC") lwres_getnameinfo lightweight resolver socket address structure to hostname and service name #include <lwres/netdb.h> int lwres_getnameinfo const struct sockaddr *sa size_t salen char *host size_t hostlen char *serv size_t servlen int flags This function is equivalent to the getnameinfo3 function defined in RFC2133. lwres_getnameinfo() returns the hostname for the struct sockaddr sa which is salen bytes long. The hostname is of length hostlen and is returned via *host. The maximum length of the hostname is 1025 bytes: NI_MAXHOST. The name of the service associated with the port number in sa is returned in *serv. It is servlen bytes long. The maximum length of the service name is NI_MAXSERV - 32 bytes. The flags argument sets the following bits: NI_NOFQDN A fully qualified domain name is not required for local hosts. The local part of the fully qualified domain name is returned instead. NI_NUMERICHOST Return the address in numeric form, as if calling inet_ntop(), instead of a host name. NI_NAMEREQD A name is required. If the hostname cannot be found in the DNS and this flag is set, a non-zero error code is returned. If the hostname is not found and the flag is not set, the address is returned in numeric form. NI_NUMERICSERV The service name is returned as a digit string representing the port number. NI_DGRAM Specifies that the service being looked up is a datagram service, and causes getservbyport() to be called with a second argument of "udp" instead of its default of "tcp". This is required for the few ports (512-514) that have different services for UDP and TCP. lwres_getnameinfo() returns 0 on success or a non-zero error code if an error occurs. RFC2133 , getservbyport3 , lwres3 , lwres_getnameinfo3 , lwres_getnamebyaddr3 . lwres_net_ntop3 . RFC2133 fails to define what the nonzero return values of getnameinfo3 are.